ESE's works engine tuner [Archive] - Page 26

TZ350

22nd January 2012, 07:50

Engines must be derived from non-competition motorcycles.

CHAPTER 24

24 ROAD RACING - MINIATURE

24-1 The Miniature Road Racing class or `Bucket Racing’ as it is also known, shall be deemed
to include solo motorcycles and sidecars.

24-2 Motorcycles Technical:

24-2-1 Solo motorcycles shall have two engine capacity classes:
F4 2 stroke 55-100cc
2 stroke 55-125cc air cooled
4 stroke 55-150cc
F5 2 stroke 0-50cc
4 stroke 0-100cc air cooled

24-2-2 Sidecars shall have one engine capacity class:
2 stroke 55-100cc
2 stroke 55-125cc air cooled
4 stroke 55-150cc

24-2-3 The maximum capacity for rebored engines shall be:
F4 2 stroke 55-100cc - 104cc
2 stroke 55-125cc air cooled - 130.5cc
4 stroke 55-150cc – 158.09cc
F5 2 stroke 0-50cc - 53cc
4 stroke 0-100cc - 104cc

24-2-4 Engines must be derived from non-competition motorcycles. Motocross, Road Racing,
Enduro and Go Kart motors and transmission parts are not permitted. There shall be no
restriction on the make, type or design of carburettor, ignition, exhaust, piston, cam, valve
springs or cooling system except for class eligibility. All engines must be normally
aspirated except F4 4 stroke engines of less than 100cc capacity, which may be turbo or
supercharged.
F4 2 stroke engines over 104cc are restricted to carburation equivalent to a single 24mm
carburettor, F5 4 stroke engines over 53cc are restricted to carburation equivalent to a
single 20mm carburettor.

24-2-5 Fuel: See 10-17-1
Alcohol based fuel or fuel additives are prohibited.

24-2-6 Construction of Solo Motorcycles:
Miniature road racers are to be constructed in accordance with, and comply with, Chapter
10.

Grabed this so that people who may not be familiar with Bucket Racing in NZ can see what the rules are.

My 125 2-Stroke is limited to Air Cooling and a 24mm Carb.

Developing a Bucket road racer, particularly a 2 stroke, it is not just about outright power, the tracks have to be considered and the most appropriate power spread developed. On tight go kart tracks drive out of the corner and reducing the number of gear changes required need to be looked at. Then there is handling and suspension set up, tyre pressures etc. It’s affordable and there is enough challenge here to keep a developer interested for a long time.

The easier it is to ride the easier it is to ride fast ......

Frits Overmars

22nd January 2012, 08:17

....Developing a Bucket road racer, particularly a 2 stroke, it is not just about outright power, the tracks have to be considered and the most appropriate power spread developed. On tight go kart tracks drive out of the corner and reducing the number of gear changes required need to be looked at. Then there is handling and suspension set up, tyre pressures etc. It's the same everywhere in racing (except dragracing): engine power may give you tenths of seconds; chassis setup will give you whole seconds.

dinamik2t

22nd January 2012, 08:30

Hey TZ, nice looking carb you got there!:sweatdrop I like blue!
As you observed everything looks very similar to the Lectrons. I used to have a 34 (http://s736.photobucket.com/albums/xx5/Vag1-2/Lectron34/) and now a 40 (http://s736.photobucket.com/albums/xx5/Vag1-2/lectron/) - both minus 2mm at the slide. Great carbs, easy to tune, crispy and steady at idle on the very first start-up. Hard to tune though, unless you purchase a couple of rods. (Thankfully I got an amazing deal on ebay once and got myself about 20 at zero cost)

Here's the dimensions to the 40 lectron:
255652

and here's some carbs I have in EndMod data, if anybody wants them:
http://users.uoa.gr/~sph0800108/modenas_dinamik_forum/EngMod2T/Carbs.rar
There's 2 PWKs 38, the two lectrons and one Dellorto 30.

Good idea about pointing out the regulations.
Since you're kind of near to Malaysia and Thailand, why don't you get one of the mopped engines from there??
They're aircooled and below the 125cc limit. Reed valved and quite modern for low cost production engines, in every aspect.
We have the same mopped bikes here and we tune those engines a lot. It's actually the engine I tune myself.

I have tons of photos here if you're interested: http://s736.photobucket.com/albums/xx5/Vag1-2/

TZ350

22nd January 2012, 09:54

Thanks for the EngMod2T carb dimensions and photos, very usefull.

Malaysia and Thailand are still not that easy to get too 13-14 hours flying time. I once had a good look around Bangkok for suitable engines, I got a few carburettors but there was not much engine stuff to be found and I found it hard to organise shipping anyway. Thomas was back home in Veitnam recently and he found the same thing. You would think there would be wrecker yards full of them but something happens to the old bikes, they just seem to dissapear.

TerraRoot

22nd January 2012, 11:44

is there not some kind of thai/malay version of ebay/trademe?

TZ350

22nd January 2012, 12:00

255657

I just had a look at a world map, London is on the opposite side of the world to us and Thailand and Malaysia are nearly half way there, so they are half way around the world from us, so not exactly next door, in fact your about as close as we are.

255658
1920's map of the British Empire

There was a time when the sun never set on the British empire.

255660

Countries that still have the Queen of England as Head of State.

255796

Now we are one of the very few remaining self governing former colonies that still has the Queen as head of state,

255794 Lady Gaga is presented to the Queen.

and as we are those Islands in the bottom right hand corner of the map we are about as far away from Britain or anywhere else as you can get, except for maybe the South Pole and Happy Feet the penguin.

255795

husaberg

22nd January 2012, 12:22

is there not some kind of thai/malay version of ebay/trademe?

Yes there is the problem we have is a lot of traders don't want to go to the hassle of shipping overseas.
ESP with heavy things like engines.
There is a available in the Asian countries called the Nova Dash 125 it is water cooled Crankcase Reed engine 2 stroke 6 speed but according to Matt at Tyga it is unsexy in the internals it also has a 52mm stroke and no power valve, I do wonder if another cylinder could be added, But it did look promising though. The engine that is. The Nova Dash has now became a boring old Four stroke.
255659
http://imageshack.us/photo/my-images/294/82410196.jpg/
[/URL]http://images.jadracing.multiply.com/image/1/photos/68/600x600/44/DSC02211.JPG?et=tyO4vKC3%2By8O3Rm751f7VQ&nmid=320905780 (http://www.kiwibiker.co.nz/images.jadracing.multiply.com/image/1/photos/68/600x600/44/DSC02211.JPG?et=tyO4vKC3%2By8O3Rm751f7VQ&nmid=320905780)
The link below is the dash engine strip

[URL]http://www.youtube.com/watch?v=JrjBVx3MAx0&feature=related

The stripped down racing Model Pic 4 is the one i would be willing to import

http://translate.google.co.nz/translate?hl=en&sl=id&u=http://dwinugros.wordpress.com/2011/04/25/honda-new-nova-dash-125-honda-nova-series-tamat/& (http://translate.google.co.nz/translate?hl=en&sl=id&u=http://dwinugros.wordpress.com/2011/04/25/honda-new-nova-dash-125-honda-nova-series-tamat/&ei=kFYbT7_fHsqjiAerzvnjCw&sa=X&oi=translate&ct=result&resnum=1&ved=0CCQQ7gEwAA&prev=/search%3Fq%3Dnova%2Bdash%2B125%2B2%2Bstroke%26hl%3 Den%26sa%3DX%26biw%3D1280%26bih%3D827%26prmd%3Dimv nsfd)
http://tra (http://translate.google.co.nz/translate?hl=en&sl=id&u=http://dwinugros.wordpress.com/2011/04/18/honda-nova-dash-125-honda-nova-series-bagian-3/&ei=oFJoTuq2GtGfiAfvo8DtDg&sa=X&oi=translate&ct=result&resnum=1&ved=0CCQQ7gEwAA&prev=/search%3Fq%3DHonda%2BNew%2BNova%2BDash%2B125%2B(Ho nda%2BNova%2BSeries%2B–%2BTamat).%26hl%3Den%26biw% 3D1280%26bih%3D799%26prmd%3Divns)

Pic 6 is the racing Model you will finish first with this one

Here is a link to a write up on them
(http://translate.google.co.nz/translate?hl=en&sl=id&u=http://dwinugros.wordpress.com/2011/04/25/honda-new-nova-dash-125-honda-nova-series-tamat/&ei=kFYbT7_fHsqjiAerzvnjCw&sa=X&oi=translate&ct=result&resnum=1&ved=0CCQQ7gEwAA&prev=/search%3Fq%3Dnova%2Bdash%2B125%2B2%2Bstroke%26hl%3 Den%26sa%3DX%26biw%3D1280%26bih%3D827%26prmd%3Dimv nsfd)nslate.google.co.nz/translate?hl=en&sl=id&u=http://dwinugros.wordpress.com/2011/04/18/honda-nova-dash-125-honda-nova-series-bagian-3/&ei=oFJoTuq2GtGfiAfvo8DtDg&sa=X&oi=translate&ct=result&resnum=1&ved=0CCQQ7gEwAA&prev=/search%3Fq%3DHonda%2BNew%2BNova%2BDash%2B125%2B(Ho nda%2BNova%2BSeries%2B–%2BTamat).%26hl%3Den%26biw% 3D1280%26bih%3D799%26prmd%3Divns (http://translate.google.co.nz/translate?hl=en&sl=id&u=http://dwinugros.wordpress.com/2011/04/18/honda-nova-dash-125-honda-nova-series-bagian-3/&ei=oFJoTuq2GtGfiAfvo8DtDg&sa=X&oi=translate&ct=result&resnum=1&ved=0CCQQ7gEwAA&prev=/search%3Fq%3DHonda%2BNew%2BNova%2BDash%2B125%2B(Ho nda%2BNova%2BSeries%2B–%2BTamat).%26hl%3Den%26biw% 3D1280%26bih%3D799%26prmd%3Divns)

(http://translate.google.co.nz/translate?hl=en&sl=id&u=http://dwinugros.wordpress.com/2011/04/25/honda-new-nova-dash-125-honda-nova-series-tamat/&ei=kFYbT7_fHsqjiAerzvnjCw&sa=X&oi=translate&ct=result&resnum=1&ved=0CCQQ7gEwAA&prev=/search%3Fq%3Dnova%2Bdash%2B125%2B2%2Bstroke%26hl%3 Den%26sa%3DX%26biw%3D1280%26bih%3D827%26prmd%3Dimv nsfd)

(http://translate.google.co.nz/translate?hl=en&sl=id&u=http://dwinugros.wordpress.com/2011/04/25/honda-new-nova-dash-125-honda-nova-series-tamat/&ei=kFYbT7_fHsqjiAerzvnjCw&sa=X&oi=translate&ct=result&resnum=1&ved=0CCQQ7gEwAA&prev=/search%3Fq%3Dnova%2Bdash%2B125%2B2%2Bstroke%26hl%3 Den%26sa%3DX%26biw%3D1280%26bih%3D827%26prmd%3Dimv nsfd)

Grumph

22nd January 2012, 12:38

The bucket racer in the pic looks promising - looks like you could drop RS125 'glass straight on.

Whoever perforated the front disc went a tad far though IMO.....

2T Institute

22nd January 2012, 18:48

Buckets is about using as little as brake as possible.

husaberg

22nd January 2012, 19:10

Buckets is about using as little as brake as possible.

That asian bike is obviously trying to keep the tire friction/drag down as well
255691255692255695Much like these fellows

One very much like this does
the standing Quarter in 11.3 seconds

<tbody>
Nova Dash sprinter from here.http://nsr-world.com/weird/

The custom ported cylinder is bored out to a little over 160cc and fitted with a Wiseco single ring piston. Fuelling is by an open 38mm (yes 38mm!!) RS125 Keihin, and the expansion chamber is hand made stainless steel based heavily on an A-kit RS125 system. Silencing is sort of taken care of by a kevlar stinger!
These little drag bikes are all about screaming motors and light weight, just look at the holes drilled throughout the frame! The usual pressed steel swing-arm has been replaced with a custom alloy unit too.
The stock Dash peaks at 7000rpm, this little screamer revs on to 12,000rpm utilising an adjustable ignition unit. Although these bikes are never dyno'd, their performance figures are outstanding... this particular bike covers a standing quarter mile in just 11.3 seconds! Not bad for a "girly shopping" bike!!!

</tbody>

dinamik2t

22nd January 2012, 21:48

Yes, (honda) dash is the watercooled one! I thiink they mostly fit in CR/NSR cylinders there..

There is also Modenas Dinamik 120 (which is a Kawasaki). That's aircooled and 54X51.8 . 14mm wrist pin, not much "125s" pistons to fit..
Parts diagram: http://users.uoa.gr/~sph0800108/modenas_dinamik_forum/Dinamik_-_Parts_Diagrams_Pass-OneHalfR.pdf

And Yamaha 125Z/ZR, aircooled and 53.8X54.7 . 16mm wrist-pin, large variety of pistons to fit.
Parts diagram: http://users.uoa.gr/~sph0800108/modenas_dinamik_forum/125z%20part%20catalog%202004.pdf

None of the two has powervalves though.

koba

23rd January 2012, 10:35

Buckets is about using as little as brake as possible.

Not on so much on kart tracks.

richban

23rd January 2012, 11:08

Not on so much on kart tracks.

I reckon the same rules apply on Kart, and big tracks. If you aren't on the breaks best be getting on the gas.

breezy

23rd January 2012, 11:24

255754255755255756255757255758 bsa bantam grafting on rgv barrel. bucket style. still a fair way to go!!

TZ350

23rd January 2012, 11:34

BSA Bantam, RGV, very interesting combo .... what are you building, tell us more ......

Grumph

23rd January 2012, 12:04

Is that legal for Formula bantam ? Out here you'd build it up aircooled for Classic racing - and run it on Methanol.....

You're still limited by the 'box ratios though aren't you ?

husaberg

23rd January 2012, 18:16

BSA Bantam, RGV, very interesting combo .... what are you building, tell us more ......

BSA Bantam with a RGV top end is an EGGcellent idea :yes:

Yes, (honda) dash is the watercooled one! I thiink they mostly fit in CR/NSR cylinders there..

There is also Modenas Dinamik 120 (which is a Kawasaki). That's aircooled and 54X51.8 . 14mm wrist pin, not much "125s" pistons to fit..
Parts diagram: http://users.uoa.gr/~sph0800108/modenas_dinamik_forum/Dinamik_-_Parts_Diagrams_Pass-OneHalfR.pdf

And Yamaha 125Z/ZR, aircooled and 53.8X54.7 . 16mm wrist-pin, large variety of pistons to fit.
Parts diagram: http://users.uoa.gr/~sph0800108/modenas_dinamik_forum/125z part catalog 2004.pdf

None of the two has powervalves though.

A couple more for the pot.
It looks like these owe a little to the MB/H series

Although one of them at least looks crankcase reed.

 Honda Nova RS

http://translate.google.co.nz/translate?hl=en&sl=id&u=http://dwinugros.wordpress.com/2011/04/18/honda-nova-dash-125-honda-nova-series-bagian-3/&ei=oFJoTuq2GtGfiAfvo8DtDg&sa=X&oi=translate&ct=result&resnum=1&ved=0CCQQ7gEwAA&prev=/search%3Fq%3DHonda%2BNew%2BNova%2BDash%2B125%2B(Ho nda%2BNova%2BSeries%2B–%2BTamat).%26hl%3Den%26biw% 3D1280%26bih%3D799%26prmd%3Divns (http://translate.google.co.nz/translate?hl=en&sl=id&u=http://dwinugros.wordpress.com/2011/04/18/honda-nova-dash-125-honda-nova-series-bagian-3/&ei=oFJoTuq2GtGfiAfvo8DtDg&sa=X&oi=translate&ct=result&resnum=1&ved=0CCQQ7gEwAA&prev=/search%3Fq%3DHonda%2BNew%2BNova%2BDash%2B125%2B(Ho nda%2BNova%2BSeries%2B–%2BTamat).%26hl%3Den%26biw% 3D1280%26bih%3D799%26prmd%3Divns)

Honda Nova Tena RS 110
http://translate.google.co.nz/translate?hl=en&sl=id&u=http://dwinugros.wordpress.com/2011/04/18/honda-nova-dash-125-honda-nova-series-bagian-3/&ei=oFJoTuq2GtGfiAfvo8DtDg&sa=X&oi=translate&ct=result&resnum=1&ved=0CCQQ7gEwAA&prev=/search%3Fq%3DHonda%2BNew%2BNova%2BDash%2B125%2B(Ho nda%2BNova%2BSeries%2B–%2BTamat).%26hl%3Den%26biw% 3D1280%26bih%3D799%26prmd%3Divns

husaberg

23rd January 2012, 22:51

Question for Frits

What happens at Aprillia after 95-96.
Aprilia has won the 125 and 250 gp champs
What does the team concentrate on?
It it on making them more drivable, or testing new combinations?
Lots of Pipe testing?
No doubt all of the above.
what does the development team do in an average day?

breezy

23rd January 2012, 22:53

255754255755255756255757255758 bsa bantam grafting on rgv barrel. bucket style. still a fair way to go!!

well, thought i do some reverse engineering by attaching this rgv barrell id got lying around, to some bantam cases.i noticed, from other bikes in the bantam racing world,that they were restricted by the crankcase where the barrel sat on without some major alloy welding .so i decided to chopit off and build up a larger flatter surface to house the barrel( all with bolts at present, to later have welded on). this barrel its not legal with the current rules, but if it works out i can try to produce a legal barrel with the same spec.maybe. im hoping to get a barrell with the reed inlet already on as if i stick with the rgv im gonna have to some how find a away to get the fuel in, but for know its usefull as a mock up . ive just ordered up some alloy plate to use as a spacer under the barrel,as my last attempts to melt/sandacast almost removed all the skin from my throat whilst checking what was going on in my home made furnace... (yeah well funny)eye brows who needs em.so there you have it. DO or DIE......will post some more as i progress if only for entertainment factor, should my posts never appear again itll because my home made still has gone bang!!! ha ha

breezy

23rd January 2012, 23:17

picture of the bike im hoping to race this year. 175c bantam rules..255816 this is what it looked like untill i decided to paint it british racing green(cant find picture in files at the moment). rs aprilia 125 fairing, tank, rear seat, rd 200 front forks and wheel. engine spec 3 speed close ratio box,steelplate clutch,34mm mikuni, standard head on at present(10;1), up and over home made exhaust , exhaust port 30mm from top of cast barrel, transfers 47mm from top of barrel,cant remember inlet duration.i did once post on u tube a while back , bsa bantam race bike,but not sure if its still there. ive not raced this bike yet,but ive got to get going this year as ive been to long messing around.

Frits Overmars

24th January 2012, 00:30

Question for Frits. What happens at Aprillia after 95-96. Aprilia has won the 125 and 250 gp champs. What does the team concentrate on? It it on making them more drivable, or testing new combinations? Lots of Pipe testing? No doubt all of the above. what does the development team do in an average day?Can you remember what you were doing 16 years ago, Husa? Not me, not without diving into a cubic meter of paper work, which I don't fancy right now (or ever). So it's 'all of the above'.
What I do remember, is this. Jan Thiel joined Aprilia in early 1995. He started working on the 125 cc Rotax engine, while the 250-team was working on Biaggi's V-twin. The Biaggi-team used very special cylinders (in reality designed by the Austrian AVL company) and Jan wasn't even allowed a look into them - until the 250-team found out that Jan's somewhat modified run-of-the-mill Rotax production cylinders not only produced more power, but also had a wider power band.

On an average test day the average development team waits, talks and drinks coffee, and that's the truth. In the days before a test day a lot of schedules are prepared and a lot of material is collected and loaded into the team truck(s). On the test day you drive to Mugello (Aprilia's usual test track) or to Jerez in Spain where it's always sunny, even when Mugello is covered in snow (if it's Jerez, obviously you start driving a couple of days before the test day).
On the test day half of the test schedule cannot be carried out because some two dollar part was left behind, and the other half of the schedule is drowned by rain on the track (in Jerez...). Hence the waiting, talking (cursing, more like) and coffee drinking.

On a more cheerful note, the test rider was Marcellino Lucchi. His day job was driving the garbage truck in his home village, but whenever Aprilia needed him he made sure he was available to ride Biaggi's works bike. When Biaggi went on to ride the works Honda NSR500, the Aprilia test team had a good day in Jerez each time Lucchi was faster on the 250 than Biaggi was on the 500 (Jerez is that kind of track, and Lucchi could beat anybody there blindfolded. And superstar Biaggi had always been less-than-popular with the Aprilia mechanics).
Once a year Lucchi got a wild card and was allowed to take part in a real Grand Prix, at his home track Mugello. He usually grabbed third place, always the oldest man on the rostrum (he was well in his fourties then). Great character!

dinamik2t

24th January 2012, 06:52

wobbly

24th January 2012, 07:05

My reaction would be that the RSA "model " that took years to develop and had a mile of devil in the details, will work best in any bore - as long as the stroke ratio is maintained.
Thus both the radial and axials could be copied as all you are doing is scaling equally in both directions.
I know Frits has done just that ( and so have I ) using the scale model feature in SolidWorks - easy.

The radial angles set the directions to minimise short circuiting, and the axials maximise the scavenging purity - both together form the loop shape and duration.
Anything other than a square bore/stroke and you have instantly compromised the angle area capability, and all the R & D done by Aprilia is null and void.

husaberg

24th January 2012, 17:50

Can you remember what you were doing 16 years ago, Husa? Not me, not without diving into a cubic meter of paper work, which I don't fancy right now (or ever). So it's 'all of the above'.
What I do remember, is this. Jan Thiel joined Aprilia in early 1995. He started working on the 125 cc Rotax engine, while the 250-team was working on Biaggi's V-twin. The Biaggi-team used very special cylinders (in reality designed by the Austrian AVL company) and Jan wasn't even allowed a look into them - until the 250-team found out that Jan's somewhat modified run-of-the-mill Rotax production cylinders not only produced more power, but also had a wider power band.

On an average test day the average development team waits, talks and drinks coffee, and that's the truth. In the days before a test day a lot of schedules are prepared and a lot of material is collected and loaded into the team truck(s). On the test day you drive to Mugello (Aprilia's usual test track) or to Jerez in Spain where it's always sunny, even when Mugello is covered in snow (if it's Jerez, obviously you start driving a couple of days before the test day).
On the test day half of the test schedule cannot be carried out because some two dollar part was left behind, and the other half of the schedule is drowned by rain on the track (in Jerez...). Hence the waiting, talking (cursing, more like) and coffee drinking.

On a more cheerful note, the test rider was Marcellino Lucchi. His day job was driving the garbage truck in his home village, but whenever Aprilia needed him he made sure he was available to ride Biaggi's works bike. When Biaggi went on to ride the works Honda NSR500, the Aprilia test team had a good day in Jerez each time Lucchi was faster on the 250 than Biaggi was on the 500 (Jerez is that kind of track, and Lucchi could beat anybody there blindfolded. And superstar Biaggi had always been less-than-popular with the Aprilia mechanics).
Once a year Lucchi got a wild card and was allowed to take part in a real Grand Prix, at his home track Mugello. He usually grabbed third place, always the oldest man on the rostrum (he was well in his fourties then). Great character!

Thanks Frits I'd like to Think I am not that mean to ask for all the details,But just an overview was what i was after. So thanks.
I had a look at the stuff on Lucchi (I had heard of him but only periphery)
Wow long career first race to last race. 22 years in GP's.

Marcellino Lucchi (born on March 13, 1957 in Cesna was an Italian Grand Prix. His best year was in 1998 (http://en.wikipedia.org/wiki/1998_Grand_Prix_motorcycle_racing_season) when he won the Italian Grand Prix (http://en.wikipedia.org/wiki/Italian_motorcycle_Grand_Prix) and finished 15th in the 250cc world championship.[1] (http://en.wikipedia.org/wiki/Marcellino_Lucchi#cite_note-0#cite_note-0)
Weight: 66 kg

<tbody>
Motorcycle racing career statistics

Grand Prix motorcycle racing (http://en.wikipedia.org/wiki/Grand_Prix_motorcycle_racing)

Active years
1982 (http://en.wikipedia.org/wiki/1982_Grand_Prix_motorcycle_racing_season) - 1991 (http://en.wikipedia.org/wiki/1991_Grand_Prix_motorcycle_racing_season), 1993 (http://en.wikipedia.org/wiki/1993_Grand_Prix_motorcycle_racing_season) - 2001 (http://en.wikipedia.org/wiki/2001_Grand_Prix_motorcycle_racing_season), 2004 (http://en.wikipedia.org/wiki/2004_Grand_Prix_motorcycle_racing_season)

First race
1982 (http://en.wikipedia.org/wiki/1982_Grand_Prix_motorcycle_racing_season) 250cc Nations Grand Prix (http://en.wikipedia.org/wiki/Italian_motorcycle_Grand_Prix)

Last race
2004 (http://en.wikipedia.org/wiki/2004_Grand_Prix_motorcycle_racing_season) 250cc Malaysian Grand Prix (http://en.wikipedia.org/wiki/Malaysian_motorcycle_Grand_Prix)

First win
1998 (http://en.wikipedia.org/wiki/1998_Grand_Prix_motorcycle_racing_season) 250cc Italian Grand Prix (http://en.wikipedia.org/wiki/Italian_motorcycle_Grand_Prix)

Last win
1998 (http://en.wikipedia.org/wiki/1998_Grand_Prix_motorcycle_racing_season) 250cc Italian Grand Prix (http://en.wikipedia.org/wiki/Italian_motorcycle_Grand_Prix)

<tbody>
Starts
Wins
Podiums
Poles (http://en.wikipedia.org/wiki/Pole_position)
F. laps (http://en.wikipedia.org/wiki/Fastest_lap)
Points

78
1
5
3
1
278

</tbody>

</tbody>

Unfortunately i can remember what i did around that time with tedious detail as it mainly involved a lot of PD's on TRX300's @$6.66/Hour NZD
The main detail i was after was the structure and how many dyno test were done compared to track tests.
I recall something about Bud Askland doing something like 3000 dyno runs a year for Roberts so i assume this was on top of Yamaha's testing program as well.

Honda is credited with only 200 employees at this time in HRC out of 10000 Honda motorcycle employees.

I had seen there was something along the lines of the Aprilia GP race programs employees totaling 62, out of 450 of the total employees of the Marque.
Incredibly it is also said that they were an additional 60 odd were engaged in R&D of other sorts as well.
So that is an Huge investment in anyone terms and one that paid dividends as well.

I say investment as that is how i see it as what it was.
As assuming they (Aprilia) spent 6 Million USD of there own money in 95 on racing. That is incredibly cheap, compared to advertising on TV and compared to the print coverage Aprilia's success brought them.

Max Biaggi
I have read a lot of the stuff Max wrote and yeah er....interesting guy. Admittedly a great rider but not exactly humble. It must have been a challenge finding a helmet large enough to fit him.:innocent:

koba

24th January 2012, 21:28

I've been trying to think of an intelligent question to ask of our learned contributors for a while.

There have been heaps of things that have sprung to mind but I've been able to find reasonable answers myself by looking around and reading widely, asking such questions here seems a waste of a good opportunity.

So my odd-ball questions:

What is the up with the radial exhaust port angle?

I'm not sure if I have the correct term so I have attached a Picture to illustrate.

Some exhaust ports exit straight (pic on left) but I notice others, including the RS125 barrel I have sitting here, have a shape more like in the right picture.

I can guess at why this might be done but is there any general wisdom of perceived benefits/drawbacks?

I did notice one small reference to it in the large pile of books I've been working through, that was in Cesare Bossaglia's book 'Two Stroke High Performance Engine Design and Tuning' (Quite an old book but still interesting and informative, a greater scope than most) from my terrible memory he said it has been used to update old barrels to higher performance without a major redesign.

Frits Overmars

24th January 2012, 22:36

Frits, may I ask a question too.. It's about port layout/axial-radial angles VS bore-stroke. For high performance engines at least. Say this is RSA's port layout, which is a 54 bore by 54.5 stroke. 255827
Also axial angles are 28-7-52.5 for TFRs A-B-C.
I believe I am thinking this one correct: Radials should form a shape like in the above pic, where Bs' flow collide in the middle of the lower bore half and -pretty much- As' flow surround them, also colliding in the middle of the lower half.
So, if we had a 60mm bore, it's the general shape that should be similar and not the numbers as stated in the pic. Ie the 60mm shouldn't have the Bs at -12/-16, but at -13.3/-17.8. In other words, if someone had to create a similar pattern, he should use the normalized (to the bore) numbers. Yes?
Now, about the axial angles and the stroke.
The 28* (or 7 or 52.5) direct the flow at, say, height h1 in the cylinder. And it creates the perfect scavenge model.
If we had a 50mm stroke and used 28* wouldn't height h1' be different than h1? Then the scavenge model would be less perfect, correct?
I am not sure if this is the correct way to think, it' s static analysis after all. Perhaps the smaller amount of time the 50 stroke has to reach h1' compensates the difference. And so, radial angle desing might become more universal.Your picture did not show on my computer, so I will have to guess what you mean by 'the 60mm shouldn't have the Bs at -12/-16, but at -13.3/-17.8'. But I think I've got a pretty good idea.
Most two-stroke people define radial scavenging directions by quoting the distances where the ports would intersect the center line (the leading distance and trailing distance in the drawing below left). Gordon Blair used that notation in his publications, and 95% of us followed suit.
But there is a better, more universally applicable way.
I will explain with an example, not of scavenging directions, but of port timing: I might say that a transfer port height of 13 mm is perfect for a racing engine. That may be true for a 125 cc engine, but it would be nonsense for a 50 cc.
But if I say that a transfer port timing of 130° is perfect for a racing engine, then that is valid for any engine, regardless of its cubic capacity. Absolute distance values (millimeters, inches etc.) are not suited for universal guidelines. Degrees are, as are percentages of bore or stroke. rpm values are not; mean piston velocities are.

I express transfer duct directions in degrees. Each duct has a leading flank and a trailing flank. Each flank intersects the bore at a point which I can define with a positional angle. And each flank hits the fore-aft center line of the bore with an included angle which I call the directional angle. The drawing below left may clarify what I mean. And the drawing on the right is an example of an existing cylinder (it may be small, 6.5 cc, but it has been unbeatable for over 10 years).

Now you can express the radial characteristics of the transfer ports with positional and directional angles, regardless of bore and stroke.
And you can express the ports' axial characteristics with axial angles, but that only holds for engines with identical bore/stroke-ratios, as Wobbly explained.
Your approach of using a height h1 in the cylinder where the transfer port's roof would hit the opposite cylinder wall, is very good, but you need to express h1 as a percentage of the stroke. Then you will have a truly universal value. Then you will also see that short-stroke engines require smaller axial angles.

dinamik2t

24th January 2012, 22:42

If you're refering generally to Ex ports - meaning bridged too, like RS125 - then one thing it helps with, is AREA.
A port like RS, which extends (by the wall) towards the middle of the bore, would have less effective area if it was straight or like in the left pic. The longer it goes towards the center, the larger the side wall angle (EngMod uses this term) should be.
I believe it's the same with the Auxiliary Ex ports too..

By the way, there are a couple of CFD sims of the loop scavenge in youtube: (hope they haven't been posted again soon)

http://www.youtube.com/watch?v=w8sidsux9D0
http://www.youtube.com/watch?v=3F_0PvbKo44
http://www.youtube.com/watch?v=M53nersJJ3o

-------------

I've also read Frits answer now.

Firstly, this was the pic - hope it's viewable now. I turned it to .jpeg

255963

Yes, you guessed very correctly. I first show this type of reference to radial angles in EngMod, to be honest, and then read it in Blair's book, which must be the original source for EngMod too.
Positional angles must be quite more easy to determine! In directional system, one must specify both the angle and the distance from the center.
I was curious about this for a long time, seeing your blue photos: have you created your own simulator/data program? :D I think that's great!
An amateur craftsman would start by using his bear hands and a few sandpapers. Then, as his experience and skill grows, he will be using the existant tools. At the time he starts making his own to suite his needs, he is no-word-to-describe-it-you-get-what-I-mean :P.

Continuing:

Your approach of using a height h1 in the cylinder where the transfer port's roof would hit the opposite cylinder wall, is very good, but you need to express h1 as a percentage of the stroke.

I actually thought of h1 as the point where port roof would hit the center, because it's there the streams meet. Would that be wrong?
edit: I realise on second thought, that it would be far far more diffucult to measure or refer to, than your way..

Frits Overmars

25th January 2012, 02:13

I was curious about this for a long time, seeing your blue photos: have you created your own simulator/data program? I think that's great!
An amateur craftsman would start by using his bear hands and a few sandpapers. Then, as his experience and skill grows, he will be using the existant tools. At the time he starts making his own to suite his needs, he is no-word-to-describe-it-you-get-what-I-meanBear hands? Not me; I started quite sophisticated, with a spanner # 10, a screwdriver and a hammer. After I while I felt the need for more dedicated tools which over the years led to writing a number of programs, including my own sim. And no, you need not ask; it is not for sale. I wrote it for my personal use only, so it is far from user-friendly and selling it would cause an avalanche of questions from users.

Frits Overmars

25th January 2012, 04:20

As we were on the subject of scavenging angles, now would be a good time to write something about the radial angles of the A-transfers.
Surely a duct with a radial angle of over 20° offers a smaller cross-section to the flow than a duct that enters the cylinder perpendicularly?
Yes it does. But there are two good reasons to angle it upward anyway.

First, perpendicular mixture streams coming from the A-ports would collide and slow one another right down. The upward angles provide for less velocity losses and less
pressure losses, so despite their smaller cross-section, upward ports may flow as much, if not more, than perpendicular ports.
(Now you may well ask why the B-ports do not get the same treatment; that is because the central scavenging column, resulting from all incoming scavenging streams together, must not have too much radial velocity, or the loop scavenging will result in a loop-loss into the exhaust).

Second, there is a thing called scavenging balance (I invented the word for my personal use, so this may well be the first time you ever saw it).
If you looked closely at the scavenging picture of the MB-cylinder I posted earlier today, you may have noticed that the 'radial scavenging directional resultant'
had a value of 101,045°.
90° would have meant 'straight up'; more than 90° indicates that the central scavenging column is leaning towards the exhaust side of the cylinder.
But we don't want that; it is bad for the scavenging of the rear part of the cylinder, and it is risky because it may provoke scavenging losses straight into the exhaust.

But how can we prevent a scavenging column from toppling over to the exhaust side like the leaning tower of Pisa? Not by pushing against its basis, but by pushing higher up. Hence the radial angle of the A-ports. The pictures will tell the story. (If only the Pisa architect had known a bit more about two-stroke tuning....)

gamma500

25th January 2012, 06:28

nice radial angles! :Punk:

dinamik2t

25th January 2012, 08:12

And no, you need not ask; it is not for sale. I wrote it for my personal use only, so it is far from user-friendly and selling it would cause an avalanche of questions from users.

Sorry, I thought you might get that idea or that other people might ask for it, after confirmation. But I trully didn't have such an intention when I asked you. Just for the reason I said earlier and of respect. I am quite happy with EngMod at the moment.
After all, these sort of tools is what makes each 'craftsman' unique, whether they are material objects or pairs of 0-1..
That's all about that. :)

:D and :clap: for the Pisa explanation of A ports! Now I wonder what the axial scavenging directional resultant represents though.

Frits Overmars

25th January 2012, 09:02

:D and :clap: for the Pisa explanation of A ports! Now I wonder what the axial scavenging directional resultant represents though.Your question is a perfect example of what I meant:
...I felt the need for more dedicated tools which over the years led to writing a number of programs, including my own sim....
I wrote it for my personal use only, so it is far from user-friendly and selling it would cause an avalanche of questions from users.Please don't feel embarrased. Here's a short explanation: the sine of this 'axial scavenging directional resultant' is an indication of the scavenging column's axial velocity. If the column moves too fast in relation to the mean piston velocity, there will be severe scavenging losses; if it doesn't move fast enough, the cylinder will not be completely scavenged.

dinamik2t

25th January 2012, 09:54

Aha!
I guess my time for questioning you is up, but this might not fall into the-art-of-tuning subject:
Derived from those scavenge measures. Can those streams be described as they are in reality -from the physics point of view- or there is some kind of model, inducing a certain amount of inaccuracy?
I have no idea from this part of physics, but I guess there must be huge 3D equations to describe those movements..

wobbly

25th January 2012, 11:07

The bulge, just outside the bore in the T port exhaust of an RS125/250 Honda type cylinder, hugely increases the flow rate during blowdown.
This increase in effective flow is dramatic enough, when compared to a straight sided exit, that it must be taken account of when modelling the port in EngMod2T.

F5 Dave

25th January 2012, 11:33

above answer is obviously refering to Kobas post.

I was going to say he didn't draw in the bridge in the picture which changes things somewhat.

Farmaken

25th January 2012, 11:46

Would the bulge have a similar effect on a single Ex port ??

F5 Dave

25th January 2012, 11:57

its not trying to avoid any obstruction.

TZ350

25th January 2012, 12:37

Page 240 bits and bobs, every other 10th page have collections too.

When using a simple powerjet nozzle the tip position matters in that no flow will occur until the slide is well past the exit hole, and there is sufficient airflow
to drag fuel up the feed tube above the bowl level.
With the aftermarket add ons and the ones as used by Lectron you can shorten the dump tube so that the flow will only occur at high slide openings,as well as high air flow.
These also have a built in "lag "control in that it takes time for the fuel to rise up the tube and dump out the exit into the air stream.
With a solenoid controlled setup all this is pretty much irrelevant as the flow can only occur when the solenoid is not powered up, and this
is TPS as well as rpm dependant inside the ECU program..
The carbs as used on the MX bikes has the dump tube very low in the bore as they added and subtracted fuel at low slide positions in those bikes.
For a race engine I bend the tube up to around 1/2 bore, as this is where the exit is on the Kehin SPJ carb for RS125/RS250 Honda.
And the general setting is the solenoid is powered up ie no flow below 4000 and 60% TPS and is powered up again at around 12400 to lean off the mixture and increase revon.
This causes a problem with Ignitions that are used with only a capacitor, as at startup the solenoid is powered up, dragging all the voltage out of the ECU, so I convert the ECU output
to a 3 step truth table, and have the setting such that below 1500rpm the solenoid isnt powered.

If Wiseco is your thing ....

New Zealand supplier in Auckland of Wiseco rings, sleeves and piston kits.

http://www.sportspro.co.nz/products/1150-engine/1036-wiseco_rings.aspx

A priceless tip. Never perform a modification you haven't done before on a part you still intend to use.

"If it ain't electric it can't be good" hmm? Sure, you can do all kind of tricks with drills, grinders, milling cutters etc. But there is nothing wrong with a file.

Two golden rules when modifying cylinders, pistons, etc:

One: stop before you reach the inscribed lines.

Two: wherever possible, do the finishing touches with a hand file.

It will save you a lot of errors. And if you are looking for a more 'technical' reason: grinding and milling will in general remove material perpendicular to the direction of flow; you risk producing a surface with a lot of pot holes. Filing removes material in the direction of flow; it will automatically offer a smooth surface to the flow.

Filing is a slow process compared to the various 'electrical' operations. But that is an advantage, not a disadvantage. The goal is not to finish a part in a hurry; the goal is to avoid having to redo it.

Scavenging

My reaction would be that the RSA "model " that took years to develop and had a mile of devil in the details, will work best in any bore - as long as the stroke ratio is maintained.

Thus both the radial and axials could be copied as all you are doing is scaling equally in both directions.

The radial angles set the directions to minimise short circuiting, and the axials maximise the scavenging purity - both together form the loop shape and duration.
Anything other than a square bore/stroke and you have instantly compromised the angle area capability, and all the R & D done by Aprilia is null and void.

Most two-stroke people define radial scavenging directions by quoting the distances where the ports would intersect the center line (the leading distance and trailing distance in the drawing below left). Gordon Blair used that notation in his publications, and 95% of us followed suit.

But there is a better, more universally applicable way.
I will explain with an example, not of scavenging directions, but of port timing: I might say that a transfer port height of 13 mm is perfect for a racing engine. That may be true for a 125 cc engine, but it would be nonsense for a 50 cc.

But if I say that a transfer port timing of 130° is perfect for a racing engine, then that is valid for any engine, regardless of its cubic capacity. Absolute distance values (millimeters, inches etc.) are not suited for universal guidelines. Degrees are, as are percentages of bore or stroke. rpm values are not; mean piston velocities are.

I express transfer duct directions in degrees. Each duct has a leading flank and a trailing flank. Each flank intersects the bore at a point which I can define with a positional angle. And each flank hits the fore-aft center line of the bore with an included angle which I call the directional angle. The drawing below left may clarify what I mean. And the drawing on the right is an example of an existing cylinder (it may be small, 6.5 cc, but it has been unbeatable for over 10 years).

256234256233

Now you can express the radial characteristics of the transfer ports with positional and directional angles, regardless of bore and stroke.
And you can express the ports' axial characteristics with axial angles, but that only holds for engines with identical bore/stroke-ratios, as Wobbly explained.
Your approach of using a height h1 in the cylinder where the transfer port's roof would hit the opposite cylinder wall, is very good, but you need to express h1 as a percentage of the stroke. Then you will have a truly universal value. Then you will also see that short-stroke engines require smaller axial angles.

… now would be a good time to write something about the radial angles of the A-transfers.

Surely a duct with a radial angle of over 20° offers a smaller cross-section to the flow than a duct that enters the cylinder perpendicularly?
Yes it does. But there are two good reasons to angle it upward anyway.

First, perpendicular mixture streams coming from the A-ports would collide and slow one another right down. The upward angles provide for less velocity losses and less
pressure losses, so despite their smaller cross-section, upward ports may flow as much, if not more, than perpendicular ports.

256232

(Now you may well ask why the B-ports do not get the same treatment; that is because the central scavenging column, resulting from all incoming scavenging streams together, must not have too much radial velocity, or the loop scavenging will result in a loop-loss into the exhaust).

Second, there is a thing called scavenging balance (I invented the word for my personal use, so this may well be the first time you ever saw it).
If you looked closely at the scavenging picture of the MB-cylinder I posted earlier today, you may have noticed that the 'radial scavenging directional resultant'
had a value of 101,045°.

90° would have meant 'straight up'; more than 90° indicates that the central scavenging column is leaning towards the exhaust side of the cylinder.
But we don't want that; it is bad for the scavenging of the rear part of the cylinder, and it is risky because it may provoke scavenging losses straight into the exhaust.

256230 256235 256231

But how can we prevent a scavenging column from toppling over to the exhaust side like the leaning tower of Pisa? Not by pushing against its basis, but by pushing higher up. Hence the radial angle of the A-ports. The pictures will tell the story. (If only the Pisa architect had known a bit more about two-stroke tuning....)

the sine of this 'axial scavenging directional resultant' is an indication of the scavenging column's axial velocity. If the column moves too fast in relation to the mean piston velocity, there will be severe scavenging losses; if it doesn't move fast enough, the cylinder will not be completely scavenged.

wobbly

25th January 2012, 14:23

SS90

25th January 2012, 14:23

above answer is obviously refering to Kobas post.

I was going to say he didn't draw in the bridge in the picture which changes things somewhat.

By about 4% in regards to flow (more or less)

F5 Dave

25th January 2012, 14:38

. . .
Then to the dyno - it will do one of five things.
. . . . . - or finally - do nothing which will make any sense.
. . . . .
Fixed that for ya. This is how I first read it & made me laugh & laugh as it often mirrors a trip to the dyno with more questions raised than answered, except on those rare beautiful occasions when progress is made & things work the way they were supposed to.

TZ350

25th January 2012, 17:09

Take a maxed out single Ex port like the one on TeeZees 31 Hp 125 engine - that is blowdown limited by design - Grind the bulges on the top 1/2 of the port, outside the cylinder wall, above the transfers to see if this increases blowdown flow.

Now that is something to look at.

The Suzuki GP's exhaust port angles to one side, interestingly a std Suzuki GP 125 cylinder has a small bulge on the tight side.

255998

The rotary engine guys talk about radusing the edges of the exhaust port for a significant flow improvement, so something else to look into.

Frits Overmars

25th January 2012, 20:05

Would the bulge have a similar effect on a single Ex port ??That depends on the port width. A single port will not be as wide as the total width of a bridged port, so the effect will be less pronounced, but the principle remains the same: each particle of exhaust gas wants to leave the building ASAP and the shortest path is radially outward. Therefore the radial lines from the center of the cylinder bore to the edges of the exhaust port describe the initial shape of the exhaust duct's side flanks.
But the duct volume should be no larger than absolutely necessary, so continuing those radial lines would be counter-productive. As the exhaust duct floor drops, these side flanks can be curved towards each other, keeping the flow cross-area of the duct constant. The picture shows the underside of the duct.

Farmaken

25th January 2012, 20:50

So, my cylinder ( TF 125 Suzuki ) is similar to TZ`s in that the Ex duct turns left as it exits the cylinder and there should be some benefit to be had from opening the duct (not the port ) above the transfers on the long side as Wobbly suggested ???

Ex port is 71% bore Dia
56.5 mm Bore
50 mm Stroke

??????????????

dinamik2t

25th January 2012, 22:24

In MOTA, there used to be a small calculator, measuring exactly the "bridged port radial attitude angle".
Eg for an RS with 32mm arc port width (each) and 3mm bridge, it gives about 37*:
256020

Say TZ's was a bridged port with 0 brigde, it's arc width should be around 48mm - 24mm each. It will be 24.5*.
256021

Well in saying that T ports use the bulge because of the bridge interfering with flow is the obvious answer, and I agree.
But these are bloody 2 strokes we are talking about and very little seems to work in the way you might think at first glance.
I would put the question, and it may be one hell of a discovery if it works.
Take a maxed out single Ex port like the one on TeeZees 31 Hp 125 engine - that is blowdown limited by design - though the small carb may mask the effect somewhat I would say.
Grind the bulges on the top 1/2 of the port, outside the cylinder wall, above the transfers to see if this increases blowdown flow.
Pretty easy to test with a suck thru the Ex port, before and after, on a flow bench, and a piston sitting at the transfer open point.

We might be able to 'semi-test' the effect in EngMod like this: In ExPort, choose Bridged mode and use a zero value in everything describing the bridged port shape. Then sim once with zero side wall angle and once with, say, 20 side wall angle.

I didn't have enough time to run full tests now, but in peak power of a random 56 bore, 0* side wall was at 30.48KW while 20* side angle was 30.46KW. Delivery, efficiency and temps, all the same too.

teriks

26th January 2012, 08:06

--snip-- A single port will not be as wide as the total width of a bridged port --snip--
Except for my 92% single port, that already have such bulged shape. -Sometimes a ringless piston is a good thing :D

We might be able to 'semi-test' the effect in EngMod like this: In ExPort, choose Bridged mode and use a zero value in everything describing the bridged port shape. Then sim once with zero side wall angle and once with, say, 20 side wall angle.
I don't think you will get anything really useful out of any 1D simulator in this case.
You'd need some, at least in my un-epxirienced opinion, very complex 3D CFD calculations coupled to the 1D simulator to get anything that might be reasonable.
-Yes, I'm humbled in that field as well after doing some fluent stuff at work. It's not only EngMod that can have such effect...

bucketracer

26th January 2012, 08:52

So, my cylinder ( TF 125 Suzuki ) is similar to TZ`s in that the Ex duct turns left as it exits the cylinder and there should be some benefit to be had from opening the duct (not the port ) above the transfers on the long side as Wobbly suggested ???

We have some std TF cylinders here at work, later when I get a chance I will dig one out and see how the shape of the exhaust tract compaires to a std GP cylinder.

TZ350

27th January 2012, 15:47

Hi Everyone

3 consecutive weekends racing is completed with me currently sitting in 9th position in the 600 Supersport Championship.

256127

Timaru's Levels Raceway hosted round 2 last weekend 14th and 15th. It rained constantly on the Friday practise day but the weekend was hot and sunny.
Unfortunately the track was very slick however due to a lot of oil being dumped on the first few turns which definitley hindered everyones lap times. After qualifing in 13th position of 20 I certainly wasnt looking forward to the start, trying to make up positions and avoid the oil was a risky combination! It went ok although I dropped a couple of places while avoiding a crashed rider and ended up in 11th place in the 1st race.
Race 2 was going a heap better, I was managing to keep up with some faster riders until my race came to a grinding holt due to a miscalculation with the fuel which saw me run out 3 laps from the end.

It was a weekend of mixed emotions: I was gutted to DNF but happy at the same time that I had been running a better pace and most of all had been thinking of my friend Cam Jones who was seriously injured Sunday morning. He is still in Intensive Care. Please keep him in your prayers and keep an eye out on Trademe for items being auctioned with the proceeds going to a fund for Cam.

The 3rd round was held in Invercargill this past weekend. I couldn't wait to ride one of my favorite tracks ever on the CBR600! Qualifying left me in grid position 9 - far better than the previous two rounds which gave me a boost of confidence. I ended the 1st race in 9th with a seriously torn tire. It was good experience for me to ride with the rear moving around so much and feel how the bike behaves with deteriorated rubber.
Race Two and Invercargill weather did its thing in time for me to go around the outside of a few people at turn 1 putting me in 4th position. I held on to 4th for a few of laps until I began to struggle to see with my visor fogging. It was my fault for not sticking the pinlock antifog strip in properly but I was still happy to finish in my highest placing this year of 7th.

Huge thanks;
to my team - Jamie, Scott, Georgie, Shannon, Travers and especially mum and dad - for all their hard work and making it a fantastic few weeks. I cant thank Jamie enough for getting me out there this year.
to Pete Finlay, the Castrol Honda boys and Blue Wing Honda for all the help and support I could ask for.
to my sponsors and supporters - Baywatch Motor Lodge, please stay here when you are in Timaru, Uncle Geoff and Aunty Gay, Race Pace Trainers, Deep Web - Web Design, Blue Wing Honda, HJC helmets, Sidi boots, NGK spark plugs, Tridon Toledo Tools, Carcolors, Bearing Wholesale, Metzeler tyres and Total Oil.
And finally to all the other riders for the great racing and making our sport awesome to be part of.

My next championship race will be the 4th round at Hampton Downs on March 17/18th. We will also use the Pacific Club race meeting at Taupo in February as a shake down for nationals there late March.

256128

Until then, Avalon.

Rick 52

27th January 2012, 20:03

Cheers Rob for sorting out my ignition timing and the advice on my port timing !! you guys know what you are doing ..Its a joy working with people that know their stuff :yes::yes:

dinamik2t

28th January 2012, 09:46

TeeZee, would you mind telling what type of stator-rotor do you use? Would it be a typical full size flywheel, an internal rotor ??
Do you have any experience to judge which of the two would be better for such an application?
I remember RS's had a typical -heavy I guess- flywheel.. On the other hand all RSW/A's I 've seen through photos had internal rotors. :confused:

TZ350

28th January 2012, 10:01

Yes the Honda RS125 does have much heavier crank wheels than the Suzuki GP125. But the Honda uses a light internal rotor so I am not sure whether my light crank wheels and heaver flywheel in total are more or less heaver than the Honda, about the same is my guess. I remember (hopefully correctly) a comment by Wobbly that a heavier crank helps extend the over rev.

256159 Later KX80 Ignition

This is the flywheel and stator plate and pickup I am currently using with my Ignitec, At the moment the high voltage charging coil has been removed, later I want to re-wind it for charging the 12V battery so it is no longer a total loss system.

wobbly

28th January 2012, 11:14

Early RS125s had an external rotor the same as the CR125 it was derived from.
The later GP only RS125 engine had an internal rotor about the same as the RSW/RSA with a much higher inertia crank assy.
When changing to total loss and removing the small rotor, the engine had no overev at all.
So much higher inertia cranks were made by VHM and the factory for this application.
The RSW/RSA crank inertia is very high due to full circle and plated wheels and added Mallory, to be able to run with the small rotor assy.
It matters not where the inertia comes from - the wheels or the rotor create overev by reducing the in cycle speed variations of the crank assy, at the expense of outright acceleration capability.

dinamik2t

28th January 2012, 11:59

I see.. You must be refering to this post http://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner?p=1129962007#post1129962007.

I had the exact same generator off ebay!
I recently purchased another generator - inner rotor type. It comes from an IAME x30 kart engine, it's called Selettra Digital -K(ey). It must have been used by aprilia, because there was a pic in Frits files, with that generator on an RSA.:scratch:

256173

I haven't had the chance to test neither one (actually I don't know how to connect the selettra one. it has an 8-wire connector, none of which I know the use).
Actually, most kart engines seem to use the inner rotor type. Can't logically process the reason.

edit: thanks for the hint Wob!

crazy man

28th January 2012, 14:56

where do you guys get ya cams ground? what kind of grinds are you getting on your fxr 150's?...ie factory stuff or guess work ?

Buckets4Me

28th January 2012, 15:00

where do you guys get ya cams ground? what kind of grinds are you getting on your fxr 150's?...ie factory stuff or guess work ?

just used the angle grinder on my one :scooter:
made a good job and goes faster now

but on a positve note ask richban (or my guess kelford cams?)

crazy man

28th January 2012, 16:00

just used the angle grinder on my one :scooter:
made a good job and goes faster now

but on a positve note ask richban (or my guess kelford cams?)oh well you should go faster than kelford cams one if you have done that lol

husaberg

28th January 2012, 16:31

I see.. You must be refering to this post http://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner?p=1129962007#post1129962007.

Actually, most kart engines seem to use the inner rotor type. Can't logically process the reason.

edit: thanks for the hint Wob!

I can't vouch for this being correct, but he the (Author) was a designer/etc for Cosworth.(Ignition bit)

The other bit is for Grumph we mentioned a while back this guy i certainly never knew he would go to the evil side i guess he is in a way responsible for the Evil FXR150 as Well.
He knew Bugathi as well as co designing the TSCC.
http://docs.google.com/viewer?a=v&q=cache:D5LvEZT9e7YJ:twinspin-ec.com/The Piatti Story_MASTER_Word_02.pdf+patents+for+vincent+piatt i&hl=en&gl=nz&pid=bl&srcid=ADGEESgVOzV8mu0AmIn5ZXdBdPiHpb16eWG0jNGU8qa2 Gb1Kd86ZYlojR3yeSMvOSMMk_CyB1s1lKgOWBi1yZeznOyq2My BOvc5S7XO9hIKF0M7HwNi_FfNUBJBbBaAHfAy2k_3Lk_sg&sig=AHIEtbTx5y12z-YhH3gOMYEJKo7N4HUBhA

http://twinspin-ec.com/Analysis Software.htm

After that, it seem redundant to mention that the AMC motors referred to were actually made in France by an outfit coincidentally called AMC....so blame the French again, this time for wob's early sexual adventures.....

I would be interested in seeing his AMC variable exhaust Exhaust "Bazooka" patent.

husaberg

28th January 2012, 21:52

I don't know if his design for the injection went anywhere or if the design was loaded with too much baggage.

In the same mag as the last one.

There is a real bad joke elsewhere in the Mag that said the Cagiva chief George Vukmanovich was, by then sick of Cagiva and was trying to get a Job with Ron Haslam and Serge Rosset who were at the at "ELF" team.:facepalm:
The original experimental Honda powered GP bike
Randy and Kenny i believe made up as i think Randy used to later on pilot the Twin seat YZR500.
There is also no truth in the rumor that Dave is in fact taller than George.

richban

29th January 2012, 09:21

oh well you should go faster than kelford cams one if you have done that lol

Oh harsh. Can't have you bagging my sponsor / family. Hey I will swap you a set of proper good Kelford race cams for a set of them aprila sxv cams you got lying around.

crazy man

29th January 2012, 09:29

Oh harsh. Can't have you bagging my sponsor / family. Hey I will swap you a set of proper good Kelford race cams for a set of them aprila sxv cams you got lying around.lol even better you could donate that rsv550 engine to me !

richban

29th January 2012, 09:40

lol even better you could donate that rsv550 engine to me !

Funny guy. Its an rvx550. Hence the need for some new cams. Maybe I should sell it. Gunna be a while before I have the dosh to finish the project. Was thinking I would sell the engine and Honda RS250 roller and buy a dirt bike.

crazy man

29th January 2012, 12:56

Funny guy. Its an rvx550. Hence the need for some new cams. Maybe I should sell it. Gunna be a while before I have the dosh to finish the project. Was thinking I would sell the engine and Honda RS250 roller and buy a dirt bike.CSL are doing a guys fxr motor for l guy in auckland.. useing the standand fxr cam grind. on my old dyno that people said it read low my mates one put out 19hp just with the cams and exhaust did not get around to putting the high com piston in it. l still have it.. was told the kit was rated for 23 hp with no port job

richban

29th January 2012, 14:48

CSL are doing a guys fxr motor for l guy in auckland.. useing the standand fxr cam grind. on my old dyno that people said it read low my mates one put out 19hp just with the cams and exhaust did not get around to putting the high com piston in it. l still have it.. was told the kit was rated for 23 hp with no port job

Sounds about right. I think my bog standard engine was 17.5 with carb and exhaust change. What Kit? Is there a kit?. 20 seams easy to get on an FXR its the other 6 or 7 that come hard.

Doing a nice job of hijacking the 2 stroke thread here well the boys are at the track. Sorry Lads. Hope you all had a good day racing.

crazy man

29th January 2012, 15:06

Sounds about right. I think my bog standard engine was 17.5 with carb and exhaust change. What Kit? Is there a kit?. 20 seams easy to get on an FXR its the other 6 or 7 that come hard.

Doing a nice job of hijacking the 2 stroke thread here well the boys are at the track. Sorry Lads. Hope you all had a good day racing.yip there is a factory race kit. cams ,piston, exhaust , rear sets , stearing damper lol .l have the hole kit but not the exhaust . my engine in stock was 14.3 hp what was your one stock? it may tell the dyno diffence? sorry 2 smokers you lot will be to busy fixing your bikes up to look in here for a week or so lmao

richban

29th January 2012, 16:03

yip there is a factory race kit. cams ,piston, exhaust , rear sets , stearing damper lol .l have the hole kit but not the exhaust . my engine in stock was 14.3 hp what was your one stock? it may tell the dyno diffence? sorry 2 smokers you lot will be to busy fixing your bikes up to look in here for a week or so lmao

Never had it on a dyno bog stock. Had a 28mm flat slide and a shorter exhaust only. Have run a PWK30 and they work well for a 2 stroke carb. Nice and easy to tune. I would be interested in seeing that piston. Has it got really big valve pockets. Like 4mm deep if so I want one.

husaberg

29th January 2012, 17:18

yip there is a factory race kit. cams ,piston, exhaust , rear sets , stearing damper lol .l have the hole kit but not the exhaust . sorry 2 smokers you lot will be to busy fixing your bikes up to look in here for a week or so lmao

If he (Crazy man) is allowed a factory race kit.
well then it is only fair if i have one as well.
OK HRC do do one they call it an....er..... RS125.

256256

Should be a easy fit into a RS125 frame:innocent:

256254

On a more serious note i seen these today Yummy A rear disk valve Honda RS125 The japanese are still copying the Italians.
The other is a billet cased std configuration.

it is here
http://www.ekartingnews.com/viewtopic.php?t=97465

husaberg

29th January 2012, 19:37

These are on the same page as above.
http://www.ekartingnews.com/viewtopic.php?t=97465

TZ350

29th January 2012, 20:02

256275

Whow look at that rotary valve conversion, thanks Husaburg

TZ350

29th January 2012, 20:49

EngMod2T

There have been a few very informative postes lately that have got me thinking.

256278 256280

As we were on the subject of scavenging angles, now would be a good time to write something about the radial angles of the A-transfers.......

Like Frits explination of the leaning tower of Pisa and scavenging angles and how the front transfer ports are used to support the rear ports.

And the vital percentages in pipe design, Frits mentioned that things had to be held within certain % limits and Wobbly gave more detail of this % aspect of pipe design and something of its importance.

256279

EngMod2T displays these vital % values in the pipe picture.

If I were to explain pipe design I would need to write a book, but in general things are pretty straightforward in relation to the % values.

End of header is always 31 to 33%

And end of diffuser is always 62 to 68%.

To see the effect of a silly long header, you can watch the pressure ratio at the Ex port, and thus the effect this has on the depression in the cylinder.

We are looking for the lowest and widest negative ratio we can get around bdc when the transfers are fully open.

A long header delays the beginning of the depression too late in the cycle, when in the power band.

In a race 2T we are always fighting power range Vs peak power.
Shorter diffusers create steeper angles, thus greater wave amplitude, but this narrows the effective band width.

So - in general the best compromise is around 66%

The % I quoted for header means that portion of the length from piston to rear cone end.
It’s from the piston to the beginning of the diffuser, what happens in between isn’t relevant.

Unless of course you use a small Ex duct and a bigger header, that makes more power.
And of course same for the diffuser end, that is simply 66% of the length from the piston to the end of the rear cone.

These little teco insights are very much appreciated......

This whole thing has got me thinking about making a new triple exhaust port cylinder liner, not so much for more power but to do away with the 75% exhast port and gain some extra mechanical reliability by reducing the width of the main exhaust port window.

And also by getting the transfers low and wide I might be able to reduced the exhaust duration from 203 deg to something closer to 196 which if I remember correctly, is the ideal as it stays in resanance with the pipe for longer giving a wider spread of power.

And at the same time re-arrange the transfer port layout so the bulk flow comes from the rear ports and the smaller front ports are used to support the scavinging column.

2T Institute

29th January 2012, 22:45

256254

On a more serious note i seen these today Yummy A rear disk valve Honda RS125 The japanese are still copying the Italians.
The other is a billet cased std configuration.

it is here
http://www.ekartingnews.com/viewtopic.php?t=97465

That is a kit from the Italian company CRP :laugh:

husaberg

29th January 2012, 22:58

That is a kit from the Italian company CRP :laugh:

is it:Oops: Who said Irony is wasted on the Aussies:laugh:

:innocent::facepalm:
256286256287256288256289
http://www.crp-racing.com/portal/en/kit-honda-disco-rotante.html

Yow Ling

30th January 2012, 05:17

is it:Oops: Who said Irony is wasted on the Aussies:laugh:

:innocent::facepalm:
256286256287256288256289
http://www.crp-racing.com/portal/en/kit-honda-disco-rotante.html

From the CRP website "Use of innovative technologies like Reverse Engineering" isnt reverse engineering a flash way of saying copying?

TZ350

30th January 2012, 06:50

From the CRP website "Use of innovative technologies like Reverse Engineering" isnt reverse engineering a flash way of saying copying?

Yep the inovative Italians copying the Japanese ......

...... "world domination of bucket racing with a fleet of MB powered buckets" - Gary got a 3rd and 1st today on his and I don't think he was trying too hard. Only a playday though. Tokoroa should be fun next weekend with both Gaz and Dave M riding, and Rick though he has some pussy Suzuki motor.

The 4-Stroke boys might have to get their skates on. 256290

SS90

30th January 2012, 07:44

Well in saying that T ports use the bulge because of the bridge interfering with flow is the obvious answer, and I agree.
But these are bloody 2 strokes we are talking about and very little seems to work in the way you might think at first glance.
I would put the question, and it may be one hell of a discovery if it works.
Take a maxed out single Ex port like the one on TeeZees 31 Hp 125 engine - that is blowdown limited by design - though the small carb may mask the effect somewhat I would say.
Grind the bulges on the top 1/2 of the port, outside the cylinder wall, above the transfers to see if this increases blowdown flow.
.

I think I may have posted some old images of the first bridged exhaust ports I made quite some time back. In there somewhere I there are one with these bulges, for the same reasons you have outlined.

Many guys running unbridged ports use this method over here.

I found when you grind the "bulges" in an existing port, you definatley get measurable gains, (up until a point). Much like alot of aspects of 2 strokes, such things only make gains when it is restricting something. After this point, I have seen no gain.

I have never put this on any sort of flow bench, but the numbers on the dyno rolled the right way.
When I increased blowdown time area by increasing duration (as I was fearful of cylinder studs after a misadventure), these bulges, while useful on one time/area combo (lower duration) proved absolutely no gain what so ever on one that I would have thought superior.

I have found that with limited gear ratios and air cooling, 191 degrees of exhaust duration has been the best compromise for me......(get your time area through width) as if it won't "pull the top gears"..... it doesn't matter a toss what the max HP is, as an engine putting out 20% less power will whip ya ass, just by virtue of the fact that it can actually drive out if the corner. Overrev or not.

rgvbaz

30th January 2012, 08:29

Anyway, I've asked my dad to have go at translating Frits's article. It's been 44 years since he moved back from the Netherlands where he lived for 8 years. Not sure how he will get on with the technical bits as he grew plants out there, he did say he used to think in Dutch in his mind, when he first came back home he had to translate the English word to Dutch for a while so his Dutch was good but 44 years is a long time.

Anyway, I will email it to him and he will see what he can do.

Cheers

Dave

I spoke to my Dad tonight, 44 years is a little to long for him plus most of the technical words he wasn't familiar with. He could read the intro which talked about how Frits got into tuning bikes but then it got all technical. He said the hardest part for him is that he never translated what he read and spoke in Dutch to english as he understood in Dutch, which has made it even harder for him to translate back 44 years later.

I hope one of the other guys having a look at a translation has got a little further.

Sorry.

Dave

gamma500

30th January 2012, 09:07

What kind of porting tools do you guys use for 2t cylinder porting? Do you prefer electrical tools or air tools? I'm asking because I've been planning of buying better porting tools, at the moment I dont have proper tools for transfer port modifications...

TZ350

30th January 2012, 11:15

What kind of porting tools do you guys use for 2t cylinder porting? Do you prefer electrical tools or air tools? ...

256303256304256306

Team ESE have managed very good results using basic hand tools. Persionaly I have produced 31 rwhp with about a 4k power spread from a 125cc air cooled rotary valve single exhaust port 2-stroke running a 24mm carb. Even on the world scene this is probably not a bad effort considering its been achieved using the engines original 1970's cylinder.

256305

With these basic tools I have even managed to cut in aux, side exhaust ports, but we have not yet tried this cylinder properly.

256301

With my earlier engine I had a very flat torqe curve about 3k wide

256302

At 31 rwhp (est 34 crank) not so flat a power spread, but I expect that I will improve it with a bit of development.

We posted our results a while ago and no one has suggested that there have been better in the past, and there are still plenty of old hands around who would know.

31rwhp and 4k power spread was achived with a single exhaust port and is pretty much the best ever for a Bucket engine in the history of miniture road racing here in NZ, although there are a few more high hp 2-stroke engines in the pipe line around the country which should hit the tracks soon.

I still have the tripple port to try but according to simulations done with EngMod2T, to get the best from it I need to improve the inlets STA.

I owe my success to reading widely on the net and everything I can get my hands on, making good use of simulation software and listening to "real" industry people and friends who know what they are talking about.

So there is a lot you can do with just basic workshop hand tools, a bit of reading, net searches and if your budget streches to it, some simulation software.

F5 Dave

30th January 2012, 11:18

Think someone posted this place for RA tools earlier & I'd bookmarked it but not stumped up the readies.

http://www.ccspecialtytool.com/182a-mc-small-right-angle-handpiece-adapter

dinamik2t

30th January 2012, 12:16

Think someone posted this place for RA tools earlier & I'd bookmarked it but not stumped up the readies.

http://www.ccspecialtytool.com/182a-mc-small-right-angle-handpiece-adapter

Yes, that's it!

I would prefer the electric grinders. I think they are more torquey than air'ed. Plus, rpm's of the 100,000 size are an overkill in porting. No more than 15,000-20,000 will be needed.

Firstly, it's the shaft motor - 1/3 or 1/4hp is ok. Then there are the handpieces and lastly the cutters. Carbide burrs, diamond coated, abrassives, rubbers.. those are some stuff to look for.

A medium quality motor would cost about 80$ from ebay. Best quality might be Foredom, but I favorise Wecheer!
The straight handpieces cost about 50$ each. The right-angle can be found only from CC (less expensive dealer) and it's quite expensive at 280$.
Cutters' and abrassives' value is dependant to their quality - meaning mostly duration over time. I have got most of mine from ebay at low costs. They're ok and still cut decently after 2 years.

Here, some links (random shops):
> http://www.traditionalwoodworker.com/1_3-HP-HD-Flexshaft-Power-Carver-Foot-Speed-Control/productinfo/247-3301/
> http://www.traditionalwoodworker.com/Slim-Detailing-Hand-Piece-with-3-Collets-by-Wecheer/productinfo/247-26511/
For aluminium > 3mm http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&_trksid=p3984.m1436.l2649&item=230645199118&viewitem=&sspagename=STRK%3AMESINDXX%3AIT#ht_2227wt_1110
...................> 6mm http://www.ebay.com/itm/5-Pcs-per-set-10MM-Tungsten-Carbide-Rotary-Burr-1-4-Shank-/380384790937?pt=LH_DefaultDomain_0&hash=item5890b34999#ht_1370wt_1110
For iron > 3mm http://www.ebay.com/itm/Charming-1set-Tungsten-Carbide-cutter-Rotary-burr-1-8-shank-Gracious-/290630667406?pt=LH_DefaultDomain_0&hash=item43aaf00c8e#ht_1964wt_1110
...........> 6mm http://www.ebay.com/itm/5-pcs-10MM-Tungsten-Carbide-Rotary-Burr-SET-1-4-shank-/120487410216?pt=LH_DefaultDomain_0&hash=item1c0d9bfa28#ht_921wt_1064
DIamond coated > http://www.ebay.com/itm/30pc-Diamond-Burr-Point-Set-Rotary-Tool-Die-Grinder-/180750845732?pt=LH_DefaultDomain_0&hash=item2a15970724#ht_768wt_1110

You could add a set of abrassives too (http://www.artcotools.com/images/cache/AKC_-2_jpg_76deb4c5e221344dd02bcf00715b1882.jpg) and a few Cratex rubbers.
I made my 'collection' over a 2 years period, but it's ok.
Anyway, you get the idea. If you search for the keywords, there are tons of stuff. :)

dinamik2t

30th January 2012, 12:47

(double-posting to make it easier to read)

I hope I didn't sound much like a pro in the previous post - I am just a semi-experienced amateur with porting tools and what I said came from that little experience.:sweatdrop

Some side notes with porting & tools.

If you want to do a port job on a cylinder, first measure its current state. I like to use a nice vernier caliper with at least 0.05 accuracy and a dentist's angled inspecting mirror to accurately determine port roofs - looking/measuring from above the plane of the ports can be misleading and half a mm can make a lot of difference!

256310

Another usefull thing is to use a vernier caliper -with a stop- straigh on the liner. But you will have to cut the ID measuring teeth and a part of the OD teeth too to fit in a 54mm bore. Carefully on the port's roof edge, so that roof angle won't intefere. Always measure many times and take the mean value.
VERY IMPORTANT: measure as accurately as possible and mark the 4 points of the two planar axes (not this (http://t1.gstatic.com/images?q=tbn:ANd9GcQfcCZP8k4vU5nlJBmoBu8Pj6QtndXsw CRDnEpaPc-gSkWPE7sE) kind) on the liner. ie 12 o'clock in the middle of the ex (or in) side, then 3' 6' and 9' accordingly.

After you have decided what you want to do, you must draw everything on paper.
I am into perfection and I like to use a diabetes to design any new radiuses. Then I use a piece of thick paper or even better plastic and cut out the ports' shapes. That is to use it as a guide, exactly into the cylinder. Draw a vertical alignement line in the center of the Exhaust, to match it with the cylinder mark.

256311256313256314

Greatly helps minimize mistakes and cut staight lines!
Always stop before your line ofcourse and do the finishing on a lower speed and a less metal-removing cutter (never actually done that, but it's eh.. a good advice).
I would like to try on thin metal sheet sometime. Even though it will take time to cut the desigh, it will give better accuracy in measurements and cutting.

The most difficult part is with the right-angle ofcourse. When shaping both axial and radial angles! I still haven't figured a good and accurate way to do that (+-5 degrees by hand can be achieved -I believe), but I have something in mind. I'll share it if I ever try it.

Finally, each time you're done with a part of the porting, you can pour some vinamold into the ducts and see what you've done. Helps checking volumes, shapes, radiuses, even angles - but it can't be used to measure as it's not very stable.

Here's a lame porting vinamold for demonstration purposes only! :P

256312

p.s. never forget a mask for your eyes (only) and some cotton for your ears.

kel

30th January 2012, 12:52

The 4-Stroke boys might have to get their skates on.
Skates are on and ready. Believe Gavin, Grant and possibly Tim have theres on too. :drinknsin

TZ350

30th January 2012, 13:43

Skates are on and ready. Believe Gavin, Grant and possibly Tim have theres on too. :drinknsin

It should be a good day, might have to come down for a look.

TZ350

30th January 2012, 13:47

... I am just a semi-experienced amateur with porting tools and what I said came from that little experience.:sweatdrop ...

I am impressed with the way you go about it and love the tools you have, looks like you do a very good job of the ports.

Leed

30th January 2012, 15:32

Mark Jordan's tool for cutting horizontal ports (in a KR-1S)....

256332

The chunk of steel above the tools and in front of the barrel has been designed to slide into a barrel.
Mark can lock it off at any length and use it as a guide so that all ports are the same height.
Also if the grinder slips it reduces the chance of damaging the plating.

a modification to that cylinder insert would be a step to allow vertical cuts (or an angle step - for angular port edges)

husaberg

30th January 2012, 15:58

Think someone posted this place for RA tools earlier & I'd bookmarked it but not stumped up the readies.

http://www.ccspecialtytool.com/182a-mc-small-right-angle-handpiece-adapter

Reciprocating tool (Below)
This will be old hat to the pros no doubt but cool measure 10 times cut once though. (Measuring twice would be ok for most people Not Me I am not that accurate)

TZ had some pics way back with rlffler files bent to suit i guess the idea was from tuning for speed.I will post when i find them

Today Tomas spent the afternoon looking at one of the spare barrels.

Pic-1 Tomas is blueing the barrel so he can mark the port heights.
Pic-2 the Honda RS125 Specs.
Pic-3 Tomas has used a degree wheel to set the piston position in degrees ATDC he wants and is scribing a line to show the correct port positions.
Pic-4 working from the top he cuts the port edge up to the line Pic-5.
Pic-6 working inside with a dremmel and riffler files bent to the finished angle of the port he blends the port edge back to the transfer duct to achieve the port (axial) upswept angle of 30 degrees for the main transfers that he wants.

There was surprisingly little metal removed but it was slow careful work it will take the rest of the week or so to complete it. Tomas says it,s most important to get the ports symmetrically even.

The other area to pay attention to is the MSV for combustion chamber turbulence and combustion dynamics and unmasking the transfers.

.

F5 Dave

30th January 2012, 16:20

yeah but cleaving the cylinder in twain makes the ports childsplay to get at. glue it together afterwards?

crazy man

30th January 2012, 16:26

my mate a jeweler made the nice's job of porting l'v ever seen. it ashame he did not know the port timing of what he was doing

kel

30th January 2012, 17:29

husaberg

30th January 2012, 18:02

I have a couple of sets of riflers bought off ebay,
256337
seem to sit filing for hours for just the smallest change. Prefer the dremel and carbide bits, they have a 90 deg head but it wont fit in a 50mm bore. :no:
Husaberg, Giggles does actually have a dentist drill, not sure if it came from the back of a German car though:lol:

I ve got some Dentist bits if he wants them, l but they are tiny they would be more useful for drilling small items like teeth. :sweatdrop

Desaxe

I asked the panel a while back about offsetting cylinders ala YZF450 and Scott and Kawasaki ZX10R.

What i didn't know it comes from the steam age and a lot of aero engines were like this this is what i came up with today whist looking for something else.
I am still trying to model this with a 50mm 50 engine to see the results as my maths is crap and drawings are proving inaccurate.

http://en.wikipedia.org/wiki/Desaxe

A desaxe engine, in engineering (usually automotive, but also steam engines (http://www.kiwibiker.co.nz/wiki/Steam_engine)), means one in which each cylinder (http://www.kiwibiker.co.nz/wiki/Cylinder_%28engine%29) is not positioned with its exact center (the bore axis) directly above the centerline of the crankshaft (http://www.kiwibiker.co.nz/wiki/Crankshaft); instead, the cylinder is offset slightly. "Désaxé", in French, means "unbalanced"; it is not (despite remarks to the contrary) the name of the inventor of French origin.

If the offset is in the direction of rotation, it has the effect of increasing the leverage (http://www.kiwibiker.co.nz/wiki/Lever) applied to the crankshaft during the "power" stroke, and reducing thrust wasted against the cylinder wall.
It also distorts the duration of the four strokes (http://www.kiwibiker.co.nz/wiki/Four-stroke_engine), or cycles of combustion. In a conventional engine, each of the strokes (intake, compression, power, exhaust) is nominally 180°, totaling 720° for the complete 4-stroke combustion cycle (http://www.kiwibiker.co.nz/wiki/Four-stroke_engine). A desaxe engine adds to the duration of the two downward strokes (intake and power), and subtracts the same amount from the two upward strokes (compression and exhaust), with the total remaining 720°. A typical desaxe engine will have events timed 185° - 175° - 185° - 175°, etc., with the differential roughly (but not directly) proportionate to the percentage of offset distance to stroke length.
The relative proportion of offset distance vs. stroke length ranges from very small to almost 20%; viz. an engine with an 80mm stroke may have a cylinder offset of 20mm.

http://ashonbikes.com/content/d%C3%A9sax%C3%A9-engines

Kawasaki’s new ZX-10R Ninja is bristling with state-of-the-art and new technology, but like so many ideas, some can trace their roots back a very long way. The Ninja’s engine uses a désaxé layout, which means the centre line of the cylinders is offset, and rather than crossing through the centre line of the crank as on most engines, it passes 2mm in front of it, on the exhaust side.
Horex VR6
Just like the crossplane crankshaft in Yamaha’s R1, this is an ‘innovation’ which was being used by the Victorians in their steam engines before the first petrol engine was ever thought of. Where the crossplane is designed to produce a more constant crankshaft speed, désaxé engines aim at giving the pistons an easier life.
During the power stroke, the cylinder pressure is forcing the piston down the bore, but the conrod is at an angle to it. This means the piston is being forced hard against the side of the bore, which every engine builder will know about as there’s always a lot more wear on one side of the bore and piston than the other. By shifting the cylinder to one side relative to the crank, the conrod’s angle with the piston is reduced during the downward power stroke, and the sidethrust is reduced with it.
This has two useful effects: one is a reduction in friction, improving the efficiency of the motor. The second is that because the peak forces on the pistons are smaller, they can be lighter, which in turn allows for lighter conrods and smaller bearings, also reducing internal friction.
Désaxé is often written De Saxé or something similar with claims made that the idea was invented by a Frenchman of this name. This is not the case, and it’s unlikely as one meaning of désaxé is a deranged person – roughly translated it means nutter! The other meaning is off-centre, which describes this cylinder arrangement.
There are other consequences. A small increase in the stroke compared with the crank throw has to be accounted for at the design stage. The power stroke takes longer, which is good for a high revving engine as it allows more time for efficient combustion, but it also makes controlling vibration more difficult as the secondary out-of-balance forces become more complex and asymmetric. The 1970s Hesketh V-twin used a désaxé design which was largely responsible for that bike’s excessive vibration, and the new VW VR6-derived Horex engine is also désaxé, although for packaging reasons rather than to deal with piston sidethrust.
The Ariel Leader two-stroke achieved désaxé advantages but by using gudgeon pins offset in the pistons – the cylinders were still centred directly above the crank.

http://www.iroquois.free-online.co.uk/merco/len.htm

The piston is of typical design, with a nicely filleted baffle and the lower third of the skirt relieved approximately 0.0005 in. The gudgeon pin is of 3/16 in. dia., fully floating, with brass end pads A drop-in cylinder liner, flanged at the top and having a wall thickness of 0.054 in., is used. The flange fits in a channel in the cylinder head, which is of a hemispherical pattern with centrally located long-reach plug and is held down with six screws.
The port timing of the Merco is fairly conventional, except, of course, for the fact that, in terms of crank angle, the opening and closing of the cylinder ports, due to the Desaxe layout, are not symmetrically disposed either side of b.d.c. The actual effect of this is that the ports open and close about 5 degrees later in the cycle, while the piston velocity is speeded up during the compression stroke and slowed down during [lie power stroke, thus giving more time for the expanding gases to do useful work. Rotary valve timing ts normal, with a total induction period of about 185 degrees.

And this
http://hellforleathermagazine.com/2010/12/free-power-offset-cylinders-explained/#more-13281

256340

We’ve been reading a lot about offset, or désaxé, cylinders this year, they seem to be the flavor-of-the-month for motorcycle engine technology, helping to explain the unprecedentedly high outputs from bikes like the 2011 Kawasaki ZX-10R. But, we’ve been unable to translate the relatively simple concept into anything less than very complicated words. This drawing does that for us. As you can see, the design locates the piston to the side of the crank centerline, creating a straighter path for the connecting rod during the power stroke and reducing its sideways force on the piston as it slides up and down in the cylinder. This means less frictional losses and an easier life for the pistons and rods, which can be made lighter, thereby reducing reciprocating mass. That helps the Ninja make a record 197bhp, but bikes like the Honda CBR250R and even the Horex VR6 benefit too.
And more curiously this on the Bantam thread.
http://bsabantamracing.editboard.com/t773-de-saxe-engine-configuration

Hi all,
Mick gave us some good all round info on this old chestnut and the Phil Irvine piece from the late 60s is spot on ,as far as it goes .
To get bang up to date, some investigative work done to the Aprilia RSA125 engine suggests that the concept is not worth the hassle.
There is no question that rod angles become assymetric , but the benefit is negligible on this engine so a Bantam would`nt feel it !
Less obvious is the increase in piston stroke against the crank stroke indicating that from tdc to bdc is more than 180* and from bdc to
tdc is less than 180* . This then begs the question , just where is tdc ? All of this was arrived at using an offset of 10% of the 54.5 stroke .

Confused ? So am i .

Have a good 2012 , regards Trevor

not sure what you are trying to tell us Mike, but before we move on from this subject,I would like to clarify what we are saying
it does not produce any more power ?
more importantly it does make better or more effective use of the current power you are producing ? .
adding one point to the RSA 125 point trevor noted, an aquantance of mine said they only dropped it because they were told to! and it was somthing to do with the increased friction at higher RPM apparently needed to much cost /time - and the potential that it cancells out the advantages at higher rpm because of the extra friction.

! But he who should be listened to, said there are possibilities for engines only running to 10,000 and with a low number of gears. !

regards Derek

Can Frits add some info to the RSA bit of the story?

(http://www.iroquois.free-online.co.uk/merco/len.htm)

(http://www.iroquois.free-online.co.uk/merco/len.htm)

koba

30th January 2012, 21:33

With these basic tools I have even managing to cut in aux, side exhaust ports, we have not yet tried this cylinder properly.

Freaky. All those tools look so familiar, almost all of them are identical to ones in the workshop I use. Even the oil can looks identical.

Frits Overmars

31st January 2012, 00:33

...Can Frits add some info to the RSA bit of the story?I can, and I think I did. But I haven't discovered a forum yet where I could get along with the search function. Entering 'offset' just got back to me with 'Sorry - no matches. Please try some different terms.' So it will be up to you to (re)find what I wrote about it.

EDIT: found it after all: http://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner/page392 , 27th December 2011 04:04.

Frits Overmars

31st January 2012, 00:42

Some side notes with porting & tools.... Always measure many times and take the mean value.Suppose you measure the same dimension five times; four of them exact. Then taking the mean value is guaranteed to give you the wrong answer :D.
My way: measure five times, throw out the upper and lower extremes and then take the mean value.
But your next remark more than made up for everything:
p.s. never forget a mask for your eyes (only) and some cotton for your ears.:niceone:

dinamik2t

31st January 2012, 05:24

I am impressed with the way you go about it and love the tools you have, looks like you do a very good job of the ports.

Many thanks TeeZee! I sure enjoy doing the stuff, if not anything else!

Suppose you measure the same dimension five times; four of them exact. Then taking the mean value is guaranteed to give you the wrong answer :D.
My way: measure five times, throw out the upper and lower extremes and then take the mean value.

Yes, I do reject non-logicaly-valued ... values! Thankfully, -I think- I learned the method of measuring and calculating different kind on deviations quite well from university - I 'm very proud of it :p
Let aside the silly fun part, it is really important to know a few basics about measuring stuff and take into account possible error sources. Especially on mass production engines, you could measure a width with 0.01mm accuracy and be very happy - but manufacturer would have positioned the X part in the engine with, say, 0.05mm accuracy and all your measures would be crap.
Or here in porting: make a mark on the paper to draw a line with 0.1mm accuracy, but neglect the fact that the pen's nose is 0.7mm, the knife produces another 0.5mm inaccuracy and that by hand porting tools, you can cut with 0.5mm accuracy. :laugh:

But your next remark more than made up for everything
Hold on :wait: If the mean value is only one point you disagreed with, by 'everything' I take it you had more complaints with that post, eh?
:doh:

F5 Dave

31st January 2012, 09:08

groan, rings true and loud some of above. Was up late last night pulling my GasGas dirtbike down. To complicate matters, I can't help myself & while it was down being freshened up (& looing for an errant noise) I have to correct the squish clearance which is at 1.9mm. At least I think it is, my thickest solder is 2.0mm & I'm sure I can measure the flat.

either way I have to complicate the matter by measuring the comm & it is very easy to get lazy, but I pushed myself to measure it 3 times. Sure enough the 1st & 2nd measurements were miles apart. But then came them comedy of tired errors, measuring & then discovering the headbolts weren't done up, just resting on the o-rings as I had left them to tighten after letting the oil in the burette settle, but forgot. And the next time I got it all down & had forgotten to record what number I started out with. Sigh, take apart, clean out, reassemble repeat. Again & again. 3 times became about 7.

Heck & this is on a 300cc barrel, the margin of error is huge compared to my 50. - that takes some careful attn with only ~3cc head.

husaberg

31st January 2012, 15:55

I can, and I think I did. But I haven't discovered a forum yet where I could get along with the search function. Entering 'offset' just got back to me with 'Sorry - no matches. Please try some different terms.' So it will be up to you to (re)find what I wrote about it.

EDIT: found it after all: http://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner/page392 , 27th December 2011 04:04.

Sorry Frits here is your answer here
.....I would not bother with offsetting cylinders or piston pins to achieve asymmetrical timing. The effect is very small and who needs the complication.
The pic below shows a calculation I did on the Aprilia RSA125. I gave it an offset of no less than 10% of the stroke in order to enhance the effect.
It is obvious that the maximum conrod angles become asymmetric. What may be less obvious, is the increase in piston stroke for a given crankshaft stroke!
It is also remarkable that it takes more than 180 crank degrees from TDC to BDC, and less than 180° from BDC to TDC.

and it was much appreciated.

I should have been more specific re my latest question.
Were the Aprilia people asked to stop? and was it causing reliabilty issues?
As the info about whether the desaxle set up is hindering or helping potential reliability is quite contradictory.

Was it the increased vibes giving Aprilia problems or was there no problems? or no benefits was the reason testing was stopped.

 This stuff from the Bantam thread
adding one point to the RSA 125 point trevor noted, an aquantance of mine said they only dropped it because they were told to! and it was somthing to do with the increased friction at higher RPM apparently needed to much cost /time - and the potential that it cancells out the advantages at higher rpm because of the extra friction.
! But he who should be listened to, said there are possibilities for engines only running to 10,000 and with a low number of gears. !


As you can see, the design locates the piston to the side of the crank centerline, creating a straighter path for the connecting rod during the power stroke and reducing its sideways force on the piston as it slides up and down in the cylinder. This means less frictional losses and an easier life for the pistons and rods, which can be made lighter, thereby reducing reciprocating mass. That helps the Ninja make a record 197bhp, but bikes like the Honda CBR250R and even the Horex VR6 benefit too.

This stuff other sources

désaxé engines aim at giving the pistons an easier life.
During the power stroke, the cylinder pressure is forcing the piston down the bore, but the conrod is at an angle to it. This means the piston is being forced hard against the side of the bore, which every engine builder will know about as there’s always a lot more wear on one side of the bore and piston than the other. By shifting the cylinder to one side relative to the crank, the conrod’s angle with the piston is reduced during the downward power stroke, and the sidethrust is reduced with it.
This has two useful effects: one is a reduction in friction, improving the efficiency of the motor. The second is that because the peak forces on the pistons are smaller, they can be lighter, which in turn allows for lighter conrods and smaller bearings, also reducing internal friction.

Gigglebutton

31st January 2012, 17:29

Husaberg, Giggles does actually have a dentist drill, not sure if it came from the back of a German car though:lol:[/QUOTE]

I got it off Trademe from a bloke that made Grandfather clocks. You can still get the carbide burs for it from a croud that sell dentist bits over the shore. Made porting the RG50 so much easier.

2T Institute

31st January 2012, 20:43

My understanding is desaxation is a de facto long rod.
Funny the Mark Jordan pic as Mark sent me over a couple of those long series double cut burrs, very often used. Cheap diamond bits work OK and you can buy 1/8th end mills cheap off ebay.

F5 Dave

1st February 2012, 08:21

Sadly my father was a dentist (no German cars, we had a Monaro) but I never got cast off drills in time. Actually that isn't true, I had an old style handpiece as a toy when I was a nipper. Not sure where it went but a mate has one I borrow from time to time. Good for the 50 barrels.

dinamik2t

1st February 2012, 09:09

wobbly

1st February 2012, 10:14

Re the port floor positions - you are wrongly making the assumption that the cylinder deck is TDC.

dinamik2t

1st February 2012, 11:56

It crossed my mind at first, but to be honest I thought of a non-zero deck height to be more bizzare. I don't know why it shouldn't be:scratch:.
It is common with the C tfrs/boost ports, like here:

256425

Frits Overmars

1st February 2012, 23:00

mr Frits, I was thinking of the piston pin plugs. You think it would a succesful idea to use light, button-headed allen bolts on a inner threaded pin?
256419
Insert about 10mm (E/F) into each side, using thread locker and shape the head accordingly (which is easy and bolts are cheap to screw with). A small, swallow 6mm hex hole (K) would still cause short-circuiting?
256420
Also, would anyone know why port floors (or ceilings, if looked from below) sometimes extend further than the stroke height? Wouldn't that create turbulent flow on the spot?

What I mean can be seen in the rsa's (bleached) blue-prints here:
256421Light is the keyword, dinamik. I do not think it would be a successful idea to use any type of bolt there; in fact I know it would be a disaster. I did a lot of calculating and testing before eventually coming up with my 'plastic' (terribly expensive space-age stuff; it makes teflon look old-fashioned) end caps.
An RSA at maximum revs (14,500) generates quite some g's in its reciprocating parts: 48,700 m/s² at BDC and 77,160 m/s² at TDC. In case it escaped your mind: earth gravitation is 9.8 m/s²... So take a minute to calculate the forces that work on your light bolts, also take into consideration that these forces alternate at a rate of 242 times per second, and then take some aspirin and a stiff drink to calm your nerves.
By the way, you can do me a favour: drop the Mister. Just Frits will do fine; Mister makes me feel old (yes, I know, I am old).
Regarding your port floor question: not only is TCD below top deck like Wobbly pointed out, but there is another give-away in the drawing you used: Prelavorato means that the final dimensions have yet to be applied. The 53.1 mm bore dimension (for a 53.94 mm piston) might have been an indication, even if your Italian is not perfetto.
But you are right about the turbulent flow: the port floors should under no circumstances lie beneath BDC. Your picture of the two piston-fed C-grooves (I wouldn't call them ports) is hardly a good example; just consider the specific power that such kind of scavenging produces, compared to an RSA...

dinamik2t

2nd February 2012, 06:11

Howdy Frits! Wanna go grab a beer and talk about motor stuff? I'll call the girls too.. :shifty:
-hope no wives reading-

Anyway, thanks for the answers! :)
In your files by the way, there is a 'prelavorato' with 53.1 bore and a 'prelavorazione' with 53.8 and some hand-written corrections (?).

F5 Dave

2nd February 2012, 09:38

yes I've been thinking about pin plugs esp after my recent & knumbskulled experiment using spring steel as a shim in the end of a sleeved piston pin. The sleeves in the piston were fine, but the 0.5mm spring steel washer used as a (as it turns out unnecessary) shim lasted practice & one decent race start before disintegrating:blink:. There's obviously quite a harsh environment in there that one can forget about when handling the pieces & slo-mo head animation of the flow etc.

I'll pay some more attn before making up plugs.

TZ350

2nd February 2012, 11:06

yes I've been thinking about pin plugs ....

We have been experimenting with pin plugs too....

256494

Plug is a close fit in the pin and retained by the circlip.

256495

Last night on the dyno one side came loose, there were aluminium shavings all through the motor.

256496

The engine was making good power even after one side had come out and was taking a bit of a battering, the motor kept running, it was not until we stopped that it locked up and wouldn't re-start.

256493

Luckily there was no damage to the piston or cylinder.

I guess the plug was being batted back into the pin while the motor was running and it was able to drop into the transfer port when we stopped and jammed the piston when we tried to re-start it.

2T Institute

2nd February 2012, 12:30

Made many cheap and cheerful pin plugs from balsa and JB Weld, much to Frits' dismay:laugh: Worst that can happen is it falls out and gets burnt and disappears into the exhaust. A kart motor that got a slight bit of deto showed no residual traces of the plugs.

2T Institute

2nd February 2012, 12:35

TZ have you had a look at the kart shop for yamaha KT100 S gudgeons for comparision they are much thinner taper wall design than your gudgeon

dinamik2t

2nd February 2012, 12:57

I am troubled by the flat surface of the plug :wait:. Generally, how much area must there be in the spot, to determine whether the plug work as TFR/AUX.EX sealant or just a plain pin plug?

Institute, do you happen to have any photos? Balsa is the light wood material used in modeling planes, isn't it?

F5 Dave

2nd February 2012, 13:18

. . . Balsa is the light wood material used in modeling planes, isn't it?

Yeah & they used to strengthen it with a product called Dope. I have a bottle somewhere, I don't know what is in it, but I wouldn't get your hopes up.

Yes I wonder how close you need to get to avoid the Tfr/Aux as opposed to just blocking off the pin area to Tfr.

Yow Ling

2nd February 2012, 14:43

could you try these, a bit too Rangi maybe?
256516

bit of superglue then boosh all done

F5 Dave

2nd February 2012, 14:48

no no, I don't see any problem at all:innocent:

dinamik2t

2nd February 2012, 15:03

To avoid editing my old post, after Dave commented:

It should be more like the time-area.
One could make a small radius domed plug, which would still connect TFR-AUX when the top of the dome is before or after the horizontal wall divider.
Any dome radius would connect the two, at some point, for some time-area. So, the question is 'how long before a certain area does bleed pressure ?'.

256523

(...)

bucketracer

2nd February 2012, 22:32

256537

TeeZee's plug post was all about end caps for a short pin.

The piston pin was to short for the new piston's cir-clip spacing. Previously when the pin was able to shuttle back and forth it elongated the cir-clip grove, widening it to the point where a cir-clip very nearly came out.

This time Chambers made up some close fitting shouldered aluminum plugs to stop the pin slopping about. It appears that the repeated hammering by the pin was enough to drive one of the plugs far enough over the cir-clip for the end of the plug to be nibbled by the transfer port.

TeeZee and Chambers were running it up on the dyno and it wasn't until they stopped the motor that the plug fell out far enough to jam in the transfer and lock the motor up so that they couldn't turn it over again to re start. When the motor was stripped it was very hard to get the cylinder off and later the remains of the plug was found lying in the inlet port.

Both the old piston and cylinder survived without any damage and Chambers now has it all back together and running like a charm.

dmcca

3rd February 2012, 09:24

Was up late last night pulling my GasGas dirtbike down. To complicate matters, I can't help myself & while it was down being freshened up (& looing for an errant noise) I have to correct the squish clearance which is at 1.9mm.

Does the noise sound like piston slap or a rattle?... check the left side PV cylinder, the one behond the torque chamber cover, sometimes they need to be shimmed otherwise they move side to side and rattle.
Im currently working on an '11 model GasGas EC250 and Im amazed at how bad the workmanship is on that thing... so many problems its ridiculous... i should post up the portmap for a laugh, left aux EX port opens 1mm before right, main Ex is 2mm wider on one side than the other and shaped like a sideways egg, rather than an oval, port edges are razor sharp, cylinder is extremely badly pitted from poor casting with deep holes everywhere, intake tract is a joke... im really shocked at how bad it is. The last 2010 model i worked on was nothing like this, but there are too many issues for it to be a one off lemon that made it through the production line.

dmcca

3rd February 2012, 10:01

But you are right about the turbulent flow: the port floors should under no circumstances lie beneath BDC....

Frits, As a general principle i understand that its best not to have the port floors below BDC but in reality how much difference would a small step at bdc have given that the port is only fully open at BDC momentarily and for almost the entire port duration the flow has to negotiate the piston edge as it partly covers the port?

F5 Dave

3rd February 2012, 15:01

Thanks DMCA, yes I am aware of the freeplay of the PV actuator- but only last week. Mine had none. Although I forgot to melt the plastic out of the nylock nut & sheared the M4 thread so it had to meet mr welder to get it off.

Mine doesn't look that bad on first inspection, its an 07, but I haven't gone crazy, its a 300 dirtbike & has so much creamy power that's its perfect for a dirt muppet like me. Piston worn pretty bad & an A in a B bore which is a little worn. had 0.12mm clearance, that can't have helped:laugh:. New Woosner arrived for $210NZ so pretty happy with that.

Still a bit concerned with the rattle that popped up & lost power every so often. Can't find a reason. No signs of deto if it was the ign timing going potsy. Maybe the governor's balls were momentarily displaced (ooeer!:shit:) Was running fine at other times & pulled effortless wheelies even on rain mode. Hmm, might check all those CDI switches & connections.

On the topic though my '00 GasGas trials bike had the most shocking intake I've seen. The inlet manifold 'missed' the reedblock offset by a good 8mm!! I ground the side it hit flat wall & put in a acetal block in the overhang side.

TZ350

3rd February 2012, 17:22

I am getting a pipe kitset from Wobbly and a piston of ebay to rebore the 3 ex port cylinder but it wont make any more power, or power spread than the current single ex port and RS pipe setup unless I can increase the inlet port time area.

256549

I use Blairs rotary valve design program to basically rough out the dimensions needed then I enter the data into EngMod2T to see what the likely results are.

I am looking for 11 bar at 12,250 rpm

256550

But may have to settle for 10.5 bar because of the phyisical limitations on how big I can make the new rotary valve and inlet.

256551

Even so it sure is going to be bigger than the original GP125 hole.

256571

The larger rotary valve compaired to the original.

Gigglebutton

3rd February 2012, 20:37

[QUOTE=TZ350;1130249983]I am getting a pipe kitset from Wobbly and a piston of ebay to rebore the 3 ex port cylinder but it wont make any more power, or power spread than the current single ex port and RS pipe setup unless I can increase the inlet port time area.

Let me know when you get the pipe. I'll weild it up for you.

TZ350

3rd February 2012, 21:17

TZ had some pics way back with rlffler files bent to suit i guess the idea was from tuning for speed.I will post when i find them

256570

Found them...... more pics on the original post.

Tomas and Alexi heat and bend some rifler files to the shape they want.

Tomas said that if fine file marks are made across the direction of air flow then small air vortices develop and these act like ball bearings and the air mass slides easily over them.

It used to be all the rage to polish the ports but with a mirror polish in the port, the air boundry layer that clings to the port wall is quite thick and moves like treacle.

But a surface finish that promotes micro vortices that act like small ball bearings reduces the boundry layer too next to nothing and the air mass's resistance to flowing along the port is greatly reduced.

Tomas says a smooth polished surface that has been sand blasted is best and a fine file or sandpaper finish that cuts across the air flow is also very good but file or sand paper marks that go in the direction of air flow don't help much.

As a point of information, this is why golf balls are dimpled, rather than smooth - less drag, so they go further.

A quick check of my old fluids text (Massey, Mechanics of Fluids 6th Ed.) says the (thin) turbulent boundary layer promoted by the rough surface delays separation of the flow, reducing the drag caused by the gross separation (turbulence) of the flow across the surface.
Cheers,
FM

While we're on it (not easy for transfers mind); Small rotary carbide bits seem to work ok but are very good at leaving ripples, large flame type ones are much better but need a grunty Bosh(sp) or air powered with decent compressor to drive. Decent Stone bits take out irregularities leaving a flat surface with a honed appearance, mighty fine.

The good thing about stone and resin bits is that they can be re-shaped by running them up in a hand drill and working them against the side of a spining stone wheel in a bench grinder.

Some other posts on the same page have a few interesting ideas on port surface finish for best flow.......

TZ350

3rd February 2012, 21:20

Let me know when you get the pipe. I'll weild it up for you.

Great, thanks, will do.

I am building a complete new motor for the tripple exhaust port cylinder and Wobbly pipe, and I have a few new ideas about how to arrange the air cooling system so the head runs much cooler, and a better carb and bigger inlet port that I want to try out too.

The aim is to extend the current 30+hp and 4k power spread to 5k, who knows if it can be done but we will give it a go.

dinamik2t

4th February 2012, 04:21

Interesting potential. Good luck with the new engine - even though luck shouldn't have anything to do!:pinch:

The 4 bolts behind the R.valve what do they support? Any chance of rewelding and opening new holes in a trapezium pattern? It would give some extra area for the port, if needed.

TZ350

4th February 2012, 10:47

The 4 bolts behind the R.valve what do they support? Any chance of rewelding and opening new holes in a trapezium pattern? It would give some extra area for the port, if needed.

256604

The original inside plates diameter was to small for a bigger rotary valve so I fitted a bigger inner plate.

256603

The original counter sunk screws are used to fasten the bigger inside plate to the crank case, the outside ring of holes go right through to the crank case too and are for holding the outer cover on.

256614

Unfortunatly the inlet is not centered on the crankcase but a little forward of the centerline and the inlet tract is on an angle with the front part of the inlet tract angling towards the center of the crank case.

256605

The divider in the middle of the inlet port has a small kicker on it to help re direct the center part of the inlet stream.

256613

The rotary valve inlet as modelled in EngMod2T, pretty easy to see that the ideal model is much harder to realise in real life.

256612

EngMod2T model of the Big Blue EI 24-36 flat slide carb. The inlet tract tapers outward from the 24mm high velocity area just behind the slide to the 40.8mm diameter of the rotary valve port.

The angle that the walls taper out is important, too steep and the flow separates off the wall creating turbulence and reducing the overall mass flow through the inlet tract. From looking at venturi loss data I think 14 deg divergence is about the max for higher induction air velocitys and it can be steeper as the inlet tract area increases and the air velocity reduces.

The design aim is a big inlet port, short inlet tract and a divergent angle joining the two thats not so steep that it promotes flow separation.

Reducing the divergent angle by moving the inlet port closer to the carb wont do you any good because the inlet spends a lot of time only half open so you want the bigest inlet port practical.

Basic trigonometry shows that its just not possible to have an inlet port the size of a high hp side carb Aprilia, with a Bucket 24mm carb and an inlet tract short enough to work well at 13,000rpm without flow separation from the steeply diverging walls.

In the end it may be the maximum divergent angle possible of the inlet tract more than the maximum flow possible through a 24mm carb that limits the ultimate power obtainable from my 125.

TZ350

4th February 2012, 13:13

From:- http://www.engineeringtoolbox.com/orifice-nozzle-venturi-d_590.html

256619

The fluid slows down in the cone with smaller angle where most of the kinetic energy is converted back to pressure energy.

A gradual expansion of flow downstream of a nozzle eliminates flow separation, allowing recovery of most of the original pressure head. In the case where the main flow separates from the wall, a large percentage of the fluid energy is lost in the eddies caused by the separation.

A whole lot more on venturies http://www.flowsystemsinc.com/spe001.htm

256620

Looks a lot like my modified carbs where they have a flow straigtner at the front, then the 24mm venturi followed by a divergent pressure recovery area that forms the inlet tract.

256618

So it looks like, how steep you can make this angle without encountering flow separation is one of the major things that will determine how much power can be wrung out of a rotary valve 125cc 2-stroke limited to a 24mm carb.

It doesn’t necessarily have to be motorcycle related, if you have a few smarts pretty much anybody can find Goggle clues that help in tuning racing 2-strokes and getting the best out of any sort of performance engine.

Grumph

4th February 2012, 14:39

[QUOTE=TZ350;1130250437

So it looks like, how steep you can make this angle without encountering flow separation is one of the major things that will determine how much power can be wrung out of a rotary valve 2-stroke limited to a 24mm carb.

It doesn’t necessarily have to be motorcycle related, if you have a few smarts pretty much anybody can find Goggle clues that help in tuning racing 2-strokes and getting the best out of any sort of performance engine.[/QUOTE]

Eight degrees used to be the magic number...but I assume the people modelling flow dynamics may have moved this on a tad....

TZ350

4th February 2012, 15:15

Eight degrees used to be the magic number...

Was that eight or sixteen included angle?

In the literature there is quite a range and I have been finding it confusing trying to figure out if the quoted figure for the divergent section means diverging from the centre line or is the included angle of the cone if they don't also include the datum.

I expect the max angle possible is velocity dependent, it would be good to know what current thinking is regarding divergent cones and the typical velocities found in 2-stroke inlet tracts.

2T Institute

4th February 2012, 15:36

With IPO at 148 before will be hard to spread the power out(without a PV), a cheap and cheerful way of moving the disc timing is find how many deg 1 spline is, and juggle it around from there. A A100 we tested had very late closing with 120 IPO sacrificed some top end to pump up the mid when working with a 4 speed box. Has mid and a ton of over rev

Grumph

4th February 2012, 19:07

Was that eight or sixteen included angle?

In the literature there is quite a range and I have been finding it confusing trying to figure out if the quoted figure for the divergent section means diverging from the centre line or is the included angle of the cone if they don't also include the datum.

I expect the max angle possible is velocity dependent, it would be good to know what current thinking is regarding divergent cones and the typical velocities found in 2-stroke inlet tracts.

I always assumed from the context that it was divergence from the center line - ie 16deg included angle.....but I could be wrong....

rgvbaz

4th February 2012, 20:47

TeeZee,

I noticed that you are using two different flow widths for your inlet port. Exactly how I have been doing for ages :facepalm: until someone pointed out to me this bit in the instructions for Dat2T.

"Note: Even though the input and the following picture shows that the top and bottom flow widths can be different the software does not yet allow this and the users has to use the same value for the top and bottom flow widths."

I think you could use the average of the two flow widths to give you the same are of the trapazoid shape?

Dave

TZ350

4th February 2012, 23:14

"Note: Even though the input and the following picture shows that the top and bottom flow widths can be different the software does not yet allow this and the users has to use the same value for the top and bottom flow widths."

I think you could use the average of the two flow widths to give you the same are of the trapazoid shape?

Dave

I didnt know that, I thought I was doing the right thing, thanks for the heads up Dave.

Frits Overmars

5th February 2012, 00:27

....The design aim is a big inlet port, short inlet tract and a divergent angle joining the two thats not so steep that it promotes flow separation.....You can't have it both ways, but you can get close by compromising. Avoiding flow separation will lead to too long an inlet tract, and a very short tract will invoke a lot of pressure loss through flow separation. The best way is to accept some separation and the only way to try this out is with a running engine (unless you have access to a pulsating flow bench or a very powerful CFD program).

Eight degrees used to be the magic number...but I assume the people modelling flow dynamics may have moved this on a tad....Flow people may be getting ever better, but changing the laws of physics is still a bit beyond their power....

Was that eight or sixteen included angle? That was eight degrees included angle. But for your purpose you might want to start with 10° and then gradually try larger angles.
I expect the max angle possible is velocity dependentYou are on the right track. Approaching this scientifically, there is no fixed maximum angle beyond which flow separation will occur. The angle depends on the expansion behaviour of the gas. Expansion in the flow direction means increasing particle velocity; expansion perpendicular to this direction means the gas is filling the whole cross section of the diffuser. The ratio of these two expansion directions and velocities dictates the ideal shape of the diffuser, which will look like a horn.

TZ350

5th February 2012, 13:17

Thanks ....

TZ350

5th February 2012, 15:14

.
Av smokes em at Tokoroa.

Just had a race report.

Race 1 Av starts of the back of the grid, works her way through the field and takes the win.

Race 2 Av starts from row one and wins again.

Race 3 Av takes the win after lapping the entire field including the current F4 GP champion.

:first::first::first:

256696
Av and Chambers at Taupo

Av's bike was prepaired and tuned by Chambers, from Team ESE.

cotswold

5th February 2012, 16:36

.
Av smokes em at Tokoroa.

Just had a race report.

Race 1 Av starts of the back of the grid, works her way through the field and takes the win.

Race 2 Av starts from row one and wins again.

Race 3 Av takes the win after lapping the entire field including the current GP champion.

:first::first::first:

256696
Av and Chambers at Taupo

Av's bike was prepaired and tuned by Chambers, from Team ESE.

Nice,,
Go the 2 strokes!!

F5 Dave

6th February 2012, 03:27

That's fantastic news, but mainly 'cause it means she made it there & thus took my tyres:niceone:.

Well I've been having a bear of a time on the dyno. My MB just won't pull consistent runs. Now I know the cases leak due to incompetent welding many years ago despite gluing them together & new crank seals (I spent a couple of hours on the mill today on new cases).

But the behavior on the dyno is queer. it is making peak power at 10,000 & falling off a couple of hp or lots & ign trace goes. When it wasn't running as well peak power was 12,200. That is what it is tuned for & hits it.

I changed the ign as the NF4 RS igns are often dodgy, but no better, in fact worse. But the odd thing is it runs up better often if I start the run from 4000rpm. And in an 'all gear' run it occasionally pulls through & makes power & that gear curve is much wider than the rest. It does make a bit of a noise on the run & seems to pass through the gear a bit quick.

But a slipping clutch doesn't behave like that, I've had a H100 (same as MB clutch) slip & they tend to slip a bit when cold & lock up. Or just stay slipping, but from low revs. Now I have a Green modified pack which handles his 30hp with a touch of preload on the std springs.

I did have an issue when I first ran the bike on a long high gear cct as it slipped and I had to be careful how I applied the power, then as it got warm it seemed better. I made some spacers & preloaded it so it coilbinds just as the lever touches the grip.

As I lay awake (you may notice the timestamp is 4:30am) I am pondering the leaking cases. . .but; what I think I have created is a consistent action clutch that slips after a certain level of power - that is made after 10,000. Time for new plates & retry. Or stiffer springs.

Or try & think of a new hypothesis as why a 4,000 rpm run or an all gear run makes it carburete better at 12,000. Not that the slow rev start should have much effect on the clutch, but who knows?

bucketracer

6th February 2012, 06:38

... say two bucket racers, a low power/high torque bucket will only beat out high power/low torque bucket if the race is short (initial acceleration is higher for high torque) ...

Could be the reason that FXR150's are so good from the apex to the first few bike lengths out, often being able to get their wheel in front of a stroker.

... Now, of course, the ultimate goal is to have a high speed high torque bucket (i.e. a torque curve that is flat, and at flat at the maximum torque). But that is a higher power bucket anyway, because of the combination of high speed and torque.

Cheers,
FM

256755

A flat torque curve typical of the Team ESE bikes.

TZ350

6th February 2012, 08:50

Changing the inlet tract angles by having a bigger rotary valve disk and smaller port window.

256757

I feared that the 11.4-15.2-16.7 deg were too steep and would promote flow separation and reduced bulk flow.

256758

So it looks like, by using a larger rotary valve disk I am able to have a smaller port window and shallower divergent angles 10-10.7-10.9 but the same STA as the bigger port because the smaller one will be fully open for longer at the larger radius.

The EngMod2T simulator is great for figuring this stuff out.

Gigglebutton

6th February 2012, 08:59

Gigglebutton

6th February 2012, 09:01

wobbly

6th February 2012, 09:39

Try putting the venturi directly behind the slide like Lectron did - this will shorten up the divergent length with much slower angles out to the RV port area.
Easy to test the flow capability of the varying venturi positions and divergent angles on a flow bench before hitting a dyno.

husaberg

6th February 2012, 14:11

No doubt someone will "pipe up" with a couple of cliche's about the bike.
but Kevin Cameron says what i would describe as some interesting things in this article regarding the development path of this and other TZ Yamaha's.

Could someone more learned than myself ever confirm or more likely deny a few bits in here as it seems to go against some prevailing wisdom in regards to a few technical pieces.

I could be bothered highlight the relevant piece's as the highlighter always moves.

What kevin Cameron mention's he has also mentioned Mculloch engines doing it as well in regards to the Reeds.
I personally found the bits about the squish clearance and band width a bit confusing. But i might be more thick than i originally thought.

The reasoning for the flat slides was interesting as I had not seen it described like that before.

Also forgot incredibly ugly intakes what "up" with that.

wobbly

6th February 2012, 15:37

Nothing too much off the mark - except the old bullshit tale about the pipe pulling the reeds open.
How it goes is that the diffuser sucks like hell on the cylinder around BDC - this pulls gas out the transfers, they pull on the case, and this opens the reeds, allowing more mixture in.
Crap.
Here is a sim trace of a RGV100 at 13,000 making 40 odd crank Hp.
BDC is exactly between TPO and TPC, the reed lift down the bottom isnt showing the reeds much open till TPC - well after BDC, so the pipe action isnt affecting the reed lift at all, apart from
a delayed reaction due to petal stiffness and column inertia in the intake.

Re smaller case volume, I have measured one of those engines and its case com is exactly 1.3 on one side and 1.29 on the other with around 540cc from memory..
This is alot smaller than an Aprilia at 640cc.
But its case vol is relatively large in comparison to 2T technology at the time.
In a 125 project I have just finished, with a case reed, 1.3 gave the best result.
Going down to around 1.24 of the RSA spec lost around 2Hp with the reeds, no matter what I did with intake length and petal stiffness, pipe geometry or carb size.

Re the squish shape and chamber geometry.Yamaha always had odd ideas about what was correct, or best, and never really led the way at all until unleaded became mandatory.
Then the YZR was fast once Kennys boys got them on Asklands dyno.
And they kicked everyone's arses , even in 250 when they fitted the spool valved cylinders off the 500

husaberg

6th February 2012, 18:40

Re the squish shape and chamber geometry.Yamaha always had odd ideas about what was correct, or best, and never really led the way at all until unleaded became mandatory.
Then the YZR was fast once Kennys boys got them on Asklands dyno.
And they kicked everyone's arses , even in 250 when they fitted the spool valved cylinders off the 500
I guess you are meaning except for the 500 class cause the fuel came in mandatory in 98 i believe and Yams results aren't so special after that.
from what i understand the lower lead fuels introduced in 94 ish benefited Honda.

Just checked the 250cc and the 125cc results as well. There's bugger al Yamaha 2 stroke world champions after 1998 (IE one on a twostroke by the look of it). Why were they kickings arses softly?

wobbly

6th February 2012, 19:07

Yamahas basic technology took big strides forward after 98, the 500s were very fast but Doohan was faster.
Prior to that the engine tech was crap and Askland changed everything in sight to make Wayne a bike fast enough to win.
With the factory finally getting off the high horse and admitting Honda was right all along with 54 square, and then they added back the superior spool valve
that worked so well in the old RZ - then riders like Laconi, Abe , McCoy,Checa and Biaggi won races without having teams that changed everything inside to make them go.
Even Crafar had a chance to take the title in 1998, with fastest laps, fastest top speeds etc, Doohan was a genius of the first order but Simon had a bike that was capable of winning every time out.
All this was put together in 2000 for the 250 that was utter shit prior, in relation to the Aprilia or Honda.
Nakano and Jacque fought it out down to the last lap at PI.
Then they stopped development again,odd buggers to say the least.

husaberg

6th February 2012, 19:28

and then they added back the superior spool valve
that worked so well in the old RZ -
Then they stopped development again,odd buggers to say the least.

That's something i haven't seen on this thread yet. That is a comparison of the different power valves with the pro's and cons of each style.

Honda RC "Revolution Control" Valve

Good points

Simple, Easy to modify, Rugged, unlikely to snap and be swallowed by the engine, Easy to modify for a smaller bore engine. Electrically controlled servo motor so potentially reprogrammable in operation. Able to be shaped to the contour of the bore.

Bad Points
Has to be adjusted.
Has the potential to gum up.
Because it travels in an arc it may have a limited range of effective operation.

2T Institute

7th February 2012, 00:10

All this was put together in 2000 for the 250 that was utter shit prior, in relation to the Aprilia or Honda.
Nakano and Jacque fought it out down to the last lap at PI.
Then they stopped development again,odd buggers to say the least.

Time for my big note myself me at the GP spiel..........:laugh:

I asked Herve Poncheral(see name dropping already) about the 2000 season with the 250's, he said in the years prior they did everything themselves and 1999 the factory started to do everything for them. Herve also said that Nakano took the defeat 'like a gentleman' and if Jacque had been on the receiving end there would have been "big fireworks" in the pit box afterwards.

Frits Overmars

7th February 2012, 00:27

... say two bucket racers, a low power/high torque bucket will only beat out high power/low torque bucket if the race is short (initial acceleration is higher for high torque) ...I missed that original quote by Fooman (maybe it was in a different topic?), otherwise I would have wrung his neck corrected him.
Torque is something you distill from power with the help of a gearbox. You can have bulldozer torque, but if you have no revs, you cannot use a transmission ratio that multiplies this torque before it is put on the tarmac. On the other hand, if you have featherweight torque and a lot of revs, you can use a total transmission ratio that mutiplies that feeble torque tenfold before it gets to the rear tire.

Thats one very homely looking Brolly Dolly behind Av You guys' creativity with the language of Shakespeare never ceases to amaze me.

Try putting the venturi directly behind the slide like Lectron did - this will shorten up the divergent length with much slower angles out to the RV port area. Easy to test the flow capability of the varying venturi positions and divergent angles on a flow bench before hitting a dyno.I agree re the place of the venturi. But that flow bench test would give you zero information about the intertia of the inlet gas column, Wob. A normal flow bench operates with steady flow, but steady flow is something you will not find anywhere in an engine.

Re the articles by Kevin Cameron which, by and large, are excellent reading:
Cameron mentions large area reeds needing low stiffness which allows them to open almost as soon as the piston rises. But the opening of the reeds has nothing to do with piston motion; the reeds are opened by a pressure differential and that can occur even while the piston is on its way down (imagine pipe suction at really low revs).

Guillotine exhaust power valves in the Yamaha 250 cc V-twin caused a peculiar problem: oil collected in the sheath for the valve of the down-sloping cylinder, acting as a hydraulic block on the valve. We drilled a small leak hole to get rid of the problem.

In a piston-portdesign.. it is desirable to make the crankcase big so that the exhaust pipe's suction phase has plenty to draw upon for effective cylinder scavengingTrue, true.
In a large-area reed design however the reed can reopen shortly after BDC....and can then supply as much extra mixture as the exhaust pipe is capable of hauling up through the cylinder. Such an engine no longer needs a large crankcase.Wrong, wrong. The 'plug' of mixture in the intake duct strongly resists being accelerated towards the crankcase; the crankcase pressure has dropped quite a bit (slowing down the transfer flow in the process) before the intake flow starts attributing something useful to the crankcase contents. And the same goes for rotary inlet engines; they too need large crankcase volumes to make real power.
Wob, the pipe does suck like hell on the cylinder and hence on the crankcase. It just doesn't show at the reeds until a lot later because of, like you say, petal stiffness and column inertia.
By the way; the Aprilia RSW's crankcase volume at TDC (that means including the transfer ducts) is about 650 cc; the RSA's volume is about 675 cc. But they open their rotary inlets when they want to; they're not at the mercy of any stubborn reeds.

Several riders of the Cagiva 500-4 works racers experienced a painful demonstration of this stubbornness:
When closing the throttle for a corner (a 500-4 will need that from time to time) engine power dropped. But when they reopened at the corner exit.... nothing happened. The reeds had to be opened by the suction of the exhaust pipe, but when there is no combustion, there is no suction. So the riders opened up a little more. And a little more. And more.... And then, at some point, there was once more sufficient combustible mixture in the cylinder to be ignited. The pipe suction returned from its coffee break and the whole two-stroke resonance cycle was reinstated - with the four carbs wide open. That hurt....
The problem was solved by inserting thin strips under the reeds, so they never really closed completely. It messed up the carburation and cost over 10 HP, but it improved both the lap times and the mileage you could put on a rider.
Later, because of those carburation problems, Cagiva was one of the first to switch from carbs to injection.

andrew a

7th February 2012, 07:31

Well done Av you rode well. Very well indeed. Yes I got laped. I did a bit of off track grass work! Anyway there was no way I could get anywhere near her pace. Well done to Av and team ESE.
.
Av smokes em at Tokoroa.

Just had a race report.

Race 1 Av starts of the back of the grid, works her way through the field and takes the win.

Race 2 Av starts from row one and wins again.

Race 3 Av takes the win after lapping the entire field including the current F4 GP champion.

:first::first::first:

256696
Av and Chambers at Taupo

Av's bike was prepaired and tuned by Chambers, from Team ESE.

wobbly

7th February 2012, 07:33

As always Frits your keen mind keeps us on the straight and narrow path.
I fully realise that the pipe sucks like hell at BDC,the sim pressure ratio trace shows that dramatically when the diffuser shape is correctly designed.
Pipe depression causes a big pressure ratio across the transfer duct/cylinder boundary, and it is this effect that causes the bulk flow around BDC.
But what I was alluding to, was that to then go on to say that the pipe opens the reeds, around BDC, just isnt true.

Re the carb venturi - having the smallest point within the carb up at the slide will reduce the divergent angle up to the RV area.
All I was suggesting was that the flow bench would establish if that "slow" divergent angle made any tangible difference to the ( steady state ) flow capability.
It may "look" right but I know enough about flow tests to know that what looks good sometimes ( often) isnt.
If bad turbulence created a flow loss capability, the bench would show this immediately, on the dyno it could be several things causing less power to be produced.

What i was saying re Yamaha and the bikes they built around 1998, was that prior, Rainey kicked arse due to his talent and the work put in by the team to fix the problems.
About that time they then changed alot of the basic elements, ran a CNC anemometric flow tester etc, and suddenly a heap of riders were on machines that could win, even the privateer WCM guys had a fighting chance.

Yamahas spool valve would seem to be the best system for a single or 3 port setup.
It is always close to the piston, no matter what leading edge height it has, and can also control the secondarys at the same time.
Aprilias multi section blade is a good patch up of a flawed design, but it doesnt control the secondarys - maybe not such a big issue in a full noise application.

For the T port, Hondas dropping gate works very well.Its design in the RS250 cylinder is much better than the ones Husaberg showed in that the pivot point is alot further
away from the piston.Thus the arc away from the piston is alot slower.
Suzukis twin multi section tubular valves are complex but clever as well, and like Hondas gate they conform well to the port roof when open.

F5 Dave

7th February 2012, 10:38

dinamik2t

7th February 2012, 11:04

Wrong, wrong. The 'plug' of mixture in the intake duct strongly resists being accelerated towards the crankcase; the crankcase pressure has dropped quite a bit (slowing down the transfer flow in the process) before the intake flow starts attributing something useful to the crankcase contents. And the same goes for rotary inlet engines; they too need large crankcase volumes to make real power.
Wob, the pipe does suck like hell on the cylinder and hence on the crankcase. It just doesn't show at the reeds until a lot later because of, like you say, petal stiffness and column inertia.

Here is a sim trace of a RGV100 at 13,000 making 40 odd crank Hp.
BDC is exactly between TPO and TPC, the reed lift down the bottom isnt showing the reeds much open till TPC - well after BDC, so the pipe action isnt affecting the reed lift at all, apart from
a delayed reaction due to petal stiffness and column inertia in the intake.
Re smaller case volume, I have measured one of those engines and its case com is exactly 1.3 on one side and 1.29 on the other with around 540cc from memory..
This is alot smaller than an Aprilia at 640cc.
But its case vol is relatively large in comparison to 2T technology at the time.
In a 125 project I have just finished, with a case reed, 1.3 gave the best result.
Going down to around 1.24 of the RSA spec lost around 2Hp with the reeds, no matter what I did with intake length and petal stiffness, pipe geometry or carb size.

Frits, Wob, could you give us an insight, into how one can use the big volume of the crankcase effectively, in a high performance design? Would there be any rules connecting crank volume with ducts volume or pipe volume?

I simulated two different ratios in EngMod, and the higher comp/smaller volume was up by 1+hp. Both with the same tfr duct volumes (~78cc).
I did a hasty overlay of the pressure waves of the intake and exhaust:

256943

256944

The higher comp case caused the reeds to open less. Tfr pressure was higher from Ex open until just-before Tfr closed. Crankcase pressure was higher too.
On the exhaust part, difference was mainly betweet Tfr open and close, both for cylinder and exhaust pressure - higher comp produced the higher pressure.
Also, delivery ratio was much bigger in the high-comp, while TubMax was slighly less.

edit: I don't know whether I am missing something here, but EngMod kind of shows what you told us about 'pipe sucking from tfr ducts and that vol being important'.
I run the same as above, with 1.45 crank comp ratio, to see a number of 30.4kw. Then, with longer TFR passages (new vol about 100cc), with 1.3 CCR it showed 33.2kw, while with 1.45 it rised to 33.6kw.
I think it favorises a little the high primary comp ratios.

speedpro

7th February 2012, 13:05

A layman's (mine) view of the effect case volume has is that a larger volume has a smaller drop in pressure given any particular volume transfer up the transfer ducts. As it is the pressure differential between the cylinder and the case that causes the transfer flow having the largest possible pressure differential for as long as possible will result in the maximum volume flow possible. As with anything in pesky 2-strokes there is a trade-off and therefore an optimum value of crankcase volume given any particular application.

You could go for smaller volume, higher compression, crankcases but that would only benefit initial transfer flow before the crankcase pressure dropped. However there may be some advantage in this setup with smaller transfer ducts if the energy in the initially rapidly moving mass in the transfer ducts could be used.

Maybe.

TZ350

7th February 2012, 15:05

Try putting the venturi directly behind the slide like Lectron did - this will shorten up the divergent length with much slower angles out to the RV port area.

256968

Easy to test the flow capability of the varying venturi positions and divergent angles on a flow bench before hitting a dyno.

256967

This is what my ventori tube looks like, flow is from left to right, two ramps, leading ramp is 34 deg included and trailing ramp is 14 deg included angle.

Could the flow be improved by making the leading edge ramp into an aero foil shape like the leading edge of an aeroplane wing as in your picture.

It would certainly shorten up the tube and get the venturi point closer in behind the slide.

husaberg

7th February 2012, 16:39

Missing a page there?

Last one wouldn't fit but was not not real interesting but here it is.
If you are meaning the carb explanation it is on the bottom paragraph of the first page in the original post attached on the left column.Well bugger it if that is what you are after this highlighted bit

wobbly

7th February 2012, 16:56

Here is my first thought.
The carb inlet length is still too long though, so you would have to try steeper exit divergence to shorten this up.

F5 Dave

7th February 2012, 16:56

what does page 58 (d) go on to?

page d: Crank balance holes have been filled. . . .
page e: . .. . 2mm higher in the new pistons. . .

erm?

husaberg

7th February 2012, 17:10

what does page 58 (d) go on to?

page d: Crank balance holes have been filled. . . .
page e: . .. . 2mm higher in the new pistons. . .

erm?
Oh sorry all the pages are there with the exception of the last added a page back (that was chassis related) This is how it is written sorry.
I guessed he was saying the balance holes were filled flush. and the piston gudgeon was moved 2mm higher both to lower crankcase comp? But not sure.

You could a write latter to the editor suggesting that there may be a piece missing in their August 1988 issue You could get a free subscription.<_<

Frits Overmars

7th February 2012, 21:34

Frits, Wob, could you give us an insight, into how one can use the big volume of the crankcase effectively, in a high performance design? Would there be any rules connecting crank volume with ducts volume or pipe volume? I simulated two different ratios in EngMod, and the higher comp/smaller volume was up by 1+hp. Both with the same tfr duct volumes (~78cc). I did a hasty overlay of the pressure waves of the intake and exhaust:
The higher comp case caused the reeds to open less. Tfr pressure was higher from Ex open until just-before Tfr closed. Crankcase pressure was higher too. On the exhaust part, difference was mainly betweet Tfr open and close, both for cylinder and exhaust pressure - higher comp produced the higher pressure. Also, delivery ratio was much bigger in the high-comp, while TubMax was slighly less.
edit: I don't know whether I am missing something here, but EngMod kind of shows what you told us about 'pipe sucking from tfr ducts and that vol being important'. I run the same as above, with 1.45 crank comp ratio, to see a number of 30.4kw. Then, with longer TFR passages (new vol about 100cc), with 1.3 CCR it showed 33.2kw, while with 1.45 it rised to 33.6kw. I think it favorises a little the high primary comp ratios.In order to take full benefit of a large crankcase volume you need free-flowing transfer ducts. That means: large cross sections, short gas column lengths and large time.areas. Of course I don't know which dimensions you entered into the sim, but am I wrong in thinking they may have been more restrictive than the Aprilia values?

A layman's (mine) view of the effect case volume has is that a larger volume has a smaller drop in pressure given any particular volume transfer up the transfer ducts. As it is the pressure differential between the cylinder and the case that causes the transfer flow having the largest possible pressure differential for as long as possible will result in the maximum volume flow possible. As with anything in pesky 2-strokes there is a trade-off and therefore an optimum value of crankcase volume given any particular application. You could go for smaller volume, higher compression, crankcases but that would only benefit initial transfer flow before the crankcase pressure dropped. However there may be some advantage in this setup with smaller transfer ducts if the energy in the initially rapidly moving mass in the transfer ducts could be used.Maybe.You're not doing too bad for a layman. Skinny exhaust pipes, high crankcase compression and narrow transfers with timings over 140° were common in the sixties.
These factors were interdependent: the skinny pipes hardly produced any decent exhaust suction, so you needed the pumping action of the small crankcase volume. And because of the narrow transfer windows you needed long timings to get anywhere near workable time.areas.
Your final remark about using the energy in the initially rapidly moving mass in smaller transfer ducts needs some comment. The energy of a moving gas or mixture column depends on its mass and its velocity. In ducts with large cross sections the flow velocity does not rise too high because the crankcase pressure can drop fairly rapidly. In short, narrow ducts the velocity will rise allright, but the mass in the ducts will be small. And in long, narrow ducts the long plug of gas will resist acceleration and will only slowly come up to speed. Because long columns are such slow starters, the kinetic energy at the latter stage of transfer will only make up for what went missing at the initial stage.

256967

This is what my ventori tube looks like, flow is from left to right, two ramps, leading ramp is 34 deg included and trailing ramp is 14 deg included angle. Could the flow be improved by making the leading edge ramp into an aero foil shape like the leading edge of an aeroplane wing as in your picture. It would certainly shorten up the tube and get the venturi point closer in behind the slide.Yes, make it into a bellmouth. That will get you both a shorter unit and a better inflow. You might also consider putting the restriction in the bellmouth if your rules allow it. That would mean you can have a considerably longer trailing ramp (the widening can start right after the bellmouth, i.e. under the throttle slide). It also means that only the air, not the fuel, has to pass through the restriction. That way the total mass that has to be accelerated through the restriction, will be about 8 % less.

teriks

8th February 2012, 09:32

I'm quite sure it's already been mentioned in this thread, but it might be time to re-visit Blairs piece on bell mouth's in RET.
Unfortunately www.profblairandassociates.com seems to be down, and the pdf is over the file size limit for attachments here.
I found a copy on scribd though: http://www.scribd.com/doc/57695028/RET-Bellmouth-Sept

dinamik2t

8th February 2012, 10:31

In order to take full benefit of a large crankcase volume you need free-flowing transfer ducts. That means: large cross sections, short gas column lengths and large time.areas. Of course I don't know which dimensions you entered into the sim, but am I wrong in thinking they may have been more restrictive than the Aprilia values?

I used 1.2 ratio for tfr passages and about 70mm for the curved length. Total window area ~1050mm2.
There wasn't that much difference though, because I didn't notice I used "passage volume included" in some tests and "passage vol excluded" in others. In conclusion, from 1.3 to 1.4 crank comp, difference was about +0.3hp and that might be even less if inlet length was fine-tuned too.
So, my mistake.

By the way, we use RSA engine specs as a reference, for pretty much everything here.:eek:

I came across a photo that reminded me of the rsa cylinder:
Says it's the cylinder of a 250 twin RVed, by Harald Bartol (the one on KTM gp) in 1981
257009

SS90

8th February 2012, 12:06

Money can't buy this.

bucketracer

8th February 2012, 14:04

I have been doing a lot of the Team ESE’s dyno work lately and gaining a lot of experience while getting paid to make engine parts after school for the Team as well as making an income building a special engine or two for customers, now some of our engines are leading the pack.

257073

Having done a lot of the work helping TeeZee develop his 31hp Bucket engine, the Team recons that I have a few clues, and a bit of talent and can now call myself a real industry insider with a bit of worthwhile tuning knowledge and experience........... :niceone:

kel

8th February 2012, 15:09

[QUOTE=bucketracer;1130253449] ... getting paid to make engine parts after school for the Team as well as making an income building a special engine or two for customers, QUOTE]

I hope you're charging accordingly (dont accept that youth rate/work experience crap), considering last weekends annihilation of what was the GP field (less southerners) you can probably name your price.

wobbly

8th February 2012, 18:01

rgvbaz

8th February 2012, 19:46

[QUOTE=Frits Overmars;1130252231]

You guys' creativity with the language of Shakespeare never ceases to amaze me.

QUOTE]

Frits,

If you like creative use of the english language check out the profanisaurus here http://www.milkinfirst.com/dictionary/profanisaurus.htm

which comes from Viz here http://www.viz.co.uk/profanisaurus.html

Dont show your mother! it is a bit close to the knuckle

Dave

husaberg

8th February 2012, 21:21

I was at the old mans for tea tonight.
Whist the ladies were gasbagging.
I took a few pics of some cylinders out of the shed.
Bear in mind this is an interestingly modded 1960's Greeves cylinder,
Maybe at the time it was a common mod but i guess it was aimed more for relibility than for performance.Maybe grump as seen the inlet mod before i don't believe it could be factory
I was quite taken with the curvaceousness of the transfers the pictures are poor quality sorry forgot my camera and used my cell.

No pics but it also has the squarest top hat combustion chamber i have ever seen.

I found a AMC cylinder too which looks like the modded Villiers that i will post below.It is amazingly heavy compared to a comparable Villiers.
No pics as it has a stuck piston at the moment.

husaberg

8th February 2012, 21:28

This is a Villiers engine that has had the transfers modded in a way which resembles a Piatti AMC 2 stroke.
As it is not currently attached to a racing engine i guess it is/was not the most successful mod but it is different not the length of the piston skirt on the 59x72mm 197cc engine. Note the brass inserts on the piston. Again sorry re the quality of the pics.

Oh TZ i found a swag of 1960's kart mags i will email you the pics of the stuff you want.<_<

koba

8th February 2012, 21:30

Dont show your mother! it is a bit close to the knuckle

Some of that IS Shakespeare

beast with two backs n. A strange grunting animal with 2 heads and 4 legs, commonly found in bus shelters after midnight.

Frits Overmars

8th February 2012, 22:46

....I came across a photo that reminded me of the rsa cylinder: Says it's the cylinder of a 250 twin RVed, by Harald Bartol (the one on KTM gp) in 1981
257009Here is the Bartol engine to go with that cylinder:

Frits Overmars

8th February 2012, 22:57

As we were talking about Yamaha and their lack of results here is an interesting story. Harold did the CNC anemometric flow testing on the BSL cylinder for me that I had lithographed in plastic. He showed me the dyno curves of his cylinder Vs Yamahas on the 125 when he was running their team with the Japanese rider Ui. Yamaha wouldn't let him use his 50.2 Hp set-up on the bike - even though their cylinder only managed 44.Here is the preceding story, Wob, as told to me by my recently-passed friend Cees van Dongen. Cees was working on his son's Yahama TZ125 which was no match for the Honda RS125, power-wise. Cees changed the stroke from 50.7 to 54.5 mm and put a Honda cylinder on the Yamaha engine. Problem solved.
Bartol, facing the same problem while he was working for the Kurz Yamaha team, noted the dutch solution. Bartol also had a good connection with the factory and offered to develop a better cylinder for the TZ125. The Bartol cylinder turned out to be an exact copy of a Honda cylinder. Yamaha was not pleased...

husaberg

8th February 2012, 23:02

grabbed what i thought was a Piatti AMC engine cylinder.It turns out it was not what i thought it was.

It has a very British Hepolite piston +60 thou it has massive transfer cut always so very un-villiers.

It also has unusual transfer bulges outside of cylinder so again un-Villiers but no transfer slots and a flat top piston.
It may be the mark 2 version mentioned in the Villiers article i posted? Also judging by the bore it must be a 250.
it is unbelievably heavy compared to the 8e/9e.

Most unusually it has a heart shaped inlet port. poor quality pics sorry as now, i can't find my camera.:brick:
Can anyone make a call on what it is?

I guess you may have to be over 60 to answer the question sorry

cotswold

9th February 2012, 01:59

wobbly

9th February 2012, 07:31

The other thing to add to that Frits is a lesson that was well taken from Harold by me.
He made a reed setup that had large stuffers down each side of the block.
The logic was that Yamaha's reed was way too big,loosing a heap of velocity as the flow exited the manifold.
The reed block he used - off a Honda.

TZ350

9th February 2012, 16:01

257152

By a bit of clever machining Bucket managed to lose 15mm from the inlet tract length (it was 145mm). We will see how that goes tomorrow night.

257151257150

You might also consider putting the restriction in the bellmouth if your rules allow it. That would mean you can have a considerably longer trailing ramp (the widening can start right after the bellmouth, i.e. under the throttle slide). It also means that only the air, not the fuel, has to pass through the restriction. That way the total mass that has to be accelerated through the restriction, will be about 8 % less.

257146257147257148

Its a little grey, some people feel a carb should always be measured at the same point that the original manufacturer measured it, but yes the rules seem to allow carb mods and we have tried your idea before and it worked OK.

The interesting thing is, that the signal strength was much greater and we had to reduce the main jet, we went from 140 down to 100 which is the smallest we could get, made 31rwhp with the 100mj, maybe there is more if we could get smaller jets.

When I settle on a carb configuration Lectron are open to looking at providing them as 24mm specials if they like the design, then the carbs would be available on special order to anyone who wants one so they will be completely within the rules or a punter could save quite a few $$$ and modify something for themselves.

dinamik2t

9th February 2012, 16:34

TZ, you could buy a couple from ebay: http://www.ebay.com/sch/?_nkw=keihin%20main%20jet&_clu=2&_dmpt=Motorcycles_Parts_Accessories&_fcid=80&_localstpos=&_stpos=&gbr=1

husaberg

9th February 2012, 16:48

Here is the preceding story, Wob, as told to me by my recently-passed friend Cees van Dongen. Cees was working on his son's Yahama TZ125 which was no match for the Honda RS125, power-wise. Cees changed the stroke from 50.7 to 54.5 mm and put a Honda cylinder on the Yamaha engine. Problem solved.
Bartol, facing the same problem while he was working for the Kurz Yamaha team, noted the dutch solution. Bartol also had a good connection with the factory and offered to develop a better cylinder for the TZ125. The Bartol cylinder turned out to be an exact copy of a Honda cylinder. Yamaha was not pleased...

The other thing to add to that Frits is a lesson that was well taken from Harold by me.
He made a reed setup that had large stuffers down each side of the block.
The logic was that Yamaha's reed was way too big,loosing a heap of velocity as the flow exited the manifold.
The reed block he used - off a Honda.

So the real secret to getting a Yamaha to run hard.
Is to put in a complete Honda engine then:msn-wink:

Kickaha

9th February 2012, 20:03

So the real secret to getting a Yamaha to run hard.
Is to put in a complete Honda engine then:msn-wink:

There used to be a kit in the states to change the nineties TZ125 to the same bore x stroke as the RS125

2T Institute

9th February 2012, 23:20

The 'kit' came out after the 54 X 54.5 TZ came out :msn-wink:. The 56mm TZ is a right bitch to tune almost any usual tuning trick results in a loss of HP.

Frits Overmars

10th February 2012, 00:30

Its a little grey, some people feel a carb should always be measured at the same point that the original manufacturer measured it, but yes the rules seem to allow carb mods and we have tried your idea before and it worked OK.
'Some people' can feel all they want, as long as they stay away from me and the missus.
Reading a rulebook is every bit as important as preparing an engine. I practiced reading between the lines all my life, before I became a technical adviser to the royal dutch motorcycle union KNMV and (much more fun) to the dutch moped racing union SOBW, so I know how to read a rulebook. Before I joined, the moped rules stated for example that the carburetter should not be larger than 20 mm. But nowhere in the rulebook did it say that you could have only one such carburetter...

Frits Overmars

10th February 2012, 00:33

Its a little grey, some people feel a carb should always be measured at the same point that the original manufacturer measured it, but yes the rules seem to allow carb mods and we have tried your idea before and it worked OK.
'Some people' can feel all they want, as long as they stay away from me and the missus.
Reading a rulebook is every bit as important as preparing an engine. I practiced reading between the lines all my life, before I became a technical advisor to the royal dutch motorcycle union KNMV and (much more fun) to the dutch moped racing union SOBW, so I know how to read a rulebook. Before I joined, the moped rules stated for example that the carburetter should not be larger than 20 mm. But nowhere in the rulebook did it say that you could have only one such carburetter...:msn-wink:

speedpro

10th February 2012, 06:54

Which is the exact reason for the wording of our rules being "carburation equivalent to a single 24mm carb"

F5 Dave

10th February 2012, 08:19

. . the moped rules stated for example that the carburetter should not be larger than 20 mm. ...thats a pretty small carburettor, be hard to get a bore size of more than 8mm:confused:.

speedpro

10th February 2012, 11:02

thats a pretty small carburettor, be hard to get a bore size of more than 8mm:confused:.

This is why nobody likes you Dave.

F5 Dave

10th February 2012, 13:17

That's not what you said last night.:love:

TZ350

10th February 2012, 15:37

257204257205257206

Working on the EI carb with the 24mm venturi behind the slide, its a bit of a trick getting the mixture right. Its easy to wind the needle up and down and have it either rich on top lean below or the other way around. But not having a good selection of needles, I am having to stone the flats on the two needles I have, to try and get a profile that fuels correctly.

257208257203257207

A comparison of the OKO with the 24mm restriction in the bellmouth like Frits suggested (Red Line) and the EI carb with the venturi behind the slide idea (Blue Line).

I am still working on tuning the EI carb and haven't completly given up on the venturi behind the slide idea yet but the 24mm venturi restriction in the bellmouth concept does look promising.

TZ350

10th February 2012, 15:45

Page 430 below are interesting quote snipits, the posts should be read in full.

Re smaller case volume, I have measured one of those engines and its case com is exactly 1.3 on one side and 1.29 on the other with around 540cc from memory..
This is alot smaller than an Aprilia at 640cc.

But its case vol is relatively large in comparison to 2T technology at the time.
In a 125 project I have just finished, with a case reed, 1.3 gave the best result.
Going down to around 1.24 of the RSA spec lost around 2Hp with the reeds, no matter what I did with intake length and petal stiffness, pipe geometry or carb size.

Yamahas basic technology took big strides forward after …. the factory finally getting off the high horse and admitting Honda was right all along with 54 square, and then they added back the superior spool valve that worked so well in the old RZ …

In order to take full benefit of a large crankcase volume you need free-flowing transfer ducts. That means: large cross sections, short gas column lengths and large time.areas.

Skinny exhaust pipes, high crankcase compression and narrow transfers with timings over 140° were common in the sixties.

These factors were interdependent: the skinny pipes hardly produced any decent exhaust suction, so you needed the pumping action of the small crankcase volume. And because of the narrow transfer windows you needed long timings to get anywhere near workable time areas.

The energy of a moving gas or mixture column depends on its mass and its velocity. In ducts with large cross sections the flow velocity does not rise too high because the crankcase pressure can drop fairly rapidly.

In short, narrow ducts the velocity will rise all right, but the mass in the ducts will be small. And in long, narrow ducts the long plug of gas will resist acceleration and will only slowly come up to speed. Because long columns are such slow starters, the kinetic energy at the latter stage of transfer will only make up for what went missing at the initial stage.

Here is my first thought. The carb inlet length is still too long though, so you would have to try steeper exit divergence to shorten this up.

Try putting the venturi directly behind the slide like Lectron did - this will shorten up the divergent length with much slower angles out to the RV port area.
Easy to test the flow capability of the varying venturi positions and divergent angles on a flow bench before hitting a dyno.

Yes, make it into a bellmouth. That will get you both a shorter unit and a better inflow. You might also consider putting the restriction in the bellmouth if your rules allow it. That would mean you can have a considerably longer trailing ramp (the widening can start right after the bellmouth, i.e. under the throttle slide). It also means that only the air, not the fuel, has to pass through the restriction. That way the total mass that has to be accelerated through the restriction, will be about 8 % less.

A dyno graph comparison of the OKO with the 24mm restriction in the bellmouth like Frits suggested (Red Line) and the EI carb with the venturi behind the slide idea (Blue Line).

He made a reed set up that had large stuffers down each side of the block.
The logic was that Yamaha's reed was way too big, loosing a heap of velocity as the flow exited the manifold.

There are so many interesting posts with mag articles and pictures from husaburg that its worth trawling through his “View Forum Posts” list.

The decade pages 420, 410, 400, 390 etc ….. have their own collections.

wobbly

10th February 2012, 18:07

husaberg

10th February 2012, 18:29

That is exactly the issue everyone has had with Lectron and EI carbs.
Get the mid spot on and the top will be rich, jet the top correct and the mid will be lean - no matter what needle is used.
I have said for years that a solenoid powerjet ( or adding a proper air correction system) would fix everything, but that needs alot of work to set up, so has never been done.
Its worth doing though, as the nice atomisation of the Lectron setup is worth having.
Another route would be a powerjet with air correction, these are available - I will post a link here when I find it.
Another possibility is the company that bought the patents from Edmonson - the guy who did Lectron and EI.
These new carbs won everything at Pikes Peak where they ran.
The 2T Quad had my pipes and was easily the fastest on the hill - listen for the screaming Banshee.

http://www.youtube.com/watch?v=ZneHutHgUi4&lr=1&user=motovox

Here is the air corrected powerjet setup - I have a pair and will test these on the first F3 - 400 engine on the dyno

http://www.thunderproducts.com/dial_a_jet.htm

Here is some more stuff i sent TZ a while Back

 http://www.psipowerinc.com/mxAtvCarb.html (http://www.psipowerinc.com/mxAtvCarb.htm)
257214257220

heres the other offshoot of the lectron lake etc
http://revmasterautomotive.com/revmasteraviation/?p=221

seen these talked about never a look though.
257215
http://www.aeroconversions.com/produ...arb/index.html (http://www.aeroconversions.com/products/aerocarb/index.html)
257216

Plus another
257222
http://www.psicarbs.com/bigair.php

http://www.saltmine.org.uk/dale/dale-faq.htm
Eplanation here "
The Lectrons have a central fuel outlet, that being the needle area. The needles controlled all fuel now with the exception of the power jet. One of the ideas was to eliminate the rich and lean spots in the fuel delivery curve as can happen with a multi-area delivery device such as a normal carb. The other was to make a system that was easy to adjust. Lectron succeeded brilliantly in one area, failed miserably in the other.

Fuel control was with the needle. A taper was ground into the needle on the side that faces the intake area of the engine. Needles were graded and marked 5-3, 6-1, 6-2 etc. These numbers were easy to understand. The first number was the overall richness of the needle. A 5 series was leaner than a 6 series. The second number was the midrange richness. A -3 was richer than a -1. The very top end was controlled by the power jet exactly as we understand power jet function now.

In order to have a "base" point that tuning could be initially set to, a distance was specified as standard, a datum. This was the length of the needle from the adjusting nut(what would be the needle clip in a Mikuni) and the tip of the needle that extends into what would be the needle jet in a Mik. The "needle jet" was not adjustable, much like the TMX style of Mik. The standard length was 1.945" or something like that. If the length was longer, the overall fuel was leaner as the taper would be lower and this would allow less fuel for any given throttle opening. The opposite was true if the needle length were shorter than 1.945". I think that if you had to go more than 2 turns in either direction, it was time to change the needle for a different fuel curve. This allowed for the fine adjustment of fuel.

If one were to replace the screws holding the top of the Lectron with snap clips to allow quick removal of the top, a minor needle adjustment with power jet swap could be made in about 2 minutes for 2 carbs. This was one of the Lectrons strong points.

If jetting was ok in the mid-range but off a bit just before power jet came on, you wouldn't want to adjust the needle as this would upset the balance with the mid-range. You would select a needle with a different second number - 1, -3 etc. THIS is where the Lectron failed. The quality control of the grinding of the needles was such that even though you had two needles marked the same, it didn't mean that you hade two needles that were the same. At first this caused all kinds of confusion as one would change the needles expecting a change in a known area and the engine wouldn't run anything like what was expected. Only after measuring the needles very accurately at absurdly small stations were we able to ferret out that Lectron needles were ground by the firm of "Byguess and Bygolly"!

The only way to solve this problem was to carefully hone stone the needles and hope that the results gave you a pair of needles that could be used together, run them, grade them, and hope that one was fortunate enough to get a selection after a while. With all this tuning work done to the needles, it's not hard to see that if one had a good set, they didn't get loaned out at all(Hey! I need as set of 6-2's. Got any I could borrow for this race?) Might as well part with your right arm once your friend figures out your needles work better than his!

On of the other strong points was that without a pilot circuit, the Lectrons could be run at absurd angles(35 deg) compaired to the Mik's. This allowed the carbs to be mounted to a straight manifold on the Super-street RD's for a more direct shot at the intake. If a Mikuni was mounted this way, it would flood horribly under hard braking as fuel poured out of the pilot circuit. This was not a problem with the central fuel point on the Lectron's.

But time moves on and the quality control finally caught up to Lectron(and some other problem with finances or something). Carb technology advanced as well and we have very good, though expensive stuff now that needs computers to do all the thinking where us mortal humans did it before. This is progress...I think."

http://www.ozlaverda.com/what-s-an-e...or-t15-10.html (http://www.ozlaverda.com/what-s-an-ei-caburetor-t15-10.html)
257217

I knew i had seen this somewhere explanation of the "cheater" Carb for controlled carb classes
http://lectronfuelsystems.com/faqs.html#Tuning
What is a Lectron High Velocity Carburetor?
The standard Lectron carburetor has a 2mm taper. For example a 40mm carburetor will start out 40mm and taper down to 38mm at the fuel pick up then taper back up to 40mm. The Lectron High Velocity carburetor has a 4mm taper. For example, a 38mm HV carburetor will start at 40mm and taper down to 36mm at the fuel pickup then back out to a 38mm. This carburetor was first designed for racing classes that had a restriction on carburetors size. This was Lectron’s answer to have a small carburetor work like a big carburetor. The Lectron High Velocity carburetor is also used today for bikes that do not have much “port speed”. Engines with a small amount of port speed have trouble picking up fuel efficiently this carburetor corrects that. Final note, many people put Lectron High Velocity carburetors on engines not understanding why? Just because of the name “High Velocity” they think it is a better carburetor than the standard Lectron.
Don’t confuse the issue.

History of Reds Carbs from what i understand Red or his son was in business with one of Kenny Roberts sons. Wob would know for sure, but i think his son may have worked for KR.
History Behind the AFT Carburetor

Since the beginning of the combustion engine, man has had a natural desire to get as much power out of the wide variety of motors manufactured for work and play. For the past 37 years, William “Red” Edmonston has chosen the motorcycle as his passion for power and speed.

Red started racing Triumph motorcycles in the 1940’s and after 13 years of racing and breaking bones, he decided to move to California and work with Triumph as a road manager as well as open a Honda dealership to provide for his young family. During the 1960’s, Red continually became frustrated with the fuel delivery systems for the motorcycle industry. Most of the carburetors being manufactured and sold on motorcycles were complex to tune, and required a constant effort to keep tuned for proper operation of the motor. This was primarily because of the multiple and overlapping circuits (different jets for the differing throttle positions) that caused the air fuel mixture to be very rich at different throttle positions. These early carburetors could not adapt for altitude changes either, which added to the constantly differing air-to-fuel ratios and tuning problems. Besides the frustrations that many had with keeping their motorcycles running at optimum, these crude fuel delivery systems also cause the motor to run very inefficiently and with significant harmful emissions.

In the late 196o’s, after many years of racing, managing race teams, and selling motorcycles, Red began his long career of inventing, designing, and manufacturing carburetors for the motorcycle industry. In short, Red has had a significant impact on the motorcycle industry over the past 40 years. Red has held nearly 100 patents and has invented and manufactured nine different carburetors, each of which has shared some similarities while each subsequent model continually added improvements in functionality and performance. The history of the Red Edmonston’ carburetors spans many years and a great deal of experience and improvements:

· 1968-1969: The Lake Injector prototype and final production model carburetor.
· 1970-1971: The Pos-A-Fuel prototype and final production model carburetor.
· 1971: The Pos-A-Fuel with remote float bowl production model carburetor.
· 1973-1974: The Lectron prototype and final production model carburetor.
· 1976-1977: The E.I. Prototype and final production model carburetor.
· 1978: The Blue Magnum production model carburetor.
· 1980: The Bank of Four Blue Magnum model carburetor.
· 1981-1982: The Qwik Silver prototype and production model carburetor.
· 1982: The Qwik Silver Bank of Four carburetor wins Daytona super-bike race.
· 1993: The Qwik Silver II production model carburetor (sold to Edelbrock).

Lastly i think Mike Sinclair was meant to be a gun out sorting out Lectrons i read somewhere. I guess possibly through the Roberts days connection exposure.

This is why nobody likes you Dave.
Speedpro i think you way be selling Dave a bit "short" i suspect there are numerous other reasons:laugh:

Anyways, I'm not using any queer daigo carbs,
I hear he has quite a following with both the Italian and Homosexual community.:chase:

dinamik2t

10th February 2012, 19:27

@ Husa

Great info, thanks!!

@ Wobbly

257219

:p:p

TZ350

10th February 2012, 19:41

There it is, Wobblys name on the side of the Quad ...... :niceone:

TerraRoot

10th February 2012, 22:13

http://www.minskparts.com/Minsk%20spare%20parts/k%2065%20carburettors.JPG
how about a pekar carb? for shortness at least.. not sure about the rest.. but at 23$..

Frits Overmars

10th February 2012, 23:00

...the moped rules stated for example that the carburetter should not be larger than 20 mm.

thats a pretty small carburettor, be hard to get a bore size of more than 8mm.

This is why nobody likes you Dave.
I do. At least Dave has proven he can read the way you should read a rulebook :niceone:.

husaberg

10th February 2012, 23:11

I found this as well a while back but how often is a bucket at constant full throttle anyway.Bear in mind he is a Diesel pig guy and the motors he is referring too are used more commonly for "industrial uses"
http://www.oldminibikes.com/forum/honda-clone-engines/15759-little-useful-info-before-ordering-cheap-mikuni-carbs-2.html
With the mikuni it works the same way. I also run Lectron carbs. They come standard in what ever size you want. I have had a 34mm regular model, then they have a HV model. The HV has a venturi in it. It starts off 36mm, then goes down to 32mm, then finish at the back at 34mm. This allows a rush in flow and no drop off on a instant full throttle.

The flow test has been done about 10 years ago in jr dragster racing, and kart racing. The 28mm Mikuni that everyone know and loves was tested against a HL380 tillotson carb. The 28mm Mikuni is 28.5mm all the way through. The tillotson carb is 28.5mm at the back, but with a 1"/25.4mm venturi.

At instant part throttle the mikuni flowed more air
At instant full throttle the mikuni flowed more air
At constant part throttle the tillotson flowed more air
At constant full throttle the tillotson flowed more air

The reasons why the test went this way is just like you said. The mikuni flows more unrestricted flow at instant throttle. But at constant throttle the venturi speeds up the flow. Something like going up hill entering the carb, then coming down hill into the bore.

Now at the dyno session:
The motor test was a 20+hp jr dragster flathead motor. The 28mm Mikuni carb worked very good at part throttle, and full throttle. The down falls of the carb is that the carb had to setup on a medium setting. Meaning that you was 100% sure if the carb was setup as best as can be. It was setup to only please the dyno guy. The carb didn't bog, hesitate, or sputter. So that's what matters when setting up a miknui multi jet carb. If you can crack the throttle and it doesn't bog, and revs up your basically satisfied with it as is, not knowing if it's as best as can be. Mainly because there isn't a way to tune for bottom end, and top end.

Now with the HL380 tillotson carb it was setup to work 100% correct to the motor. Reasons why is because it has it's own separate jet/needle for the high and low. So it ran perfect on both bottom and top. Giving it more bottom end TQ, top end HP, and more RPM from having more air. Being able to tune on the fly is key to getting the most possible RPM/HP you can get.

Now I use to run a 29.5mm Ibea carb back 3 years ago on my modified gx200 motor. The motor turned 10,300 RPM. At the time no one believed me because it was unheard of. The guys I was building half midget motors for have never got there motors to turn over 9,600 with 28mm Mikuni's. But the Deco 1/4 midget guys were turning over 12,000 RPM with Ibeas on them.

Ibeas are just like the tillotson carb, but MOST of them DON'T have a venturi in the carb. But they are only used on full all out high RPM race motors.Usually 2 stroke kart motors.

The 2 best carbs ever made are the Lectron, and the Ibea.

koba

11th February 2012, 16:05

More out of interest than anything else I had a look for info on "Fish" Carbs.

Kind of cool, used to be the hot setup for archaic turbo setups on Volkswagens.

My Dad had an old one, It's pretty smart and works well!

http://www.fireballroberts.com/Fish_Story.htm

TZ350

11th February 2012, 19:07

257280

Spent all day on this carb and just couldn't get it right, maybe the 33mm throat at the slide is to big. Even when it ran well it was 1-2hp down all through the range compaired to the OKO setup.

257281

So switched back to the OKO and found the lost ponies.

I got my 24mm flatslide OKO carb $69 USD from here:- http://www.treatland.tv/OKO-s/84.htm

The "RDR intake for small motor cycle 30mm" $15 USD has the right size rubber for the 22-30mm OKO's.

Cable choke conversions are available $19 USD and Boxes of Main Jets, Needles or Pilots are $24 USD a box of 10.

The Suppliers Treatland, http://www.treatland.tv/ are in San Francisco, delivery International $43 USD (to me in NZ anyway) 5-10 working days.

A std OKO carb is bored straight through without any taper, so a 24 is 24 at the back right through to the front. OKO's are made from an alloy that does not crush easily when held in the lathe and the alloy machines very nicely unlike the usuall pot metal carb bodies of Keihin, Mikuni, Amal etc.

257303

OKO's are great carbs to work with, I have had more success with them than any other carb and I have tried a few, big, small and every thing inbetween ....... the Treatland guys are a great bunch to deal with. http://www.treatland.tv/

Being touted on the net are inferior pot metal Chinese knockoffs of the Taiwanese OKO, so it pays to check.

husaberg

12th February 2012, 16:23

The interesting thing is, that the signal strength was much greater and we had to reduce the main jet, we went from 140 down to 100 which is the smallest we could get, made 31rwhp with the 100mj, maybe there is more if we could get smaller jets.

Your friends here at Treatland do them Rob
257314

<tbody>

<tbody>
for use in the OKO carburetors. 10 pack small range jet box come with jets 80, 85, 90, 95, 100, 102, 105, 110, 115 & 120.

comes in a handy flip top clear plastic box

"OKO - new yuppie fashion trend"

</tbody>

</tbody>

<tbody>

</tbody>

I was surprised to find that it was in the USA because the site has some err....intersting turn of phrase.
http://www.treatland.tv/OKO-main-jets-small-range-p/oko-10-pack-main-jets-small.htm

(http://www.treatland.tv/OKO-main-jets-small-range-p/oko-10-pack-main-jets-small.htm)

TZ350

12th February 2012, 17:56

257323

Looking at any carb selection chart you can see why the Bucket rule makers thought a 24mm carb would limit a 125 2-strokes power output. They didn't expect the cleverness of Thomas the Vietnamese race mechanic or the workshop skills of Bucket ..... :laugh:

I think that between us all on Team ESE we have put in about 5-6 of months work lately, or maybe longer and a lot of dyno time finding a good carb/inlet system configuration.

257347 http://www.treatland.tv/OKO-s/84.htm

The OKO carb, is easy to hold in a lathe and machine.

257325

The 24 measures 24mm in front of the slide and is easy to taper bore out to 30 or even modify with an insert in the bellmouth for extra width at the slide.

257321

30mm is about as big as a 24mm OKO can be taper bored out to.

257322

This is the EngMod2T model of my current inlet system. The 30mm max limit at the engine end of the carb sort of limits the angles possible.

By having a bit of a steep divergent angle after the 24mm venturi maximises the throttle area.

This carb has produced the best numbers on the dyno so far but has yet to be tried out on the track......

257338

The fastest bike we have had on the track ran this 24mm OKO taper bored from just behind the slide out to 30mm at the manifold and that worked OK. One day we might get to try a back to back test on the dyno.

TZ350

12th February 2012, 18:03

I was surprised to find that it was in the USA because the site has some err....intersting turn of phrase.
http://www.treatland.tv/OKO-main-jets-small-range-p/oko-10-pack-main-jets-small.htm
(http://www.treatland.tv/OKO-main-jets-small-range-p/oko-10-pack-main-jets-small.htm)

Yes, interesting bunch of Guys, mostly into racing Mopeds and over the road is a motorcycle workshop that specialises in 70's and 80's Hondas, there was about 30 bikes parked out side, there were several CB77's and K1 350's and 750's, in fact I saw a lot of older bikes around San Fran including a couple of water buses when I was there late last year.

cotswold

12th February 2012, 20:35

TZ350

12th February 2012, 20:49

Is there any difference between the
OKO K-102 24mm FLAT SLIDE POWER-JET RACE CARBURETTOR
and
NEW OKO 24mm FLAT SLIDE POWER-JET RACE CARBURETTOR

both sold by the same supplier with a difference in cost of about $20
It can't just be the float bowl as the 102 comes with either

I thought it was the float bowl, it may be just a marketing ploy, you may have to ask them and see if their answer makes sense.

Anyway they get modified so it probably doesn't matter much. We use a plastic bowl to check the actual float/fuel hight and the metal one out on the track.

Don't forget to get a flange type rubber manifold for it too, the original GP one is to small for the OKO.

Henk

12th February 2012, 21:04

ProbabLy is just the float bowl. You know you want the flashy clear one. Get the black carb to go with, looks cool so must be faster.

cotswold

12th February 2012, 21:07

ProbabLy is just the float bowl. You know you want the flashy clear one. Get the black carb to go with, looks cool so must be faster.

I know why you want me to get the clear one and it is just not sporting!

I have asked the question of the supplier so should get a diffinitive answer over the next couple of days,.. Black would look cool with my planned colour scheme

husaberg

12th February 2012, 22:09

I don't know the quality of these but i seen somewhere how to pick the better ones it was something to do with not having allen Screws and something else i forget.

These cover a wider range of sizes than i have seen for the ones on the net elsewhere.

Available here http://www.akunar.com/CARBURETTORS.html

Also here some Honda stuff whats the secret HRC

Yoichi Oguma was the Vice president of HRC was hands on and often seen at the track.
He retired the next year early to have his back fixed.
He was one of the original Honda NR500 test riders he gave up the test riding after testing one of the original NSR500 for built for Freddy. I Don't blame Him either.:doctor:

husaberg

12th February 2012, 22:14

TerraRoot

12th February 2012, 23:48

Is there any difference between the
OKO K-102 24mm FLAT SLIDE POWER-JET RACE CARBURETTOR
and
NEW OKO 24mm FLAT SLIDE POWER-JET RACE CARBURETTOR

both sold by the same supplier with a difference in cost of about $20
It can't just be the float bowl as the 102 comes with either

and the lack of powejet circuit?
i've a motoforce 24mm, didn't know it was a motoforce until i got it, filled it with much better oko jets, the motoforce jets were plated with some sort of shiny/silver stuff and the oko jets were good old fashioned plain brass. the thread in the big nut on the float bowl is horrendous.
next one will be an oko

Brian d marge

13th February 2012, 02:46

Grumph

13th February 2012, 06:32

I work at Asaka, ( actually it s asakadai , next station up ) and I can vouch for that article ,

Photos are banned and as much as I try , no joy in getting in

seriously it ain’t flash , you have the skills in Christchurch to do better , if you lot weren’t so individualistic

I remember one listening to the Engineer who designed the cbr 6 , going on like it was the best thing since sliced bread , and me thinking that there was better being built opposite the boat sheds

Stephen

Which boatsheds Stephen? Are you referring to the ChCh public hospital maintenance workshops by any chance ?
And getting any two Kiwi motorcycle racers to co-operate on a project is nearly impossible unless one has money....

F5 Dave

13th February 2012, 11:50

. . .

Here is the air corrected powerjet setup - I have a pair and will test these on the first F3 - 400 engine on the dyno

http://www.thunderproducts.com/dial_a_jet.htm
Really? I'd seen this ages ago & dismissed it as marketing hype, just sounded too good. But open to hearing if there is something to it.

koba

13th February 2012, 16:53

Really? I'd seen this ages ago & dismissed it as marketing hype, just sounded too good. But open to hearing if there is something to it.

Funny shit, completely independent of that my Dad and I had thought of doing a similar thing. When I was repairing the broken powerjet takeoff on my carb we were talking of the possibilities of adding a mixture screw to both the power and main jets. It got put on the "Maybe try it one-day" list.

husaberg

13th February 2012, 17:02

It seems little Jon was indeed less tactful than talented.
Who would have guessed that:rolleyes:
Was the Honda entourage really that small for Doohan?
I will add the Kenny Roberts training regime later i had heard of the ranch and the xr100's but never seen how it all works.

After reading this it looks like i won't make a world champion any time soon.:shifty:
Kenny rated John ahead of both Lawson and Rainey at the time on the dirt track.

crazy man

13th February 2012, 17:24

It seems little Jon was indeed less tactful than talented.
Who would have guessed that:rolleyes:
Was the Honda entourage really that small for Doohan?
I will add the Kenny Roberts training regime later i had heard of the ranch and the xr100's but never seen how it all works.

After reading it looks like i won't make a world champion any time soon.
Kenny rated John ahead of both Lawson and Rainey at the time on the dirt track.did you get my message ok ...all good?

husaberg

13th February 2012, 18:46

did you get my message ok ...all good?

Yeah Pm ed again. All Good Hush Hush. Its a secret :laugh:

I mented the VP of HRC and the NR500
The NR500 had something i believe was the first use of something that all the Moto gp bikes, i think now have, Virtual choc fish for anyone who can guess what it was?

ps it is not carbon or USD forks or Valves cams etc either:shifty:

Hint it is to do with the fact it had virtually no flywheel effect.

0257529257530257531257532

It failed, but a least they tried to do it as an even match 500cc vs 500cc

Bert

13th February 2012, 20:29

Funny shit, completely independent of that my Dad and I had thought of doing a similar thing. When I was repairing the broken powerjet takeoff on my carb we were talking of the possibilities of adding a mixture screw to both the power and main jets. It got put on the "Maybe try it one-day" list.

Little RC planes have a right angle fuel adjuster screw/tap thingies with needle valves. I'll try and dig out a photo. but it would be very easy to introduce one into the mix as adjustable power jet.

none on here but check out the datalogging fuctions:eek::
http://www.hobbyking.com/hobbyking/store/__4575__MicroPower_V4_E_Logger.html

LiPol batteries (4 cell = 14ish Volts):
http://www.hobbyking.com/hobbyking/store/uh_listCategoriesAndProducts.asp?idCategory=86&LiPoConfig=4

2T Institute

13th February 2012, 22:01

The page that didn't fit plus some other stuff including something that backs up Dave's claim that they are in bed with the devil.
Kenny Roberts quotable as always.

I don't think Honda did have anything that special other than a well developed bike
It did have a ignition and power valve curve which was adjusted dependent on what gear and throttle opening, but i guess they all had that by then surely Cagiva did I think and i hope Yamaha did.
I guess the ignitech could possibly do this Wob?

Roberts fell flat on his arse when he had a go of making his own engine. Wasn't until he hired (ironicaly) Oguma-san and ex Yamaha GP engineer Yoda-san(I forgot his firstname) they redesigned the engine to be shorter, narrower and increased the V angle and incorporated a balance shaft did that Modenas start to go like a GP bike. The shorter and narrower engine allowed a longer swing arm which gave better traction made it handle like a GP bike. That all came to naught when the 4T rules were announced a short while later . In which the cycle began again, best results were with the HRC V5 and some pointers on frame flex.
HRC always seem to perform best when there is a stern hand on the rudder, though with a smart cookie like Nakamoto they should be winning for some time to come.

A Zeeltronic has Pulse Width Modulation (PWM) on soleniods (can use air or fuel), to map in each gear with the Ignitech RACE you need to install a 6 or 5 position switch. The NSR250 has on standard as a part of the speed limiter the RGV has one as an optional race kit part. Both replace the neutral switch at the end of the shift drum. Would not be hard to make just time consuming to get reliable.

sonic_v

14th February 2012, 04:43

Interesting radio program about Ernst Degner.

http://www.bbc.co.uk/iplayer/console/b01byhrg

teriks

14th February 2012, 05:41

Little RC planes have a right angle fuel adjuster screw/tap thingies with needle valves. I'll try and dig out a photo. but it would be very easy to introduce one into the mix as adjustable power jet.

none on here but check out the datalogging fuctions:eek::
http://www.hobbyking.com/hobbyking/store/__4575__MicroPower_V4_E_Logger.html
<snip>
The Eagle tree logger works quite well, at least in my clean environment.
I'm using the flight pack, but this one might be more suitable for road going stuff:
http://www.eagletreesystems.com/Car/car.html
Example output below

koba

14th February 2012, 06:19

A Zeeltronic has Pulse Width Modulation (PWM) on soleniods (can use air or fuel), to map in each gear with the Ignitech RACE you need to install a 6 or 5 position switch. The NSR250 has on standard as a part of the speed limiter the RGV has one as an optional race kit part. Both replace the neutral switch at the end of the shift drum. Would not be hard to make just time consuming to get reliable.

I think FXR's have them for the gear indicator.

wobbly

14th February 2012, 07:10

The Ignitech has only 2 possible curves embedded in the ECU,but these can be chosen many ways including using the system HRC instituted on the road and race bikes with
a simple 5K pot on the drum shaft - easy to install and reliable as any electronic part can be in an automotive application ( an auto TPS would work fine).
Thus the best setup is a curve for 1st,2nd,3rd gear,then another for 4th,5th,6th where the acceleration rate is lower.
I havnt looked, but I dont think a Zeel has 6 possible curves like a PGM F3 can do.

Re the powerjets, I tried years ago to add air correction to a powerjet on a Lectron with a needle valve on the fuel flow.
I couldnt get it to work as the air bleed I had was way too big, and all I got was intermittent fuel/bubbles coming out the nozzle.
The air hole was around 0.3mm, needed to be less than 1/2 that I think.
The perfect setup would be a needle valve on both the fuel and air correction orifices, or even better a solenoid on the fuel that could be PWM'd.

F5 Dave

14th February 2012, 08:39

Be interesting to see how these things go then.

TZ350

14th February 2012, 09:33

Re the powerjets, I tried years ago to add air correction to a powerjet on a Lectron with a needle valve on the fuel flow. ... The perfect setup would be a needle valve on both the fuel and air correction orifices, or even better a solenoid on the fuel that could be PWM'd.

257539

Attached to the float bowl is a large adjustable needle jet purchased from a Model Shop.

Gigglebutton

14th February 2012, 10:35

257539

Attached to the float bowl is a large adjustable needle jet purchased from a Model Shop.

Hey Rob will the needles and bits off my 26mm Lectron fit. You are welcome to try.

Dazz

TZ350

14th February 2012, 15:15

257553 257582

Thanks Daz for the offer but after exploring quite a few carb's and different configurations I have settled on our own style of taper bored OKO carb. I have managed to get more power out of one of these than anything else I have tried. Hopefully it will drive well on the track too, we are taking the beast to Te Puke, so will know soon enough.

husaberg

14th February 2012, 16:01

I think FXR's have them for the gear indicator.

I think dirty old GN250's had one as well. Well pretty sure. I am trying to forget ever having ridden one once.
257557
Not that anybody would ever use GN Suzuki parts on a race bike:rolleyes:
Imagine someone having a GN based race bike oh the shame.:laugh:

TZ350

14th February 2012, 16:33

Bert

14th February 2012, 17:43

wobbly

14th February 2012, 18:24

Yep, thats easy,Aprilia RS250 has a splitter box for the throttle/carbs/PV oil pump drive cables - with a TPS pot connected directly to the throttle cable.
But all the shift drum pot does is tell the ECU what position the drum is in by changing resistance for each gear - the software takes that info and selects the appropriate curve 1 or 2.
That GN cable looks like a multi position neutral type sensor - not a continuous pot.
But this would also work to tell the ECU when 4th gear + is selected by connecting that input to ground.

Buckets4Me

14th February 2012, 18:53

Imagine someone having a GN based race bike oh the shame.:laugh:

not just that but bragging about it as well :laugh:

husaberg

14th February 2012, 23:08

I had seen these and i was going to do one from a Rover they have a pressure one.
Pressure Relief Remote Thermostat

(http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=257614&d=1329218519)http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=257614&stc=1&thumb=1&d=1324193035 (http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=257614&d=1329218519)
(http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=257614&d=1329218519)
From TechWiki Jump to: navigation (http://wiki.seloc.org/a/Pressure_Relief_Remote_Thermostat#mw-head#mw-head), search (http://wiki.seloc.org/a/Pressure_Relief_Remote_Thermostat#p-search#p-search)
A Pressure Relief Remote Thermostat (PRRT), or sometimes just PRT, is used to increase the amount of coolant flowing around the engine. The PRRT has a bypass valve opening when the coolant pump is flowing too much coolant for the radiator circuit. This valve is reducing pressure difference inside the whole circuit, achieving at the same time a more constant temperature inside the engine.

Note: The acronym PRT means Pressure Relief Thermostat. This setup was developed by Bill Hutchins and used by Rover, MG and Landrover, it has been in use in mid engined cars for 25 years, and an Elise system was previously developed by Simon Scuffham when racing his k-series engined elise. PRRT is actually a misnomer (albeit harmless), allegedly invented by one of the members of the Seloc forum. The PRRT acronym may not actually be recognised by anyone outside of the Seloc forum (including anyone involved in the design, manufacture or assembly of the device) though is perhaps a more accurate description as the second R refers to remote.

http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=253027&stc=1&thumb=1&d=1324193035 (http://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=253027&d=1324193312)

remote stat with by-pass BMW/Rover SD1 2600/etc

http://www.mgfcar.de/thermostat/Water_System_Mods.htm

These are the ones for a RS it is a sales spell mind ypu but the temp stuff is interesting
Temperature Management

257611257612257613

Bob Chiras
Bob Chiras Distributing
603-432-4766
bob.chiras@att.net

Over the past two years the popularity of water-cooled motors has introduced many racers to new issues relative to tuning. The purpose of going to water cooled motors has been clear for years. Motorcycles made the transition in order to lighten motors. Air cooled motors needs fins and large surface areas to carry away heat. Water cooled motors rely on the principle of moving the heated liquid through a radiator that is placed into the air stream to cool the liquid and then deliver the cooled liquid back to the motor thereby taking away the heat generated during combustion.

Having water as a cooling agent causes racers to learn that water temperature is a metric that is tunable. We have all seen race teams in a variety of race series tuning their cooling by applying tape to radiators or changing how much air flows through cooling ducts We have also learned that in many forms of performance sports that there is a necessity to manage he flow rate of the coolant. Often we have to manage liquid flow to manage cooling. We do this with ratio changes at the drive of our water pumps. The issue being that the water has to have sufficient time to absorb the heat that we are asking the water to carry away from the motor. If water flows to fast and there is little heat transfer we may overheat a motor. If there the water flow is overly efficient and carries away to much heat we face a different issue of getting incomplete combustion and the motor running poorly much like your automobile on a cold morning.

All motors need to address temperature management but because of inherent design differences there are different techniques applied. Moto or motorcycle motors and ICC motors differ in that most moto motors have water pumps built into the motor while the ICC motors rely upon external water pumps that are driven by the rear axle. As you would expect each has its advantages and disadvantages.

First the advantages; Moto motors have water pumps built in to the motor and circulate water while the rear wheels are stationary. ICC motors have no built in water pump and are typically lighter and more compact.

Disadvantages; Moto motors are designed to run at lower and less constant RPM’s than is typically found in karting. This means that the water pump is likely turning at an incorrect speed and may be moving water at a rate that is different than the design engineers planned. ICC motors have no pump circulation until or unless the rear wheels are turning. This means the motor relies on natural convection to circulate coolant while the kart is on the grid waiting for the event to begin.

Both types of motors share the issue of needing to get the motor to the correct temperature and maintaining the correct temperature for the duration of a race event. The solution must be highly repeatable, increase reliability, increases performance and be elegantly simple. The solution was the introduction of a device being used in almost all other forms of motor sports, a thermostat designed for karts and motorcycles.

The thermostat is designed to address the needs of performance racing. The design manages the water path so that large rushes of cool water from the radiator never reach the water jacket of the motor and potentially cause a cold stick. The design addresses the convection heat transfer during start up of ICC motors with external water pumps as the design can open multiple paths to mix hot and cool water. With multi flow paths the thermostat always maintains sufficient water flow through the water jacket to carry away the heat generated by combustion.

Installation is simple but it does take some planning. The thermostat installs in the upper radiator hose for the purpose of controlling flow from the motor to the radiator. However there is a need to install a bypass hose that connects the bottom of the thermostat to the lower radiator hose. This provides the flow to allow the heat dissipation to occur during warm up and it also serves to prevent the to much flow from the radiator to the water jacket of the motor. As the water temperature begins to rise the thermostat opens at a rate that allows water flow without causing excessive changes to the running temperature of the motor. We found the thermostat to be very responsive to small changes in temperature with the thermostat opening and closing to maintain the proper motor temperature.

When we tested the thermostat we applied the thermostat to a Yamaha YZ125, a Honda RS125 and a TM125 and Aprilla 125. We tried the thermostat on karts that had over sized radiators and on karts with stock radiators. Our findings were astounding. First we learned that stock radiators were always sufficient to cool even very highest performance motors from Bill Price Racing. We also learned that large radiators were overkill when we applied the thermostat. We were able to reduce the size of the radiator by almost 50% and maintain a water temperature of 120 degrees on a day when the ambient temperature was 95 degrees. Being curious and living in New England we decided to replicate the testing on another day when the ambient temperature was only 50 degrees. We found less than one degree of operating temperature with the motors.

We used Digatron DT54K Max instruments to capture the water temperatures and to track the temperature of the motor from the start of the motor to the conclusion of the race. The temperature was exceptionally stable for all of the laps. We tried the same thermostat on a road racing motorcycle with a Digatron DT52K Max and achieved the exact same results that we found on the karts. Highly stable temperatures and no need for large or expansive radiators. We saw temperatures range from 120 degrees to 128 degrees with a great deal of consistency.

What is the secret? A design that manages water flow at all times. The thermostat opens and closes in response to very small temperature changes. We found a design reflects a device intended for high performance motor sports. It is lightweight, very modular with each fitting having the ability to be removed and or replaced as needed. There are fittings that allow is to utilize water temperature probes from Digatron, My Chron or any other data collection instrument. The thermostat and all of its parts are anodized to protect it from the corrosive nature of many of the water and water treatment chemicals used like water wetter. And we liked the fact that the dealer that showed us the device had a complete stock of product available for the racers. Each fitting had its own gasket that was provides so we were not using any Teflon tape and trying to tighten fittings with tape applied.

We purchased the thermostats from Rising Sun Cycles http://www.risingsuncycles.com (http://www.risingsuncycles.com/) . They have been a force in motorcycle racing for years and came to karting through the introduction of the Battle Shifter and their line of HRC/Honda OEM Parts that are without a doubt the highest quality parts available for your moto racing motors
Installation time was less than one half hour but as with all race accessories we suggest that you purchase the unit and do the installation at home or in the shop prior to getting to the track. This assures that you have the correct hoses needed to make the connections and that you are able to check all of the fittings and clamps to be sure that the installation is neat and attractive as well as functional.

Check out the two thermostats offered by Rising Sun Cycles. The price of the thermostats are $199.95 (http://www.rscycles.com/images/thermostat/therm_guhl.htm) to $250.00 (http://www.rscycles.com/images/thermostat/thermostat.htm). If you need technical advice or want to discuss the application call Rising Sun Cycles at 860-916-3696. email Steve@rscycles.com of write to them at Rising Sun Cycles, P.O. Box 122, Fall River, MA 02724-0122 Business hours are 9AM to 5 PM EST Mon-Fri. Steve can provide you with a list of events where he or his dealers will be supplying the thermostats. . Look for the karting section of the web site.

Get one soon and manage the temperature with one of the finest devices that we have found and get rid of that oversized radiator that is adding weight and slowing you down by putting too much draw into the air stream.

PS $200 dollars buys a lot of tape.

C_Wolf

14th February 2012, 23:45

Hello
I use this, works great.
http://www.hvg-engineering.com/index.php?action=article&group_id=10000015&aid=127&lang=NL

2T Institute

14th February 2012, 23:52

257559 257560 257581

30mm at the engine end and 24mm at the bellmouth. The std 24mm OKO is bored 24mm parallel straight through, so I taper bored it and left just a 2mm length of the original 24mm bore in the bellmouth. The first part from the bellmouth to the slide is a little steeper than from the slide back to the manifold. The last 45mm is the manifold and rotary valve cover.

I suppose it's a bit late now but I like to leave 10mm at the back(engine side ) of the slide parralel also. Though I'll be interested to see if what you have done works alright.

Frits Overmars

15th February 2012, 00:12

water has to have sufficient time to absorb the heat that we are asking the water to carry away from the motor. If water flows to fast and there is little heat transfer we may overheat a motor. If there the water flow is overly efficient and carries away to much heat we face a different issue of getting incomplete combustion and the motor running poorlyCompare two cooling systems, A and B. In system B the water flows three times as fast and picks up only half the amount of heat per liter, compared to system A.
Then system B removes 50% more heat than system A! And provided your piston clearance is OK, you just cannot have too much cooling. In the Aprilia RSA125 the water pump circulates 160 liter per minute. That is 3 liter per HP per minute!

The thermostat and all of its parts are anodized to protect it from the corrosive nature of many of the water and water treatment chemicals used like water wetter.Nowadays we have a fine solution for avoiding corrosion; it's called plastic. Saves weight too.

PS $200 dollars buys a lot of tapeI don't know exactly how the NZ dollar is doing, but that sum will probably buy you two of these:
http://www.hvg-engineering.com/index.php?action=article&group_id=10000015&aid=127&lang=NL

teriks

15th February 2012, 02:47

BS. Compare two cooling systems, A and B. In system B the water flows three times as fast and picks up only half the amount of heat per liter, compared to system A. Then system B removes 50% more heat than system A! And provided your piston clearance is OK, you just cannot have too much cooling. In the Aprilia RSA125 the water pump circulates 160 liter per minute. That is 3 liter per HP per minute! That's plenty of flow, how much power does the pump absorb?

TZ350

15th February 2012, 05:39

I suppose it's a bit late now but I like to leave 10mm at the back(engine side ) of the slide parralel also. Though I'll be interested to see if what you have done works alright.

10mm parralel behind the slide also, is more or less the configuration of the carb Chambers prepaired for Av's bike and it runs fine. My tapered right through idea works on the dyno but has yet to be tried on the track, fingers crossed it works OK but I will be taking a spare carb with us to Te Puke just in case .....:)

wobbly

15th February 2012, 07:03

I have had a bunch of those thermostats made - as the Guhl price is burglary, you can have one for 150nzd delivered..
They dont "fix" a deficient cooling circuit - just regulate the temp as seen at the engine to a constant 50C, as long as the rad and pump can cool the water
to that level.
Perfect if the rad is too big, it delivers the same temp all the time with no tape needed.

bucketracer

15th February 2012, 08:44

wobbly

15th February 2012, 11:30

Bottom line is that if one were to put in 1/2 the effort and time that has been put in on that engine, but started with a modern watercooled top end,fitted a Wobblypipe of course - and
stuck Av on that, she would have smoked/lapped herself.
Remember - it was only a few years ago that I was laughed at for suggesting 30Hp from a 100 was easy if it was done right - now we have a 125 Aircooled doing it.
Its all relative.

TZ350

15th February 2012, 16:40

Bottom line is that if one were to put in 1/2 the effort and time that has been put in on that engine, but started with a modern watercooled top end fitted and a Wobblypipe of course .....

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They have the same power but, the I00cc water cooled with Wobbly pipe, red line, has a much better spread of power compaired to my 125cc air cooled engine, blue line, dam good results from a 100.

crazy man

15th February 2012, 17:30

257647

They have the same power but, the I00cc water cooled with Wobbly pipe, red line, has a much better spread of power compaired to my 125cc air cooled engine, blue line, dam good results from a 100.the big thing is will it last a GP? all will the tractors take it again?

cotswold

15th February 2012, 17:31

Farmaken

15th February 2012, 17:37

the big thing is will it last a GP? all will the tractors take it again?

2012 .... Year of the Dragon. I mean two stroke !! Bring on the GP

bucketracer

15th February 2012, 17:39

- it was only a few years ago that I was laughed at for suggesting 30Hp from a 100 was easy if it was done right - now we have a 125 Aircooled doing it....

High hp air cool ed's have been around for a while ........ 28 hp claimed by SS90 ...... posted March 09

I have ALOT of experience with this subject matter, and am willing to pass it on to..... "the boys back home"

Man, you guys are way behind....

Oh, yea, 28 P.S .....is the most I have ever seen out of an....AIR COOLED, DISC VALVED 125cc TWO STROKE.... Oh, the 28 P.S is with my own exhaust as well.....

I know alot about "DISC VALVED, 130CC TWO STROKES RUNNNING 24MM CARBS…

And..... The Primary compression ratio is 1.49:1

I have loads of dyno runs experimenting with primary compression ratios......

1.5:1 is always the best curve (long and fat)....

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28 ps (DIN hp) with 20Nm (14.75 ft/lbs) torque and about 2.5K usable power spread.

husaberg

15th February 2012, 21:20

Water Cooling! ... did anyone notice that 2-stroke at Tokoroa that ran strong all day and sounded crisp start to finish, winning every race and in the 30 lapper laped every other bike, taking them two and three at a time down the straights was ... Air-Cooled!!

No one has ever accused me of being a Rhodes Scholar. Or is likely too either anytime soon.

But.......
put someone slow on a fast bike they will generally go pretty well still, if not a maybe bit shit on the corners.

Put someone fast on a slow bike they will generally still go pretty fast just a bit shit on the straights.
But they will make up a bit with fast exit speeds and late braking.

Put some fast but pretty heavy on a fast bike they will still do ok.

Put some pretty fast on a fast bike and they will be hard to beat.

Put someone fast and pretty and light on a very fast bike and well nearly unbeatable.:shit:
If you then throw in some Handling, Well it could be construed as sexual harassment:facepalm:

Cylinder finning

I was actually looking though a old two wheels the other day and this engine which i remember seeing before caught my attention.
Can't find the mag at the moment and this is the only pic i can find at the moment sorry it is real grainy, but you will get the idea.
I am not sure why the fining is like this if it is a continuation of the strips to stop the fins ringing or partly for strength but it got me thinking.

The old space frame John Player Norton with a fairing had a should around the engine to direct air flow through the fins the fins. Instead of going past or around the engine.

This engine a minerilli I think could do the same it would also give additional fin area easily.

I think planes sometimes have the raised tips on the end of a wing to stop the air spilling over the ends
257678

as do a lot of foils on race cars.
257679
I see also there is many factors to play with if you delve into wing designs with the shape of the individual fins the texture as well as the end shapes and angles of the fins (wings)

I would still, like to see an radial Sunburst or porcupine finning on the head.
Or you could just use liquid cooling but then you will have to lose 25cc or so:innocent:

Also found this pic of Mr Thiel
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Frits Overmars

15th February 2012, 22:59

....Also found this pic of Mr Thiel
257682You want pictures of Jan? Then here are two; one from 1960 (note the riding number...), the other one 50 years later.

Brian d marge

15th February 2012, 23:42

Very quickly, with fins , look at the heat path and the materials it crosses, also the air flow between the fins , and the amount of heat each fin can remove,

Heres a paper on fins , hope this helps

Stephen

dinamik2t

16th February 2012, 02:21

Has anyone tried a relocated ring peg?
Frits once informed us that there is no problem when the ring opening passes above the boost port (up to a certain width though, which I don't remember - definately more than 15-16).

I had an old piston lying around and gave it a try. Old peg was positioned 11mm from IN center and protruded -0.6mm from the piston surface. I drilled a new hole -1.5mm- and my intention is to fit in a 1.6mm drill.
Do you think it will endure the forces of the ring and that it will stay in place?

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Also, Frits or Wob, you think that a radiused carb bellmouth like below (pic on the process) could have a positive effect?

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wobbly

16th February 2012, 07:00

Re that power graph from March 09 - run that engine on the track against the Aircooled of TeeZee and it would get smoked easily.
Apart from the new engine having 10% more power, it will spin to 12500,the other, lucky to spin to 10500.
On a sprint track the new engine would have say 3 more teeth on the back,this would destroy the other bike off corners and reach the same top speed way faster.
On a long track the extra 2000 rpm and power band width, means no contest at all.

The piston pin move - drilling down from the top was how Yamaha did it for years in the TZ engines.
They also drilled a short hole into the skirt, where the pin pushed thru, and bent the end inwards into the hole,making it impossible for the pin to fall out.

Shortening the carb bell may be a good move if the intake tract is already too long,but any sharp edge will create turbulence - even at the outer extremes.

TZ350

16th February 2012, 07:24

Hi Rick52

This is the piston we were talking about for TF/TS's, forged piston, 1mm rings and 14mm pin.

Use one ring keep the other for a spare. The piston skirt on these forged pistons can be cut back safely.

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Ned Kelly got his one from Jawzys on Ebay for $82.48 plus $32.25 shipping. Jawzys seem to have a selection and are worth a look.

http://www.ebay.com/itm/Wiseco-Piston-Kit-Suzuki-TC125-70-78-57-5mm-/220616513206?pt=Motorcycles_Parts_Accessories&vxp=mtr&hash=item335dc4d6b6

Wiseco 449M05600 449M05650 449M05700 449M05750 for Susuki 125 TS, TC DS replaces 449Pxx

Haufen

16th February 2012, 07:41

TZ350

16th February 2012, 08:50

TZ, did you happen to test a bigger carb, say about 35mm on your engine? I know this is not allowed by the rules, but this way you could elaborate how much power you are down because of the rulebook. If it should turn out you have gotten pretty close with your current 24mm setup (which is my feeling), you could move on and concentrate on another area on your quest for a more powerful engine.

Test a biger carb, that is a good idea and was also suggested to me by Speedpro and Kel. It is something I intend doing but its a bit harder to implement in practice as putting a much bigger carb on a small inlet port/tract may not tell us much, as the whole inlet system needs to be in balance.

EngMod2T tells me this is the area to concentrate on for now. The simulation software has given me the numbers for the complete engine (posted earler) but implimenting them in the real world of metal is a bit of a challange.

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I have tried a 24/38 that flowed much more air on the flow bench than the 24/28 did, they both had the same outlet diameter. But when I tried the 24/38 on the dyno, it did not make any more power than the 24/28 suggesting the holdup is some place else and modeling with EngMod2T pointed to the size of the rotary valve inlet port itself.

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Anyway the 24/38 was to long and is the reason I made the 33mm blue IE carb with the 24mm venturi placed at the back of the slide, any way that didn't work as well as the prototype taper bored OKO. Its been a lot of work but you have to go the extra mile to get anywhere.

I am making changes to the RV port and could re work the prototype 24mm OKO I bored and modified with glue in the bell mouth and bore it out further to 30mm. That would make an easy back to back test like you suggest with the new 24mm taper bored OKO as they are both 30mm inside diameter at the engine end, but it may only tell us that a taper bored 24 is nearly as good as a conventional 30.

Slapping on a bigger carb might be easy but its the complete inlet system that has to be changed for a meaningfull test .... a 34 is just to big at the engine end to be an easy thing to try properly.

Once I have sorted the inlet system, got my tripple port cylinder and Wobbly pipe on and working, my quest will not be more power although I am sure its there. But a wider power spread, at the moment its 4k ish but another k would make this a much more rideable bike on short tracks.

I would also like to make a new triple port cylinder liner, not for more power but power spread by reducing the exhaust port duration while still having the current ex port and blowdown time areas and improve the mechanical reliability by having a narrower main exhaust port, something around 65-68% of bore diameter to give the ring an easier time instead of the present 75%.

EngMod2T indicates the inlet system as a whole is the most fruitfull area for me to work on at the moment.