ESE's works engine tuner

[richban]

Dad's got me and Thomas dialling in his bike on the dyno.

231627

Blue = new side port cylinder, Red = Old cylinder

Starting to clean the power curve up nicely but the clutch slip has come back......

So close to the magic number. Nice work. It would be interesting to do a back to back with my bike when the new engine is back in.

[gatch]

Comparing costs/hrs involved would be interesting too.

[Yow Ling]

Comparing costs/hrs involved would be interesting too.

might be interesting but not really relavent, you cant win a race on a three legged horse, some people think thats what buckets are supposed to be , but they wrong

[Kickaha]

you cant win a race on a three legged horse

What if it was a race for three legged horses?

[gatch]

might be interesting but not really relavent, you cant win a race on a three legged horse, some people think thats what buckets are supposed to be , but they wrong

I think it's entirely relevant.

For those that aren't clued up on the ins and outs of building competition engines.

Like me.

[Buckets4Me]

Comparing costs/hrs involved would be interesting too.

cost hours devided by 4 bikes is not all that much :innocent:

but it's the ideas you need ! :shit:

and being open minded about new idears
(that copper dosent look so silly now)

[richban]

Comparing costs/hrs involved would be interesting too.

I was more thinking of comparing dynos. They are not all created equal.

Cost/hours just equals lots. Best not think about that. Its all just fun playing with motors.

[Buckets4Me]

So close to the magic number. Nice work. It would be interesting to do a back to back with my bike when the new engine is back in.

that would be telling indead
and if your bike is ever up this way I'm sure they would love to put it on the dyno and see what the difference realy is

I'm sure there would be a few interested people out there :corn::woohoo::drinkup:

[TZ350]

Comparing costs/hrs involved would be interesting too.

230+ pages is a bit of a clue.........

It always seems to cost more than it should and take longer than one wants, but once we have figured it out, making copies for the rest of the team is usually much quicker and fairly easy.

Books and the net have been explored for pointers and anything seemingly worth while posted here.

All the cost and effort is in following up on ideas sorting out the good ones.

The engine and chassis work has mostly been done with basic hand tools, the sort of thing a home handyman might have.

And everything we have done has been posted on this thread, so pretty much anyone interested in 2-Strokes can copy it if they want to.

For us things started to move ahead when we realised the importance of BlowDown-Time-Area.

[koba]

230+ pages is a bit of a clue.........

It always seems to cost more than it should and take longer than one wants, but once we have figured it out, making copies for the rest of the team is usually much quicker and fairly easy.

Books and the net have been explored for pointers and anything seemingly worth while posted here.

All the cost and effort is in following up on ideas looking for the good ones.

The engine and chassis work has mostly been done with basic hand tools.

And everything we have done has been posted on this thread, so pretty much anyone interested in 2-Strokes can copy it if they want to.

For us things started to move ahead when we realised the importance of BlowDown-Time-Area.

That teamwork shit you guys are into will always serve you very well. seriously.

[kel]

Teezee, thought you might enjoy this - Hubert Rigal's TZ collection

231789

but wait, its not just TZ's in his collection

231790

[wobbly]

I have just got an email from Frits Overmars, someone told him I had said that a few of the things he and Jan were saying was not right or misleading in some way.
He has offered to "tell me everything" so of course I asked for the very latest Aprilia pipe designs for 125 and 250 - he said yes of course, if I proved that the Sim worked as well as I said it did..
No problem there at all, so WooHooo, now I have a direct line into the real factory info.
Cant wait, and ultimately you guys will benefit in the engines we build.

[kel]

I have just got an email from Frits Overmars, someone told him I had said that a few of the things he and Jan were saying was not right or misleading in some way.
He has offered to "tell me everything" so of course I asked for the very latest Aprilia pipe designs for 125 and 250 - he said yes of course, if I proved that the Sim worked as well as I said it did..
No problem there at all, so WooHooo, now I have a direct line into the real factory info.
Cant wait, and ultimately you guys will benefit in the engines we build.

Nah your having us on???
No one is challenging Frits and Jans statements on their forum, we graciously listen.

Frits certainly seems like the type of guy that would happily share info to advance the understanding of two strokes of all that are prepared to listen, perhaps we could encourage him to directly post here?

[TZ350]

The boys have done a good job dialing it in.

But how close can you get without actually getting there.

231815

The red line is my old cylinder and the blue the side Ex port one.

To get as much blow down as possible I made the transfer time area a bit short for 12.500rpm with the transfers opening 116 ATDC .

I am going to try raising them to 114 ATDC and see what happens, hopefully a little more low end and another top end hp.

[kel]

That is so close to the magic number :niceone:
Any chance we can see an over lay with speedpros dyno graph.

[TZ350]

Any chance we can see an over lay with speedpros dyno graph.

Yes, but only if he says its ok........

[Buckets4Me]

TeeZee

I assure you faster buckets have been built than yours 20 years ago.

You are actually relatively new to buckets, and you often present items you have simply googled and read,and not actuall experience.


. . . . . . :facepalm:

[richban]

But how close can you get without actually getting there.

Shit you should just blow some cold air into the carb and you will make the 30.

[Bren_chch]

I got a 29hp engine on triple-r-superbike dyno, the clutch was slipping bad and it was sucking in gearbox oil so i am sure there is a bit more power, i was running a 33mm vmx carb but am going to try a 28mm pwk carb, i have fixed the clutch with a new kit and added stronger springs, also fixed the oil issue with new seals and more GOO around the rotary disk cover. Its running a cr125 ignition which i want to replace with a zeetronic so i can make use of the powervalve and sort a good tune out.

On its first outing it shagged the original clutch kit and then started drinking the gearbox oil but it was still reaching just over 170kph at ruapuna, there were more power available but i ran out of smaller back sprockets.

I had some good help from F5Dave and Peter Steadman.

its in a rs125 chassis

Oh the pipe is a modified tz250 swarzzzz... swerz......... na swarzbrook?? shit cant remember pipe. seems to work pretty awesome, strong power everywhere.

I would actually like to send all my spec/info to wobbly and see if he has any ideas on what else i could do to make it better.

Some pics below.

[Bren_chch]

the bike.... and engine finished

[Buckets4Me]

I got a 29hp engine on triple-r-superbike dyno, the clutch was slipping bad

:yes::drinkup::woohoo: well so much for beating you guys down there with shear POWER

:facepalm: and we luck out on the good looks as well

but isn't that a Kwonda BR100R :)


I LIKE IT A LOT

[k14]

the bike.... and engine finished
I thought you told me that you bored it out to 125cc :innocent:

[Yow Ling]

I thought you told me that you bored it out to 125cc :innocent:

that was the joe1 motor

[Bren_chch]

that was the joe1 motor

HA! the amount of people that used to ask if that motor in that horrible old joe1 frame had been checked for being within the rules!

What are they going to say when the new motor/bike gets totally sorted.

Take that SKINNY kids! :scooter: revenge of that fat men!

[TZ350]

the bike.... and engine finished

Cri..st I was feeling cocky untill I saw your bike ........... :facepalm:

[all4A50s]

.

Check the size of the rotary valve ports

230305

My GP will have an inlet port that looks like this soon ....... :lol:

And I have an idea how I could make a variable port where the closing point can be changed, much like a blade power valve.

I didn't know an engine could just consist of carbs and exhaust. Do the carb restrictions still apply?:weird::doctor::not:

[TZ350]

Do the carb restrictions still apply?

125's are still restricted to 24, some doubt about the legality of oversized carbes sleeved back to 24.

But I have other carbs, pumper and plug/slide that meet the spec by any definition, that I can run if needs be. One flows more than the unit I am using now.

[Henk]

I didn't know an engine could just consist of carbs and exhaust. Do the carb restrictions still apply?:weird::doctor::not:

No carb or cooling restrictions on 100s

[TZ350]

I got a 29hp engine on triple-r-superbike dyno, the clutch was slipping bad and it was sucking in gearbox oil so i am sure there is a bit more power, i was running a 33mm vmx carb but am going to try a 28mm pwk carb, i have fixed the clutch with a new kit and added stronger springs, also fixed the oil issue with new seals and more GOO around the rotary disk cover. Its running a cr125 ignition which i want to replace with a zeetronic so i can make use of the powervalve and sort a good tune out.

I had a look at the www.FXR150.co.nz (http://www.fxr150.co.nz/) site, and see there are one or two more very fast 2-strokers in the pipe line down south and a bunch of very interesting FXR's.

[F5 Dave]

Cri..st I was feeling cocky untill I saw your bike ........... :facepalm:
Of more concern is Bren is a pretty shit hot rider into the package. If Nigel can get himself fit & willing to ride 100% & Bren can get his sorry arse up to Taupo it would be a race worth watching.

[F5 Dave]

I got a 29hp engine on triple-r-superbike dyno, the clutch was slipping bad and it was sucking in gearbox oil so i am sure there is a bit more power, i was running a 33mm vmx carb but am going to try a 28mm pwk carb,. . .
Betterer & betterer! I'd be searching around for other carbs to try, space is an issue on the old Joe, but with some case shaving & moving the inlet a bit it'd be fun to try a 34 or 35mm. Wonder if some of those short bodied MX125 carbs may fit in & work well. PWK35 is quite a size up from the 28. FCR conversion are too downdraft. . .hmm.

[Bren_chch]

cheers Dave - ahhhh so i should be going biggerer!! Mike has as cr125 carb laying in some dust, i think its 35mm or even bigger?? , maybe i can borrow that for testing! actually i got a rg400 carb too, what you rekon???

oh kinda stealing this therad a little. sorry ESE

yippeeee

[richban]

cheers Dave - ahhhh so i should be going biggerer!! Mike has as cr125 carb laying in some dust, i think its 35mm or even bigger?? , maybe i can borrow that for testing! actually i got a rg400 carb too, what you rekon???

oh kinda stealing this therad a little. sorry ESE

yippeeee

Been trying to find the flow figures for the 32pwk on the FXR. I think it was close to 124 cfm 32hp ish. So a PWK33 might be a good option to try. The difference between the 30 and 32 on the dyno was 1.4 hp at the top nothing in the middle. The head will flow 32.5hp. Note sure if that helps but them pwks flow well. Old TM 28 Mikuni 110cfm max potential 27.5hp no good to you.

[Buckets4Me]

oh kinda stealing this therad a little. sorry ESE

yippeeee

Steel the thread all you like
as long as there are pictures and stories to go with it
the tread is all about making a fast 2 smoker for the TRRS :scooter:

and sharing idears around

[F5 Dave]

I certainly reckon its worth trying, assuming your inlet is ok for it.

[bucketracer]

Flow tested some carbs today. Thomas made up a manometer, which proved to be very effective at measuring flow through the carburetors.

Thomas made the manometer from some clear tube an old tape measure and some din rail and filled it with anti freeze and it worked a treat. He's a clever fellow is Thomas.


231890 231889

There are a number of posts here about Thomas and TeeZee's method of measuring which carbs and modifications flowed better.

[bucketracer]

231898

Putting TeeZee’s 1978 Suzuki GP125 29.9 rwhp (33hp at the crank) into perspective.

231895

Suzuki RT63 1963
Engine type: Air-cooled 123.70 cc twin cylinder rotary valve 2-stroke. 25.5 ps/ 12.000 rpm.
Bore x stroke: 43.0 x 42.6 mm
Carburetor type: M24
Compression ratio: 8.8:1
Top speed: 184 kph
Clutch type: Dry multiple plates
Transmission: 8 gears
Tyres: 2.50-18 / 2.50-18
Brake type (front): 2 drums, 1 cam
Brake type (rear): 1 drum, 1 cam

231896 231893 231894

Honda MT125R Hondas 1978 over the counter 125 Racer. The tuned versions were 23-25 rwhp (26-28hp at the crank)

231892

29.9 rwhp from a tuned learner bike dating from the late 70’s is not all that bad.

And better than the Honda factory was doing with their own 125 aircooled racer from the same period or the Suzuki factory GP aircooled racer from the period of factory Grand Pix competition in the 60's.

[jasonu]

the bike.... And engine finished

i like it!!!

[kel]

I got a 29hp engine on triple-r-superbike dyno,
I would actually like to send all my spec/info to wobbly and see if he has any ideas on what else i could do to make it better.

Holly crap :gob: Assuming your motor is peaking at 13000rpm that gives you a BMEP of approximately 11 bar, that is some phenomenal backyard engineering that you should be extremely proud of :2thumbsup

[Bren_chch]

yow ling had a carb or two laying around so i borrowed them, will tell him later! :innocent:

I thnk i have lucked on something again, not sure what but i need to go back and see what i changed when i rebuilt the motor, or maybe its just the clutch is actually working 100%, engine seems a lot stronger, but i did widen the inlet and and added a bit more advance on the timing, engine seems to pull harder... that is when i dont bog it down off the start.

uploading a little driveway test to youtube now, will add to thread after dinner.

231949231950

[Bren_chch]

Holly crap :gob: Assuming your motor is peaking at 13000rpm that gives you a BMEP of approximately 11 bar, that is some phenomenal backyard engineering that you should be extremely proud of :2thumbsup

i've got no idea what your on about... :facepalm:

12000rpm according to my digital counter... cheers ears!

[speedpro]

Been chatting to TZ about a TS/RGV hybrid and finally found a few shots of an older effort. Shame I didn't know a bit more about tuning back then.

[Bren_chch]

Been chatting to TZ about a TS/RGV hybrid and finally found a few shots of an older effort. Shame I didn't know a bit more about tuning back then.

ok thats interesting looking!!! :yes: what happened 2 it?

Here is my short driveway test:


http://www.youtube.com/watch?v=gPPq69799XI

[gav]

OK, Two things, Bren, was it 32hp you saw on Reds dyno at your last go?
And how is it that here at the nationals, 2 150cc four stroke bucket bikes top the 150SS qualifying charts?
http://www.mylaps.com/results/showrun.jsp?id=1782157

[Bren_chch]

OK, Two things, Bren, was it 32hp you saw on Reds dyno at your last go?
And how is it that here at the nationals, 2 150cc four stroke bucket bikes top the 150SS qualifying charts?
http://www.mylaps.com/results/showrun.jsp?id=1782157

i didnt want to make claim until his printer is working! :woohoo:

those cbr's were honking it! they both got all the toys in them and both ridden by 60kg very fast kids! :scooter: poor rg150's beaten by 2 buckets! haha

[gav]

Apparently they are still considered a "Streetstock" :gob: :innocent:

[Yow Ling]

Been chatting to TZ about a TS/RGV hybrid and finally found a few shots of an older effort. Shame I didn't know a bit more about tuning back then.
Wow 17 years ago, these days there are better choices for bottom ends for rgv barrels
Pretty flash job ! Where is it now ?

[TZ350]

i didnt want to make claim until his printer is working! :woohoo:

Great drive way video......... that wheel stand, very impressive... http://www.youtube.com/watch?v=gPPq69799XI

Take a photo of the dyno screen, its what we do, you don't want to be beaten to be the first claiming 30hp just because a printers not working.

I hope to be able to tickle mine up to 30+hp next week.

[TZ350]

Been chatting to TZ about a TS/RGV hybrid and finally found a few shots of an older effort. Shame I didn't know a bit more about tuning back then.

Thanks for the photos, I have been a bit preoccupied finishing the final work on my aircooled 125. Being so close to 30 I want to see if I can get it across the line before starting on the Wobbly RGV/TF100 engine.

[TZ350]

That is so close to the magic number :niceone:
Any chance we can see an over lay with speedpros dyno graph.

232004

Red line Speedpros, Wobbly designed MB100 and pipe, Blue, TeeZees 125 air cooled.

I wasn't expecting the 100 to be phater than the 125.

[TZ350]

Buckets original video clip showing some air/fuel mass appearing in the carbs bellmouth as the engine gets up onto the pipe.

For wet air/fuel fog to be in the bell mouth at peak torqe the air would have had to pass the jet at least twice and for it to be sucked back in the air would have to pass the main jet for a third time. In this clip its making 27+ rwhp so there is probably nothing much wrong with the old Suzuki GP125's state of tune.

If there is another explination I would be interested in hearing it.

<iframe title="YouTube video player" src="http://www.youtube.com/embed/KcNfci9OruU" allowfullscreen="" width="480" frameborder="0" height="390"></iframe>

In the video clip you can see the fuel line get air pockets in it.

So adding a breather to the fuel filter I have a nifty header tank for the carb and cured that problem.

232005

I also had another problem with carburation.

Which I think is caused by wind blowing across the exposed bell mouth.

So I put a rubber wind break on the bell mouth and this seems to have cured it.

[RMS eng]

Been chatting to TZ about a TS/RGV hybrid and finally found a few shots of an older effort. Shame I didn't know a bit more about tuning back then.
Hi Mike ,thats a nice motor,looks like it would make an easy 25HP all day long,and maybe more now,jasons last KERG100 was made over 3 weeks and made 25.1HP with that old 80s TZ500 pipe.if you still have that RGV TS,you should give it another go.Chris

[jasonu]

I was more thinking of comparing dynos. They are not all created equal.


[QUOTE=Buckets4Me;1129982259]that would be telling indead
and if your bike is ever up this way I'm sure they would love to put it on the dyno and see what the difference realy is

I'm sure there would be a few interested people out there :corn::woohoo::drinkup:

I would really like to see that comparo.
When my bike is back on wheels I would like to run it on TZ's dyno. I have the original dyno sheets showing 25hp from a Dynojet 100 so a direct comparison is possible.

[TZ350]

Hey all...man it was DAMN HOT today.......:shit:
Anyways....here are a few pics.... http://gallery.me.com/speedshotz/100245 (http://gallery.me.com/speedshotz/100245)
Enjoy!

Great day at Mt Welly today, hot, but good fast racing.

232086 232084 232085

A couple of wins and many placings for the 2-Strokers in A grade, havent seen that for a while.

[Yow Ling]

Ive been dabbling with this engine for sometime now, when TZ350 started his RGV project we got together and started working with Wobbly to acheive a reliable and fast package. Some things are different between our camps, cohice of bottom end being the main difference. Ive gone with a RG125 its similar to an rg150 but not the same , I dont think they were imported to NZ but some electric bike guy sold it to me as he despised all things petrol.

TZ has posted pictures of my sleeve which is a bit of a compromise but will do in the meantime as we have some new ideas in that area.

The transfers require some changes , i was always loathed to touch them as i didnt have the right tools , someone lent me a 90° grinder but was really akward to use. I ended up getting some dentists drills so that will give me heaps of room to move round now.

The RS frame has a cross beam which the shock mounts onto , unfortunatly this is where the RG carb wants to go so i have found a different rubber and a Kehin carb that work together without having to modify the frame.

The engine mounts are a bit different between the rs and rg so to keep the chain line the same i am relocating the engine mounts on the frame , i looked at milling the mount on the engine thinner but would have been inside the crankase pretty quickly, still quite alot to do, but ill try and work on it most days for a few weeks to try and knock a hole in the project

got lucky RS125 sprockets fit so can run skinny chain no problem

[ac3_snow]

I get the slight feeling you may be a rotary valve fan TZ? Spotted a pic of these outboard reed valves and was amazed, I forget bikes aren't the only things using these engines, and that some of the other applications are on a much larger scale than the tiny things we are playing with.

Will you use an external reed block on your new RGV/TF engine?
232095

[F5 Dave]

Yeah that's the same type of reedblocks I'm using on the MB, but I'll have to use at least two braces of them.:blink:[Tui add]

Funny talking about R/A grinders. I was just thinking last night that I wish Dremel had made a mini RA flexidrive doofah. Well I went to replace my Dremel yesterday (I have a large Bosch grinder & two size air grinders which are nice, but sometimes for a quick job the Dremel is easy), anyway my old one is rattley after 20 years of hard work, so I buy a new 400 & notice they have a RA tool for 50 note.

Hmm, pretty big, oh & then the bits have to go in. So I'm holding it wondering if I could strip it down & spot weld a bit right close to the bevel part. Ahh sounds like a drama, must go see my mate with the dentist tool & see if I can persuade him to sell it now. Problem with the dentist tool is they have tiny bits & no torque. Great for correcting corners and defects, but not much else.

[TZ350]

Rick52

232122

Rick52 rode the wheels of his new bike and won or placed all day in "A" grade.

232124

When the bike was run up on the dyno it was found to have 18-19 rwhp.

232123

Comparison of Rick52's 18-19 rwhp with a Team ESE bike.

Sunday showed how talented Rick realy is and if he ever builds up that GP125 engine he has in the ESE style and gets 27+ rwhp he will be very dangerous and the 4-Strokes could prety much kiss it goodby at Mt welly.

[kel]

Sunday showed how talented Rick realy is and if he ever builds up that GP125 engine he has in the ESE style and gets 27+ rwhp he will be very dangerous.

What was evident from the sidelines on Sunday was how much quicker Rick was entering the corners, every corner! :sick:

[F5 Dave]

Rick52

When the bike was run up on the dyno it was found to have 18-19 rwhp.
. . . .
. . . peaking at 8700. so not a rev monster then:blink:. one might hazard a guess that its farmbike origins are still somewhat to the fore.

'cmon Chris (RMS) run a riffler up there.

[Moooools]

Fantastic work team ESE. Love watching the development.
Time to (be the second to) crack that 30hp mark!

[TZ350]

Time to (be the second to) crack that 30hp mark!

I am hoping to be the first, to post a dyno graph of 30+ rwhp from a bucket.......... :D

[TZ350]

232140

After 40+ dyno pulls at near 30hp the glue blocking the oiler holes is still there inside the piston..

[TZ350]

Tried one of Chambers pipes that he designed using Blairs formulas and it made 29 rwhp so not bad for a pipe design from a spread sheet. The Spread Sheet can be downloaded from page 200, post 2988.

The plan is to raise the transfers from opening 116 ATDC to 114 for a litte more Transfer Time-Area.

232143

The first step is to find 114 ATDC with a degree wheel.

232142

Then use Marking Blue and a Scriber to set the new Transfer Port height.

232144

Ports marked out. The cylinder has garks from my porting work and had done a turn on some road bike before being purchased on Trademe and it still makes good power, will rebore it when the experimenting is all done.

232141

Its a gamble rasing the Transfers as that will reduce the Blow Down Time Area. But I am betting there is a little blow down to spare and its the short Transfer Time Area thats holding it back and a little more will phaten up the lower part of the blue lines Torque Curve and hopfully crack the majic 30 too.

[Rick 52]

Rick52 rode the wheels of his new bike and won or placed all day in "A" grade.


Sunday showed how talented Rick realy is and if he ever builds up that GP125 engine he has in the ESE style and gets 27+ rwhp he will be very dangerous and the 4-Strokes could prety much kiss it goodby at Mt welly.[/QUOTE]

Cheers fellas your making me blush :facepalm: The new bike is 30kg lighter and has more power much better brakes and handles like a dream !If I didn't get quicker with this bike I should be just watching the racing...I need to ride this bike better before getting more power I think ..Better ignition from a Cr85 next and a engine strip down re-build ...

[richban]

The new bike is 30kg lighter and has more power much better brakes and handles like a dream !If I didn't get quicker with this bike I should be just watching the racing...I need to ride this bike better before getting more power I think ..Better ignition from a Cr85 next and a engine strip down re-build ...

Man after our battles at Taupo I was thinking it had more power than that. When you were coming out of the corners there was no way past. It just took off.

Thats it I am officially on a diet bike to.

Scuse me while I vomit.

[speedpro]

[QUOTE=TZ350;1129985663]The plan is to raise the transfers from opening 116 ATDC to 114 for a litte more Transfer Time-Area.

Its a gamble rasing the Transfers as that will reduce the Blow Down Time Area. /QUOTE]

There's enough metal there to widen the main transfer ports toward the exhaust port - more time/area but same blowdown

[koba]

I get the slight feeling you may be a rotary valve fan TZ? Spotted a pic of these outboard reed valves and was amazed, I forget bikes aren't the only things using these engines, and that some of the other applications are on a much larger scale than the tiny things we are playing with.

Will you use an external reed block on your new RGV/TF engine?
232095

Cool pic, got me thinking of this one...

Thats some serious reed area!

[TZ350]

There's enough metal there to widen the main transfer ports toward the exhaust port - more time/area but same blowdown

Good tip, I will give that a go first, also I will elongate the Ex side port tracts like you suggested before, too.

[TZ350]

Ive been dabbling with this engine for sometime now, when TZ350 started his RGV project we got together and started working with Wobbly to acheive a reliable and fast package. Some things are different between our camps, cohice of bottom end being the main difference. Ive gone with a RG125 its similar to an rg150 but not the same , I dont think they were imported to NZ but some electric bike guy sold it to me as he despised all things petrol.

I would be a starter for a RG125 engine, any condition, if I could get one, so if someone has one they would sell please PM me.

[TZ350]

Shit you should just blow some cold air into the carb and you will make the 30.

Got me thinking..................

232209

How about this baby.

A small turbo intercooler with a fine ice water spray over the fins, just enough to keep the fins wet. The latent heat of evaporation of the water would cool the air passing through the intercooler and going to the carb.

Another thing I could do is have the inlet air drawn from a high pressure area on the front of the top fairing just like a RS does for its air box.

[Kickaha]

A small turbo intercooler with a fine ice water spray over the fins, just enough to keep the fins wet. The latent heat of evaporation of the water would cool the air passing through the intercooler and going to the carb.

I wouldn't have thought you'd be allowed anything which sprays fluid about externally regardless of how little

[kel]

Hello all, probably not the right thread for this but as I started out using this software to try and develop the 2 stroke thought Id post here ...
Ive been playing with engine performance and evaluation software called lesoft. Its adaptable to both 2 and 4 strokes but while Im having trouble sorting my model for the 2stroke the 4 stroke setup is fairly straight forward, with all my FXR data entered (64mm piston, 12:1 comp, etc) its suggesting the standard cam timing can be tweeked to give it a bit more go. Have attached the simulators output graph for standard timing, inlet change only and optimised inlet and exhaust timing, Ill update with a dyno run vs the simulators prediction in the near future. In the mean time if anyone else wants to give this software a go its available free from http://www.lotuscars.com/engineering/en/engineering-software-downloads

232240

[TZ350]

I wouldn't have thought you'd be allowed anything which sprays fluid about externally regardless of how little

Yes, does seem doubtful, as an alternative the inter cooler could be submersed in a sealed container of ice water, and change the warmed ice water between races.

Instead of having the drag from air blowing through a radiator, racing aircraft have submersed the radiator in a tank of water and let the latent heat of evaporation cool the radiator as the water boils off during a race.

[TZ350]

I measured up the difference between the transfer height and exhaust of the 27 and 29 hp cylinders today and it is only 0.5mm.

232290 232291

That hardly seems enough to make the difference seen in the two graphs.

232292

The 27 hp cylinder with the good torque curve had been carefully setup using the bucket and vacuum cleaner motor flow bench and the transfer streams carefully matched.

232288 232287

I am now suspecting that more torque could be gained from flow testing the 29hp cylinder and matching the transfers than by just rasing them.

232289

I have read (Jennings I think) that max hp is not affected so much by mismatched transfers but the torque curve is, and with mismatched transfers the power delivery becomes peaky.

[TZ350]

232294

The Transfers on my 29.9 rwhp Suzuki GP125, decent dividers in the transfer tract might help too.

232295

In the last few runs when I was getting a consistant high 29's the exhaust had this hole in it.

Hard to know if this helped or held me back from cracking 30.

[Yow Ling]

I wouldn't have thought you'd be allowed anything which sprays fluid about externally regardless of how little

is there a specific rule you are refering to?

[Kickaha]

is there a specific rule you are referring to?

No, but I haven't bothered checking whether there is anything that would allow you to spray fluids over the outside of your bike

I heard of a better idea which would involve building a container with the intake running through it and LPG circulating around the outside, apparently when it was tried on a Diesel Terrano it dropped the intake temp close to 40 degrees

It would also allow much more spectacular explosions when it was crashed wore through and ignited

[TZ350]

......... is anything that would allow you ........

"rules that allow you" novel way of looking at rules, I thought it was anything goes unless there was a rule disallowing it.


I heard of a better idea which would involve building a container with the intake running through it and LPG circulating around the outside, apparently when it was tried on a Diesel Terrano it dropped the intake temp close to 40 degrees

It would also allow much more spectacular explosions when it was crashed wore through and ignited

The liquid gas turning to vapor cools the inlet, that would work.

Actually you could use a water/air intercooler and run the LPG liquid to gas phase through the water side.

232307

Latent heat of evaporation with explosions and fire, I am liking this idea more and more.............

[Henk]

If you do the LPG thing please warn me so I can go and hide behind something very big the first time you try it.

[Kickaha]

Latent heat of evaporation with explosions and fire, I am liking this idea more and more.............

Make sure you are videoing the meeting you try it at

[TZ350]

232312 232311 232310

Chambers is experimenting with making cylinder sleeves.

When he gets his tecnique right and the shapes he wants he will make an alloy one.

[wobbly]

"I measured up the difference between the transfer height and exhaust of the 27 and 29 hp cylinders today and it is only 0.5mm".


That difference is HUGE in relationship to the transfer STA, and thus its effect on the Blowdown.
For example a 0.5mm change would raise a port from say 115.8ATDC to 114.5ATDC in a 50mm stroke engine.
That is a duration change of 131 Vs 128.4 ie 2.6* - night and day, when you consider that in a KT100 kart engine changing the transfers by 0.1mm = a difference of 1.5 Hp in 18.

When you are at the outer limits of what a porting setup can achieve, then tiny differences make a big effect.

[TZ350]

"I measured up the difference between the transfer height and exhaust of the 27 and 29 hp cylinders today and it is only 0.5mm".

That difference is HUGE in relationship to the transfer STA, and thus its effect on the Blowdown.

tiny differences make a big effect.

Thats the encouragement I need........... will have a go at it tonight.

[ac3_snow]

Thats the encouragement I need........... will have a go at it tonight.

If you don't mind me asking what tool do you use to change the transfer port heights? I'v noted your use of the long shaft die grind bits (very helpful!) and of course the dremel with flex shaft is magic for final port shape etc but the transfer ports seem pretty hard to get at. I don't know any dentists, is there another tool/method?

[TZ350]

If you don't mind me asking what tool do you use to change the transfer port heights? I'v noted your use of the long shaft die grind bits (very helpful!) and of course the dremel with flex shaft is magic for final port shape etc but the transfer ports seem pretty hard to get at. I don't know any dentists, is there another tool/method?

Yes, I find the transfers hard to get at too. I use a battery drill and those long shaft die grinder bits and a dremmel with small ball stones.

Its not easy to make a smooth angled port roof but with care you can make a reasionable job.

232368 232369 232370

The pro porters will undoubtably have better gear and make a better job, but we work with what we have.

Just have a go, this is Buckets and we are allowed to just, give it a try and learn as we go along.

Below is a post showing how we hogged the ports out, got them wrong and then filled them with Devcon to get a smooth shape and the timing we wanted, the devcon stayed in the transfer ports ok.

232371


Rebored the cylinder and chamfered the ports before gluing up the transfer porting mistakes, actually over cutting the transfers and then gluing them back up turns out to be a real easy way to get a smooth symmetrical port.http://www.kiwibiker.co.nz/forums/images/misc/pencil.png

[TZ350]

Page 240

Links and Interesting Quotes from the last 10 pages, other link lists can found on the decade pages starting with Page 80.

A handy (and cheap $16 USD) Porting Calculator from:- http://www.porting-programs.com/ is based on Blairs and Jennings work.


Some more RSA125 development info from Jan Thiel
"No pressure transducers were ever used in our engine development.
And time/aerea was never calculated.
The port timings remained practically the same during 15 years!
What we did was trying different angles and radiuses, mainly on
the transfer ducts. I think we tried 40 different types of transfer ducts
that did not chanche the time/aerea. It was all about in which direction
the charge entered the cilinder and how the tranfer streams influenced upon
each other! Also about 200 different exhaust pipes were tried. After 2004
nothing much was changed but we improved with different power jet and
ignition mapping. It seemed nearly impossible to improve the transfer ducts
any more. The exhaust ducts were CNC machined, using different programs,
mainly to reduce exhaust duct volume. Also about 100 head designs were tried"

And Kel gave me this link to a very interesting book. www.prme.nl/download/engine-1.pdf (http://www.prme.nl/download/engine-1.pdf)


Yes, dead right the STA numbers havnt changed at all since the theoretical work was published out of Queens in Belfast by Blair etal.

But Thiels comments about the ports is a bit misleading really.
Aprilia completely changed the whole layout from previous 3 port geometry.

Instead of the main port being right at the 72% limit, they reduced this to 68% and dropped the main transfers below the rest.This enabled the large secondary Ex ports to be added, plus gave room to pull all the transfers around and create more area with less timing.

What this lead the way with,is being shown all the time now in the sims I run, that the Ex STA means jack shit, Blow Down STA is Everything.

232386 232388


"I measured up the difference between the transfer height and exhaust of the 27 and 29 hp cylinders today and it is only 0.5mm" (TeeZee).

That difference is HUGE in relationship to the transfer STA, and thus its effect on the Blowdown.
For example a 0.5mm change would raise a port from say 115.8ATDC to 114.5ATDC in a 50mm stroke engine.

That is a duration change of 131 Vs 128.4 ie 2.6* - night and day, when you consider that in a KT100 kart engine changing the transfers by 0.1mm = a difference of 1.5 Hp in 18.

When you are at the outer limits of what a porting setup can achieve, then tiny differences make a big effect.


Ive been playing with engine performance and evaluation software called lesoft. Its adaptable to both 2 and 4 strokes ……. if anyone else wants to give this software a go its available free from http://www.lotuscars.com/engineering/en/engineering-software-downloads 232240


Get Kev to fill in the inputs needed for my header design program I gave him a while ago, easy to make a screamer if the FXR hardware is able to be "fixed" properly.

232387


You have to print the attachment and fill it in, scan and send to me.

www.FXR150.co.nz (http://www.FXR150.co.nz) there are one or two more very fast 2-strokers in the pipe line.

Brens driveway test: http://www.youtube.com/watch?v=gPPq69799XI

From Koba good links of old lathes if you like such things http://www.lathes.co.uk/

Carbon Fibre Pistons http://www.techbriefs.com/component/content/article/2258


Dont be a big girls blouse - the FXR with 48.8 stroke should be at 13000 all day, its well under 4500 ft/min and the pressure fed big ends are way less prone to cage skidding causing failure.


No one has managed to get "ringless" pistons to work in a normal sized bore on petrol, but a company I work for has a patent on a trapped piston ring that allows a T port with no bridge. See http://www.wipo.int/pctdb/en/wo.jsp?WO=2005121608


Posted before but still interesting. http://www.madsci.org/posts/archives/2000-04/955373778.Ph.r.html

The normal ignition takes care of the ionisation channel; then as soon as the current starts to flow, the Emot-set sends a big extra current through this channel. It looks like this: http://www.youtube.com/watch?v=7BfQuxyWN90


Here is a test I did ages ago when I was pissed at having to pay $140 for shorty RS125 plugs - and more for the cap..
The test shows 4 different 10.5 plugs in a 3 time Nationals winning 125 kart engine,and each curve is a 3 run average.
Red is B105EGV .
Lime is Denso TAE01-32 ( later Honda replacement for the NGK shorty)
Brown is NGK R6252K - 10.5 ( kawasaki 125 special)
Orange is NGK R6120A - 10.5 Shorty Iridium as sold by Honda.
The trick plug is worth a couple of Hp , this can be bought now as a normal length plug with the Iridium center and Platinum Earth as NGK R7376 for about 1/2 the price, and uses a normal plug cap.

232390


I spent months learning how to do real nice blown pipes when I worked for JL in England and we were contracted by ZipKart to do some special pipes for the British Superkart GP at Silverstone.No matter what I did I couldnt get the same power as the hand made cone pipes.
The problem is that no matter how you do it, the changes in area are "smeared" together, especially around the mid section.
Finally we decided to make the curved header part only as a blown section, as this is very time consuming when welding alot of sections together.
This combination actually made 1.5 Hp per pipe more ( only the front pipe is curved on a Superkart).
If you look at Honda factory bikes the pipes are pressed in 2 halves and have very sharp "corners" where the angles change.
And the last GP pipes I had anything to do with - the 250 KTM, were made this way.

232391


The powerjet carb is controlled by the Ignitech with a combination of throttle position and rpm in a "truth table".
In general the solenoid is activated with 12V ( no fuel flowing) below 4000 rpm and 75% throttle on the TPS.

Above 75% and around 12400 rpm it is activated again to lean off the fuel curve over the top of the pipe.
Looks like you will be able to reverse the fuel exit, blocking off the hole on the throttle bore side, and take off fuel from the outside bung, thru a needle jet and into the top of the venturi next to the slide.

232389


Well funilly enough that (concave dome) Kawasaki piston gave rise to the idea of a toroid shape. I think they were trying to get the plug closer to the centre of the combustion area, but of course it shagged the squish action as well as the transfer flow regime. The toroid shape does everything right and there is no reason to use anything else.

There are over 1,200 images on this thread, to find the interesting ones use “Thread Tools”, then “View Images” near the top of this page. You can view the images 70 at a time from the beginning. It’s a quick way to find some of the interesting posts too.

[koba]

Yes, I find the transfers hard to get at too. I use a battery drill and those long shaft die grinder bits and a dremmel with small ball stones.

Its not easy to make a smoth angled port roof but with care you can make a reasionable job.

232368 232369 232370

The pro porters will undoubtably have better gear and make a better job, but we work with what we have.

Just have a go, this is Buckets and we are allowed to just, give it a try and learn as we go along.

Here is a post showing how we hogged the ports out, got them wrong and then filled them with Devcon to get a smooth shape and the timing we wanted, the devcon stayed in the transfer ports ok.

232371

Have I mentioned I have lust eyes for old lathes?

Here is a pic of the one I've used most, It belongs to the old mans mate and is pretty old. It has the old flat leather belts and some of the tooling used on it he bought back from the second world war.

Edit: good link if you like such things http://www.lathes.co.uk/

[Yow Ling]

Have I mentioned I have lust eyes for old lathes?

Here is a pic of the one I've used most, It belongs to the old mans mate and is pretty old. It has the old flat leather belts and some of the tooling used on it he bought back from the second world war.

Edit: good link if you like such things http://www.lathes.co.uk/

in the 70's there was a tv show called Logans run, was it inspired by this lathe ?
the lathes site is the last word if you are reasearching old machinery, doesnt havre much east european stuff though

[koba]

in the 70's there was a tv show called Logans run, was it inspired by this lathe ?
the lathes site is the last word if you are reasearching old machinery, doesnt havre much east european stuff though

I'm a bit young to know... younger than both!

Yeah, there is definatley plenty more stuff from around the world.

[wobbly]

Just one thing to add here re the screamer 100 engines we are looking at building.
To make the sort of power we are looking for, we have to use around 200* of Exhaust timing.
This works with a TL of around 800mm to give power up to the 14000 mark.
But this timing and pipe length is a resonance mismatch.
For it to work, and rev that high, we HAVE to use a solenoid powerjet, to get heat into the pipe ( along with pulling out timing to near TDC ).
This combination will not run above the power peak on a normal carb.
To get power and revs with a "normal" carb requires a timing of around 83* ATDC and a tuned length of around 830, but this seriously limits the blowdown STA and thus the power that can be achieved.

And I use a 182MC right angle head ,available from C C Speciality in the States, for porting the transfers - but I hate it with a passion.

[k14]

Just one thing to add here re the screamer 100 engines we are looking at building.
To make the sort of power we are looking for, we have to use around 200* of Exhaust timing.
This works with a TL of around 800mm to give power up to the 14000 mark.
But this timing and pipe length is a resonance mismatch.
For it to work, and rev that high, we HAVE to use a solenoid powerjet, to get heat into the pipe ( along with pulling out timing to near TDC ).
This combination will not run above the power peak on a normal carb.
To get power and revs with a "normal" carb requires a timing of around 83* ATDC and a tuned length of around 830, but this seriously limits the blowdown STA and thus the power that can be achieved.

And I use a 182MC right angle head ,available from C C Speciality in the States, for porting the transfers - but I hate it with a passion.
Glad you cleared that up, I was just going to bring that up... :blink:

[RMS eng]

Just one thing to add here re the screamer 100 engines we are looking at building.
To make the sort of power we are looking for, we have to use around 200* of Exhaust timing.
This works with a TL of around 800mm to give power up to the 14000 mark.
But this timing and pipe length is a resonance mismatch.
For it to work, and rev that high, we HAVE to use a solenoid powerjet, to get heat into the pipe ( along with pulling out timing to near TDC ).
This combination will not run above the power peak on a normal carb.
To get power and revs with a "normal" carb requires a timing of around 83* ATDC and a tuned length of around 830, but this seriously limits the blowdown STA and thus the power that can be achieved.

And I use a 182MC right angle head ,available from C C Speciality in the States, for porting the transfers - but I hate it with a passion.

200* and 14000 rpm will be hard work to get a fast lap time on kart track,

[wobbly]

Well here is a set of curves for a hot customer RS125in green, the other two curves are 200* and short pipe, what is called the A Kit spec..
One is with the PV working - the other locked up.
Note it makes over 40 Hp from 11500 to 14000 and peaks at 50.
This sort of fat spread doesnt even need a close ratio box, and if you tanslate this sort of performance to the 100cc with the PV working, it would make the MB100 of MIkes or NoMates RG100 look sick - and since when did Nomates ever get beaten at Mt Welly when he didnt bugger it.

[RMS eng]

Well here is a set of curves for a hot customer RS125in green, the other two curves are 200* and short pipe, what is called the A Kit spec..
One is with the PV working - the other locked up.
Note it makes over 40 Hp from 11500 to 14000 and peaks at 50.
This sort of fat spread doesnt even need a close ratio box, and if you tanslate this sort of performance to the 100cc with the PV working, it would make the MB100 of MIkes or NoMates RG100 look sick - and since when did Nomates ever get beaten at Mt Welly when he didnt bugger it.

NoMates is a good rider,but hasn't been to the track for a while,he may have to work for a win with one of the 21 hp derbi 80 s.have to keep an eye out for a RS100 A kit.

[Buckets4Me]

NoMates is a good rider,but hasn't been to the track for a while,he may have to work for a win with one of the 21 hp derbi 80 s.have to keep an eye out for a RS100 A kit.


wont take him long to knock a N D off the track :facepalm::shutup:
and we all know he will do it and what the outcome will be (oh wait thats why he hasn't been back for so long):facepalm:

[wobbly]

Nigel NoMates has a crushed vertebrae in his back, and had sent his cylinder away for plating on the cast iron, that is why he hasnt raced for a while.
But as I say ,the new engines having the same sort of spread as the A Kit RS125, but peak at say 33Hp, then that will give the lie to 200* and 14000 being hard to ride.

[jasonu]

since when did Nomates ever get beaten at Mt Welly when he didnt bugger it.

Or knock his competitors off...

[TZ350]

Raised transfers from 116 blue line to opening 114 ATDC red line.

232490

I was expecting to maybe lose something off the top because of the reduced blow down, and fatten the bottom end but this is the other way??????

Must have done something wrong....... :scratch:

232491

Fiddling with the ignition curve and jetting I can get a bit more out of the curve higher up but the bottom is still stubbinly weak.

It sure is easier to lose hp than gain it.

[TZ350]

Got it..........

232492

First ever dyno graph posted of a Bucket cracking 30rwhp

Air cooled, rotary valved 1978 Suzuki GP125 Engine on a DynoJet dyno.

[Yow Ling]

just a leeetle bit more, go on, you know you want to

[koba]

Got it..........

232492

First ever dyno graph posted of a Bucket cracking 30rwhp

Air cooled, rotary valved 1978 Suzuki GP125 Engine on a DynaJet dyno.

Congrats! <tenchar>

[richban]

Got it..........

First ever dyno graph posted of a Bucket cracking 30rwhp

Air cooled, rotary valved 1978 Suzuki GP125 Engine on a DynaJet dyno.



Good stuff you guys have put in the hard yards. I am having a beer in your honor. Now go ride the wheels off it.

[Rick 52]

Brilliant good work ,You must be very happy with that:gob:

[koba]

Good stuff you guys have put in the hard yards. I am having a beer in your honor. Now go ride the wheels off it.

Perhaps next time we all get together we can sit around after racing and drink piss and talk shit in celebration...

[Henk]

Perhaps next time we all get together we can sit around after racing and drink piss and talk shit in celebration...

What, In two weeks?
Hopefully ESE are coming down the line.

[koba]

What, In two weeks?
Hopefully ESE are coming down the line.

Hmm, even if they can't make it maybe we should have a few in honour of thier achivements...

[Henk]

Hmm, even if they can't make it maybe we should have a few in honour of thier achivements...

I think I could do that.

[speedpro]

The clutch is going to get hell keeping it at 30 on the track, eh.

Nitro is wonderful stuff. You just tip it in and Bob's your uncle, cough cough! :innocent:

[Bert]

Got it..........

232492

First ever dyno graph posted of a Bucket cracking 30rwhp

Air cooled, rotary valved 1978 Suzuki GP125 Engine on a DynaJet dyno.

Well Done Gentlemen.
18 months of hard work has paid off.
now it time to see a 100 pulling the same.

[TZ350]

...... now its time to see a 100 pulling the same.

I have a Wobbly water cooled 100cc engine in the pipe line.

And these are some pictures of Chambers planning a new sleeve for his air cooled 100.

[jasonu]

Got it..........

232492

First ever dyno graph posted of a Bucket cracking 30rwhp

Air cooled, rotary valved 1978 Suzuki GP125 Engine on a DynaJet dyno.

NICE JOB!!!
I look forward to seeing it on the track laying waste to the coal burners.

[TZ350]

I look forward to seeing it on the track laying waste to the coal burners.

Still a bit of work getting it to be drivable, when its finished it should be a fun ride :D but it will probably need a better rider than me to see all the coal burners off....... :scooter:

[kel]

Got it..........

First ever dyno graph posted of a Bucket cracking 30rwhp



:2thumbsup Good work mate :drinknsin

[koba]

it will probably need a better rider than me to see all the coal burners off....... :scooter:

I'm Available... :Pokey:

[TZ350]

232766

Thomas comes up with the goods again......... RSA ?

232769

Transfers

232768

Main Ex Port 66% of bore

232767

Old bridge oilers glued up, so now we know for sure that gluing the piston works, just like Thomas said it would.

[kel]

Thomas comes up with the goods again......... RSA ?


Looks like a Chinese knock off

[TZ350]

Some interesting tit bits from:- http://www.pit-lane.biz/t117p570-gp125-caracteristiques-aprilia-rsa

Jan Thiel
We did not flow the principal and secondary transfers separately.
In fact flowing the transfers makes little sense!
The important thing is more their direction and how
they influence upon each other.

Frits Overmars
The best place for a lambdasonde is in the fat part of the pipe where it least disturbs the flow, and in the top side so that it does not get fouled by oil.
If that is not possible, then put it so far away from the cylinder that there is a pipe volume of at least twice the cylinder volume between it and the cylinder. That way you can be sure that the lambdasonde will not be fouled by unburnt mixture.

I guess Jan is talking about Blow-Down here.

Jan Thiel
At high rpm there is some reverse flow, the transfer ducts becoming black, and even the
crankcase and carburetter bellmouth because of the entering burned gasses.
This happens because with raising rpm. the pre-exhaust flow becomes insufficient.
When rpm raises still more there is no more transfer flow and the engine stops completely.
So transfer flow depends completely from what is 'allowed' by the exhaust flow! We never used a lambda sonde.

Riley Will
The 125cc engine made 48 hp (sae) at the rear wheel. I have used my cylinder on the Rotax 129 engine where it made 50hp. Much of our technology has been derived from Aprilia. I believe I can make more with the reed valve engine by focusing development on the reedcage and inlet. However, it has been my experience that the mid range power of the disk valve engine is always superior. I have found over rev power of the reed valve engine to sometimes be eassier to achieve. In the past I would also produce more peak hp with the reed valve engine but the mid range maybe 7% less than the disk valve. Our 150cc engine when using Methanol has made 56hp and 24 ftlbs of torque. I love it for its simplicity. Our 250cc twin has made 104hp when using leaded fuel and Aprilia MW47 combustion chambers. I have also made tests on a 125cc disk valve engine with fuel injection. This made 10% more power everywhere than carburated!!! I want to spend more time in this area. At the moment we are fine tuning our 250cc twin engine for the 2011 superkart season. We have made crankcase, cylinder, and combustion chamber modifications in order to raise peak HP and over rev HP.

232829232826

Frits Overmars
The JBB engine. It is a lot lighter and more compact than a tandem twin.

232827232825232830

The JBB engine (created by Jean-Bertrand Bruneau who is a member of this forum), has two separate crankcases.
The crankshaft has a common big-end pin with a center disc which forms the separation. Hopefully the following pics will make it clear:

232828

Riley Will
Those are the carburators used when burning methanol. It is needed not for more air, but to have the ability to move enough methanol!!! When running with Methanol, you can see your fuel tank dropping on the straights!!!!

[wobbly]

The unsupported disc between the cylinders is also the type of crank design as used in the SwissAuto V4 - Gp engine, that ended up as the Pulse 500 as run by some of the guys from the BSL500 team..This is called a flying web crank, but has the pins opposite to give 180* firing in adjacent cylinders.

One thing to note in the pics of the cylinder held by Thomas - the real RSA does not have any taper at all at the top of the duct divider ( septum), the end of the divider just has a small radius on each side.
This is to reduce the area ratio between the duct entry and the port exit.
Edit, here is a better pic I have just got.

[F5 Dave]

Ahh, I'd never seen the twin inlet single disc arrangement, just assumed like a tandem, but it makes sense & is way compact. Nice.

Makes you think if they still raced 500s they'd be well over 200 at the wheel. [sigh]

[kel]

Now that Rob has put a link to pit-lane.biz (my almost secret place for all things techo), I'd encourage anyone who loves race bikes to check it out. Its a French site so you'll need to use something like google translator (which can be amusing) although Jan, Frits and others do post in english, those clever Europeans tend to speak more than one language which does help. There's all kinds of super cool technical info on most racing classes plus pictures of just about everything. Enjoy!

http://www.pit-lane.biz/

[speedpro]

Interesting that the webs in the JBB engine aren't full circle. I have to wonder about friction and crankcase compression and balance factors. I presume the crankpin has a spline machined into the centre that the centre plate sits on, I can't see it being pressed into place. Very cool engine.

[TZ350]

One thing to note in the pics of the cylinder held by Thomas - the real RSA does not have any taper at all at the top of the duct divider ( septum), the end of the divider just has a small radius on each side. This is to reduce the area ratio between the duct entry and the port exit.

Hi Wobbly, I have heard you mention that before, it used to be that the entrance to the transfer duct was just a little bigger than the port window and that seems sensible, to make it like a funnel.

So why do they make the duct entry the same or a little smaller than the transfer port window now? Is it to reduce the gas velocity out of the port?

[wobbly]

If you look at the old Rotax pic it has a duct entry to port ratio of about 1.4.
The base gasket dimensions are virtually identical to the late model cases.
The RSA/RSW has a ratio close to 1.2, so its still tapered down to the port exit but no where near as much.
If you look at the Delivery Ratio of a full on 2T engine, virtually all the volume that ends up in the cylinder, is actually sitting in the transfer ducts, NOT the case.
The smaller this volume is, the quicker it can be accelerated thru the duct into the cylinder.

[F5 Dave]

putting paid to Bell's (or was it Jennings?) comment that it was virtually impossible to make the transfer entry ducts too big. Always challenge the classical wisdom I suppose.

[TZ350]

Got my cases back today, they have been bored for the RGV cylinder.

232931

Cylinder fits Ok

232930

The position of the reed block.

232928

Speedpro told me there is a nice little curved ledge inside the cases that is just right for the reed assembly.

232929

So the reed should fit Ok

232927

Now I have to make up a spacer plate and reed block assembly, how hard can that be???..... :scratch:

[Ivan]

how many horses are you planning out of this bike?

[speedpro]

So why do they make the duct entry the same or a little smaller than the transfer port window now? Is it to reduce the gas velocity out of the port?

More likely to "increase" the gas velocity in the duct. Keep in mind also that the port window is only ever fully open for a very small portion of the cycle. There could be a good case for reducing the duct size depending on application.

[TZ350]

how many horses are you planning out of this bike?

On this engine I am working to a Wobbly design based on the RGV cylinder and of course the final result is as much about workmanship as the design.

So I hope to do Wobblys design justice with my efforts and not let him down.

If the TF/RGV100 is anything like the Wobbly engine Speedpro built then it should be 30+ rwhp and have a good wide power spread of about 3.5-4k rpm and be quite useable.

232953

You can see in this earlier dyno graph that Speedpros Wobbly 100 has a better spread of power than my 125. I expect that has a lot to do with the Wobbly-Pipes designed expansion chamber.

[TZ350]

Wobbly sent me an email (and permission to post it) re the shape of the RSA rotary valve disk. I had thought the soft closing may have been to extend the crank case packing by having a reducing inlet port window towards the end of the inlet period instead of a sharp cut off but it turns out it was more for mechanical reliability.

Interestingly the timings are much the same as I have been using on the GP, albeit the GP has a smaller inlet duct and port window,


Hi Rob
Here is a pic I just got from Frits, I asked about the RV timing as I am building up a Sim of the RSA/RSW.

He said that the opening wasn’t critical between 140 and 145, the closing between 85 and 88 depending upon the rider and track.

He said they tried opening timings all the way to 155*, but 142 to 145 was the norm.

The angle on the closing side is purely to help with wear on the case.
cheers
Wob

232958

[kel]

He said that the opening wasn’t critical between 140 and 145, the closing between 85 and 88 depending upon the rider and track.

He said they tried opening timings all the way to 155*, but 142 to 145 was the norm.

232958

Is it just my eye or did they forget to tell the other teams?

232959

[wobbly]

That pic is cited by Frits as "a radical example".
My opinion of closing angle (the important number) is that the later RSA has a much narrower port width than the RSW, and thus these timings give
a much increased STA, as the disc is covering the port for less time, with the same actual timings.
Thus maybe that engine can deliver better performance within an envelope of non "radical" port timing numbers.
In the old Rotax tandem twin, going from 85* ( stock) to 88* is like night and day in overev performance, but carburation becomes finicky and alot of bottom end power is lost.

[TZ350]

233003

Av doing the data capture while Keith runs up her 09 Honda RS on the dyno.

http://www.youtube.com/watch?v=2fTE6AfPbUg

[TZ350]

233019

Who knows if it's a good idea or even practical, but some time I am going to try an intercooler to see if we can chill the induction air.

[F5 Dave]

you could just move to Waiouru:innocent:

[TZ350]

233028

Some unkind person .... :bleh: .....pointed out today, they had done the math and that when Av rides his 22hp bucket I would need 55hp to have the same power to weight ratio as her.

No wonder her bike zips out of the corners so fast.......... and I burn clutches.

[Henk]

So go on a diet :chase:

[TZ350]

So go on a diet :chase:

Nope...... wrong answer, the correct answer has to be 55hp. :laugh:

[koba]

233019

Who knows if it's a good idea or even practical, but some time I am going to try an intercooler to see if we can chill the induction air.

Wouldn't that really only be effective if it was super hot to begin with?
Like coming out of a turbo...

It's really quite staggering how hot the compressed air from a turbo gets!


233028

Some unkind person .... :bleh: .....pointed out today, they had done the math and that when Av rides his 22hp bucket I would need 55hp to have the same power to weight ratio.

No wonder her bike zips out of the corners so fast.......... and I burn clutches.

If Aprilia managed 56 with a 125...

Hell, its only 550 hp per litre if you do it with a hundred...

hmmm, maybe losing weight as well as gaining HP is the go...

Get all anorexic and lose lots of weight...

Still not enough! hmm, cut a leg off...

Nope still not enough, another...

Nope, maybe one arm could re-jig the controls to suit...

Is that what people mean when they say: "Pushing shit uphill".

[bucketracer]

Wouldn't that really only be effective if it was super hot to begin with?

Yes your right, can't cool the incoming air that's at ambient temp below ambient by just using more air at the same temperature. But as anyone knows who has stood around in the wind wearing a wet Tee shirt, the evaporating water really chills things off. So maybe if TeeZee wears a wet T shirt over his leathers the idea could work.

[koba]

So maybe if TeeZee wears a wet T shirt over his leathers the idea could work.

Could work really well if it scares all the competition off...

[Buckets4Me]

Nope...... wrong answer, the correct answer has to be 55hp. :laugh:


wrong again it's 60 h/p:facepalm:

[TZ350]

...... maybe if TeeZee wears a wet T shirt over his leathers the idea could work.

Watch out or you might just get flicked with a wet T shirt! http://www.youtube.com/watch?v=EdUcfab-J_A

[richban]

233019

Who knows if it's a good idea or even practical, but some time I am going to try an intercooler to see if we can chill the induction air.


Cool air makes power. Sounds like a good idea to me.

[TZ350]

I hope this works.........

Rick has posted the results for Mt Welly, its exciting to see that the strokers are making a come back.

1st in the 1st A grade, 2nd 3rd and 4th in the second A grade race, the fast oil puddlers are still looking hard but now, not impossible to beat on a regular basis.

More and more I am convinced that outright power at Mt Welly dosen't count for that much, its more about the engines drivability and that once you have sufficent power one needs to look at increasing the power spread and punch out of the corners.

I have some ideas to try on the 27hp setup, the 27 because that already has a good power spread, the 30 is a bit vertical..........

[F5 Dave]

So you are saying that high horsepower might not win on the track. . . .Well yeah, but as long as it wins on the internet surely that racing stuff is just secondary to the real sport.

[TZ350]

So you are saying that high horsepower might not win on the track. . . .Well yeah, but as long as it wins on the internet surely that racing stuff is just secondary to the real sport.

Yes, yes your quite right, that racing stuff is so ho hum :sleep:, ones opinion of what the "The Real Sport is", depends on what your good at I suppose.

Winning in the workshop and on the internet, now that is an inteligent and skilled sport ........ top me if you can. :laugh:

And todays internet fast bike is tommorows track winner in the right (not mine) hands.

So I am pleased to have played my part in it and to have shared what we are doing to get there so that other stroker nuts can enjoy the fun too, as we all strive to unseat the dominant 4-strokes.

[F5 Dave]

and so we move to the next logical technological battlefield where the old guard are no longer king; the photoshop dynochart warriors.

Run for your wives

[quallman1234]

233003

Av doing the data capture while Keith runs up her 09 Honda RS on the dyno.

http://www.youtube.com/watch?v=2fTE6AfPbUg

Do we get a Dyno Graph along with that one ;). :bleh:

[jasonu]

and so we move to the next logical technological battlefield where the old guard are no longer king; the photoshop dynochart warriors.

Run for your wives

Bit harsh mate...

BTW I have overlayed the dyno graphs posted from all of the recent 'big hp' bikes, both 2 stroke and coal burners and my 12 year old 24.8hp KE still looks good. Now with 4 more HP on top with the same spread it might be dangerous.

On a side note, I was recently in a discussion about 'dyno technique'. One side (me and other animals) say small bore bike ie buckets dyno runs should be done in 3rd or 4th gear, no higher, assuming a 6 spd box. Any higher and the clutch will get hammered and possibly (probably after a few runs) slip. I seem to remember both Green and TZ talking about 'dyno sessions cut short due to clutch slippage'. I am curious to know what gear they do their runs in and am betting they both use higher or even top gears. Also, a top gear run might tend to make the curve look better than it really is as the bike is slower to gain revs which makes the curve look less peaky.

Does the gear the run is done in affect the actual result and/or figures? I think not as the motor doesn't know or care what gear the box is in and will make the same power regardless of gear sellected. Any knowegable comments on this one? Wobbly?

[F5 Dave]

I always run 4th for small bikes.

Taller gears will load slower & may produce different carburetion characteristics & posibly temp differences, but a 1 run won't have anywhere near as difference as an all gears run. Theoretically you should be able to overlay your (whatever gear) curve over an AG run & often this is true, but some bikes cough a bit between changes & load up (big inlet timed piston porters or rotary valves) & this can change how the next gear runs through. It will also show up fueling starvation in higher gears, or worsening heat build up in piston/pipe of advanced timing.

I would be interested (not that I have one, just for interest sake) in Waynes take on rotary valve tuning for consistent performance through the gears, though maybe this isn't an issue except for desperate tuning with crappy old tech carbs.

[jasonu]

I always run 4th for small bikes.

Taller gears will load slower & may produce different carburetion characteristics & posibly temp differences, but a 1 run won't have anywhere near as difference as an all gears run. Theoretically you should be able to overlay your (whatever gear) curve over an AG run & often this is true, but some bikes cough a bit between changes & load up (big inlet timed piston porters or rotary valves) & this can change how the next gear runs through. It will also show up fueling starvation in higher gears, or worsening heat build up in piston/pipe of advanced timing.

I would be interested (not that I have one, just for interest sake) in Waynes take on rotary valve tuning for consistent performance through the gears, though maybe this isn't an issue except for desperate tuning with crappy old tech carbs.

Mostly agreed especially heat build up on top gear runs. If you do an overlay of course you will 1st have to replot each resulting curve on a
new graph so the graduations on the x and y axis are the same, especially if the runs are done in different gears and on different dynos.

[TZ350]

I have overlayed the dyno graphs posted from all of the recent 'big hp' bikes, both 2 stroke and coal burners and my 12 year old 24.8hp KE still looks good. Now with 4 more HP on top with the same spread it might be dangerous.


My point exactly, to be dangerous you don't have to have the most hp you need to have the right sort of hp (power spread).


On a side note, I was recently in a discussion about 'dyno technique'. One side (me and other animals) say small bore bike ie buckets dyno runs should be done in 3rd or 4th gear, no higher, assuming a 6 spd box.

Does the gear the run is done in affect the actual result and/or figures?

We realy don't know.

The GP has a 5 speed box, we have been doing our dyno runs in 4th as that is closest to 1:1 through the box and 5th is overdrive at 0.8:1.

I think the Dynojet we use was basically made for people who load a bike, push a few buttons rev it up and get a graph without knowing to much about the science of it.

Which is pretty much us at the moment, but we would like to know more about the pitfalls to look out for and good dyno techniques so we can make better dyno measurements, any positive input based on experiance is welcome.

233284

My two engine setups compaired to Speedpros engine (green line). (red line runs were cut short as the vibration became excessive)

Another possible problem is that when you compair different bikes you also have to choose which one of the overall gear ratios to graph things with, I am not sure if this distorts things or not, but its possible.

[bucketracer]

..... just secondary to the real sport.

I am sure your right, there is only one true religion........ yours.

[wobbly]

Several points to consider.
The dyno load ( gear ratio) should be selected to simulate the end use.
ie do you want the thru the gears performance as seen at Mt Welly or pulling 6th gear for several seconds at Taupo, where you have a huge wind drag factor to push against.
Around a sprint track you can use way more timing and not see deto due to the short "power on" period.
But either way the heat soak in the pipe and case should be similar to what would be seen on the track.

The only reason that the clutch slips in the taller gears is because its a crap clutch pack and needs more plates or more spring to take the applied torque.

Re the rotary valve timing.The problem here is that every engine is different, with the case vol interacting with the timing and the carb length/size.
Basically when you exceed 140/88 you get finicky jetting and questionable power increases at the expense of drive down low.
Only way to define what is best is to leave the closing at say 88 and go from 135 up to 145 in 2* increments.
Stop or go back if no useable power is seen.
Then see if top end is lost by going back to 86/84 on the closing.

Graphing power Vs rpm takes the load out of the equation,but it is unrealistic to back to back a cold engine in 3rd, against a stinking hot all gear run up to 6th.
Not apples for apples.

[F5 Dave]

Thanks for the response. What do you think about high rpm coughs between gear changes? sometimes they appear on bikes with tame, well, not radical inlet durations (piston port & rotary).

[wobbly]

See this all the time in kart racing - reeds as well,usually its the needle/tube combo going lean as you pass thru 3/4 throttle, when backing off for the change.
Get an Ignitech on there and do full throttle shifts - easy.

[F5 Dave]

hmm, sounds plausible.
yeah I used to see it on my RG, 1/2 piston port, 1/2 case reed. I used to shift full throttle using the clutch, (had a 12deg baffle so it wouldn't go past 12,500), but sometimes it coughed like buggery. Sometimes, usually at the wrong time.

My next engine with same mx ignition, a substantially different pipe, similar inlet port, lower exhaust & higher transfers doesn't do it.

I've theorised but couldn't hand on heart say I've nailed why.

[wobbly]

Also happens when an engine is reved too far past peak power before a gear change.
The airflow drops in the overev, the carb goes lean and it will backfire as the change is made ( even using a speedshifter).
RS125 engines in karts do it with steep baffles, as soon as you rev them too hard.

[F5 Dave]

Now this makes more sense, my baffle taper is now 2 stage & less steep than previous setup. The engine used to brick wall so clearly the airflow was well out of sync at past power revs. Thinking more about it I'd developed this changing routine on the dyno with an all gears run as it appeared to give the least drop off on a peaky engine. And it worked most of the time, but I guess if borderline lean & a slow change & more revs than normal that it would occasionally cough. Often late in the race when everything was pretty hot.

I'd assumed in the ex side & thinking about it I can see how this may well stop the airflow, however the scavenging should continue. . . .hmm, been a busy day at werk so I may have to reflect on this later. But if the suction drops right off suddenly then for combustion to continue it still needs the correct mixture ratio, so what you say makes perfect sense. Thanks for the brain food. I'll have to digest.

[wobbly]

Its not scavenging thats directly the issue, its lack of blowdown time, that effects scavenging efficiency and delivery ratio .
Means the cylinder is full of exhaust residuals, as much of the mixture waiting in the ducts is reverse flowed back into the case.

[TZ350]

Clip taken from the back of my bike. A grade points race. Avalon was riding the bike. She went real well with a 3rd place:niceone:

http://www.youtube.com/watch?v=eYEe8gIzs2I

Av riding NedKellys RS/GP125 (Team ESE) bike to third place, in the 2nd A grade race.

This engine has done several Taupos, 3 x 2-Hours and numerus races and is now the least developed bike in the ESE stable and is due for a bit of an up grade.

233402

NedKellys dyno graph.

The details of how his engine was made and the relativly few simple mod's involved are on page 200 for anyone who wants to have a go at one of these for themselves.

[TZ350]

Searching for the sweet spot.

Receved some Mallory metal slugs from Wobbly today. They are about 19mm in dia and about twice the weight of steel.

I calculated that I needed about 45g to get a balance factor of 52%. Which is lucky because that is equivalent to one slug.

So, cut a slug in half by holding the slug in the lathe and while it was spinning I cut through it using a slotting blade in a hand grinder.

Drilled some 19mm holes and squared the bottom of the holes with a butterfly drill.

Glued the Mallory plugs in place and center punched some dimples around them for extra security.

Job done.

[gatch]

Searching for the sweet spot.

Receved some Mallory metal slugs from wobbly today. They are about 19mm in dia and about twice the weight of steel.

I calculated that I needed about 45g to get a balance factor of 52%. Which is lucky because that is equivalent to one slug.

So, cut a slug in half by holding the slug in the lathe and while it was spinning I cut through it using a slotting blade in a hand grinder.

Drilled some 19mm holes and squared the bottom of the holes with a butterfly drill.

Glued the Mallory plugs in place and center punched some dimples around them for extra security.

Job done.

Butterfly drill ? What is that ?

[TZ350]

Butterfly drill ? What is that ?

I did a quick search on the net, only found one reference to a butterfly drill, so it looks like I am prety much the only one calling it that. :o I should have called it a flat bottom drill which is a bit like a sheet metal drill.

233561 233562 233563

I drilled an ordany hole first then flattened the bottom until the Mallory slug fitted flush with the face of the flywheel.

A good reference to sharpining or re-shaping drills:- http://users.bart.nl/users/summer/16mmngm/Articles_htms/ColinBinnie/DrillSharpening.htm

[gatch]

I did a quick search on the net, only found one reference to a butterfly drill, so it looks like I am prety much the only one calling it that. :o I should have called it a flat bottom drill which is a bit like a sheet metal drill.

233561 233562 233563

I drilled an ordany hole first then flattened the bottom until the Mallory slug fitted flush with the face of the flywheel.

A good reference to sharpining or re-shaping drills:- http://users.bart.nl/users/summer/16mmngm/Articles_htms/ColinBinnie/DrillSharpening.htm

Ohhh, I see. I've never heard it being called that ha. I usually use a slot drill to flatten out blind holes. As I can't be arsed re grinding the points..

[koba]

My old man spent a huge amount of time in his apprenticeship sitting in front of a grinder sharpening drills all day. Consequently he is quite good at it, hand him a drill and he can sharpen it PERFECTLY in a few strokes without even looking at it!

[gatch]

My old man spent a huge amount of time in his apprenticeship sitting in front of a grinder sharpening drills all day. Consequently he is quite good at it, hand him a drill and he can sharpen it PERFECTLY in a few strokes without even looking at it!

I sharpen something just about everyday, ASSAB tools, drills, carbide tools, knives, machine blades, my fingers..

The trickiest thing so far is renewing little drills. Like below 4mm. A girl on my pre trade course ages ago was amazing at it. Tiny little fingers and real delicate touch. Not me though, I can barely see them hahaha. True story.

[koba]

True, I think the trick is getting the skills well sorted before the eyesight fails.

[wobbly]

If you have any issues with the Mallory coming loose ( hope you dont) you can Tig weld them in place.
In the stroker Banshee/RZ/LC cranks I build, they are 0.08mm press fitted, then Tig tacked each side.

[gatch]

If you have any issues with the Mallory coming loose ( hope you dont) you can Tig weld them in place.
In the stroker Banshee/RZ/LC cranks I build, they are 0.08mm press fitted, then Tig tacked each side.

You don't put a chain and padlock around them just to be sure ??

[TZ350]

Filched from another thread. Some Engine machine shops that can do small cylinder re-bores.........


Carr Engine Services ,Carr Rd Mt Roskill.


Enpro in Onehunga.


Empro don't go small enough, but Carr can
cheers


Scott Sampson at Glenn Dene Engine Reconditioners has been doing all my machining work for bl**dy years - his workmanship is beyond reproach & his charges are realistic...

*** VERY MOTORCYCLE FRIENDLY, HAS THE SKILLS & GEAR TO DO THE JOB RIGHT FIRST TIME EVERYTIME ***

31D Cartwright Road
Glenn Eden Waitakere City Auckland Ph: 09 818 5352 Fax: 818 5225 Mob: 021 711 595 E-Mail: glendenerecond@xtra.co.nz


Wade Automotive. cnr Church St and Gt South Rd Onehunga (by the Southern Motorway on ramp) they have bored my 43mm 50cc and 56mm 125cc Bucket race cylinders.

It pays to ring a reconditioner first and find out if they have a boring bar small enough for your cylinder, and also if they have to change it over to do your cylinder because if they do, they will probably leave your job till last or never if they are busy.

Also a small cylinder can cost more than a big one because of the change over and then back time involved.

[bucketracer]

[B]Has anyone seen this months (March 2011) TOP GEAR magazine?

There is a really cool article on last years 2 hour,held in Auckland, Pages 38,39,40.

A few of the boys got a pic in there. Tim Fraser, Dave Manuell, Gary Cunningham. There's a real good one of the Le Mans start.

They are full of praise for JC (John Connor) and he deserves it too !!!:first:

They loved the racing and were impressed by the riders abilities.
I'm going to buy the magazine, just for the bucket racing pages.
Oh yeah there's a few nice looking cages in there too, I spose!!!!!!

A good picture in there too, of Peter (Indian Motorcycles) and Josh Walby (Team Pepsi) working on their bike.

233664233663233662

Ooops the images are back to front, best read them with a mirror or ...........

233667

Buy a copy of Top Gear, March 2011 from your local Book Store or Petrol Station...........

[RMS eng]

Av riding NedKellys RS/GP125 (Team ESE) bike to third place, in the 2nd A grade race.

This engine has done several Taupos, 3 x 2-Hours and numerus races and is now the least developed bike in the ESE stable and is due for a bit of an up grade.

233402

NedKellys dyno graph.

The details of how his engine was made and the relativly few simple mod's involved are on page 200 for anyone who wants to have a go at one of these for themselves.
nice power curve,mark beat her in the first race on his 16hp ts100 which makes more bottom end power,have a new pipe to fit and get the power up to 20hp.

[bucketracer]

The powerjet carb is controlled by the Ignitech with a combination of throttle position and rpm in a "truth table".

In general the solenoid is activated with 12V ( no fuel flowing) below 4000 rpm and 75% throttle on the TPS.

Above 75% and around 12400 rpm it is activated again to lean off the fuel curve over the top of the pipe.

And something that I scraped from the net.........

""The solenoid control on TZ type powerjets really just shuts off fuel flow to the powerjets right at the top of the rev range to lean the mixture off to increase the over-rev once you are past peak power.

I don't have the solenoids plugged in currently though as I find they work well enough for my current needs with the powerjets simply responding to venturi vacuum pressure in pretty much the same way as the oem 3MA powerjets work.""

233787233788

And here is a picture of the carbs and what I can make out, a dyno graph without, and with the power jet solenoids shutting off (red line) and extending the over rev.

So it looks like you can use an electric power jet like a standard one and when the carburation is sorted, try switching it of by activating the solenoid at or just after peak power and see what happens with the over rev.

[wobbly]

You have to be very carefull with the switch point and the run time on the dyno.
The switch point is dead critical to 100rpm,so i always set it too high initially and make sure that the dyno is loading the acceleration rate to be as close to that on track as you can.
This gives the pipe time to heat up and affect the power over the top, as it would in reality.
On a RS250 dropping the switch point from 12800 ( std) to 12400 gives easily another 800 rpm of virtually no power drop past peak.
On the track,if the rider can feel the switch point ( it feels like hooking another gear)the jet is too big,when its right it should be seamless and just keep reving out.
Leaded fuel is the opposite to unleaded, in that as leaded likes to run lean - you can only use a small powerjet and thus only switch off a small amount.
A leaded engine works best with around 35 to 38 PJ, the unleaded fuel can switch a 60, in Keihin numbering, as the crap fuel makes best power at peak when quite rich..

[TZ350]

Thanks Wob and Bucket, now that I have some idea of how its supposed to work it has given me a bit of confidence to try the electronic power jet.......

[TZ350]

Taller gears will load slower & may produce different carburetion characteristics & posibly temp differences, but a 1 run won't have anywhere near as difference as an all gears run. Theoretically you should be able to overlay your (whatever gear) curve over an AG run & often this is true, but some bikes cough a bit between changes & load up (big inlet timed piston porters or rotary valves) & this can change how the next gear runs through. It will also show up fueling starvation in higher gears, or worsening heat build up in piston/pipe of advanced timing.

Its not one of our bikes but the only all gear run that we have recorded..........

233828

It would be interesting to know what some of the features on the graph mean, like the little peaks at the begining of each run.

[F5 Dave]

That's pretty nice power. First gear is always crap , heaps of torque difference & 2nd doesn't always clear out fully. Seems a bit odd that the curve changes so much through the higher gears (6 speed), & top looks fine, maybe a rich bog whilst changing with lessening effect under more load?

I'd be wary of gear change technique creating variables. find what works best for that bike & be consistent.

Where are all these high power bikes coming from?

[Buckets4Me]

Where are all these high power bikes coming from?


back yard sheds or under the house
sometimes in the living room and or bedroom :facepalm:

[wobbly]

In the lower gears you have to back off more to get it to change, and thus the fueling on the needle affects the changes more.
This is because the rev drops are way bigger in the lower gears.
1st to 2nd you may well have 3000 rpm drop into the next gear, 5th to 6th may only be 600 rpm
I would say its rich on the pilot then goes lean as the needle is lifted.
The pipe is getting hotter with each change as well, this may or may not give more power, depending on how close to optimum the pipe is to start with, and how lean the main is - thus getting more heat as it revs out.

[TZ350]

Where are all these high power bikes coming from?


.....................Thomas and Bucket................


233869 233870 233872 233871 233878 233873

[TZ350]

You have to be very carefull with the switch point and the run time on the dyno.
The switch point is dead critical to 100rpm,so i always set it too high initially and make sure that the dyno is loading the acceleration rate to be as close to that on track as you can.
This gives the pipe time to heat up and affect the power over the top, as it would in reality.
On a RS250 dropping the switch point from 12800 ( std) to 12400 gives easily another 800 rpm of virtually no power drop past peak.
On the track,if the rider can feel the switch point ( it feels like hooking another gear)the jet is too big,when its right it should be seamless and just keep reving out.
Leaded fuel is the opposite to unleaded, in that as leaded likes to run lean - you can only use a small powerjet and thus only switch off a small amount.
A leaded engine works best with around 35 to 38 PJ, the unleaded fuel can switch a 60, in Keihin numbering, as the crap fuel makes best power at peak when quite rich..

Wob, thanks for the reply.

On the track, is it ok, to let the bike pull hard for an extended period on over rev in top gear like down the back straight of Puki or Taupo long track when the power jet is off (lean) and the ignition retarded?

Or should the power jet and ignition retard combo only be used in the lower gears?

TeeZee

[wobbly]

Thats the whole idea of retarding the spark and turning on ( fuel off) the powerjet.
This puts less heat into the piston, more into the pipe,to create overev power.
Its inherently "safe" as the bmep is low and the heat isnt going to sieze anything when you are over the top of the torque curve.

[TZ350]

Rebuilding the mallroy balanced crank.

Plenty of oil on the pin and in the pin hole.

234016

Using a V block to start the pin straight.

234014

A bit of time spent here aligning the flywheels saves a lot of time later.

234015

Getting the rod side clearance right, 0.5-0.6mm

234017

Checking that there is side clearance in the cases.

234018

Balance Factor, the percentage of reciprocating mass counterbalanced by the flywheel.

The counterbalance is 121g and the reciprocating mass is 232g so (121/232)*100=52% balance factor, lets see how that goes, last time the balance at 38% was so far out it frothed the fuel up and out of the tank when the bike was being dynoed, 46% was better but still frightening. I was aiming for 50 but 52% will do.

Original BF was 72% and vibrated as the rpm got up, with the balance holes plugged and the bigger pin and rod the BF became 38%, after drilling some holes in the big end area the BF moved to 46% now with the Mallory plugs and no drilled holes around the big end area its 52%.

I will keep changing it a bit at a time untill I find the sweet spot and it runs smooth in the rpm range where the power is, 9-13K rpm.

[wobbly]

Just a couple of points - I would consider 0.6mm as the very minimum of big end clearance for a race engine.
I shoot for 0.8 with 0.2 in the case.
Do you float the crank on the side not locked by the drive gear/nut, some cranks are not locked and can float the 0.2mm by polishing both main jounals - it does make a difference.
The other thing I just learned from Overmars, Aprilia ( Jan Thiel) found that anything under 1mm clearance anywhere on the crank lost alot of power, due he said to increased fluid shear of the A/F mixture.

[F5 Dave]

Hey Wobbly, at what point do you think clearance gets dangerous? Too much clearance is sited as causing rod breakages & I've seen a recently rebuilt crank break the rod of my MB at not much more than 12000rpm (20 years ago) but sadly didn't measure the clearance after the event (I assumed it was a cheapo Long brand Rod issue, the bearing still rotated fine) & I gave the crank back to the rebuilder but never saw it again.

[TZ350]

I would consider 0.6mm as the very minimum of big end clearance for a race engine. I shoot for 0.8.

My source was Bells book, thanks for the heads up and the more up to date thoughts on rod side clearance.

If the 0.8 is with the traditional large side-locating washers, would it be the same with my crank.

My crank uses the original RGV rod set up that’s located in the piston by thrust washers and the big end is much more open with small steel rings centralising the big end brg.

234111

Does this kind of big end setup need 0.8mm side clearance too?



Do you float the crank on the side not locked by the drive gear/nut, some cranks are not locked and can float the 0.2mm by polishing both main jounals - it does make a difference.

No, my crank is a light press fit in the ignition side brg, should it be a slip fit?

How does it make a difference to have the shaft a slip fit?

Wont the shaft spin in the brg if it was polished to 0.2mm clearance?


I just learned from Overmars, Aprilia ( Jan Thiel) found that anything under 1mm clearance anywhere on the crank lost a lot of power, due he said to increased fluid shear of the A/F mixture.

Does Frits mean there should be at least 1mm clearance between the side of the flywheel and the crankcase wall and also the flywheel rim and the case.

I can see my crank coming apart again for some modification......... :facepalm:

[kel]

Does Frits mean there should be at least 1mm clearance between the side of the flywheel and the crankcase wall and also the flywheel rim and the case.

I can see my crank coming apart again for some modification......... :facepalm:

Frits Overmars
Sujet: Re: [GP125] Caractéristiques Aprilia RSA Mer 8 Déc - 13:36
In theory enclosed cranks are good. Jan Thiel did some experiments at Aprilia with a kart engine that had its reed valve at the front: the incoming mixture had to move against the direction of crank rotation. And although the crankcase stretched over the crank webs, reversing the direction of rotation brought another HP. So the crankshaft does have an influence.
But in practice, if you reduce the distances between crankshaft and crankcase walls to less than 1 mm, the viscous friction of the mixture between the surfaces really costs power at high rpm. And if you make the clearances so tight that lubricating oil can no longer reach the big-end and crankshaft bearings, it will also cost engines
Another negative aspect: any volume with a narrow 'entrance' between the crankshaft and crankcase surfaces acts as an hydraulic damper on the Helmholtz-resonance in the crankcase.
Aprilia has avoided this by making the space between the crank webs as wide as the big-end bearing. As a result the crankcase volume of the 125 cc RSA engine at TDC is about 650 cc, so the exhaust pipe really has some volume to breathe from.
So much for the fairy tale of high crankcase compression

[wobbly]

The 0.8mm clearance is for the "normal" big washer setup, so I cant say what would be the go with the open type - except to say that the whole idea of the 0.8 was to get more oil into the bearing and the open type wont have this issue at all.
The 0.2mm is side clearance, I just polish the journal such that the bearing inner race will "just" slide on by hand.
The floating crank allows the crank to move on the bearing as the case heats up and takes up all the side clearance in the main bearing.With it just floating the bearing will always centralise, thus reducing friction.
I would machine the case to get the 1mm clearance everywhere.

[koba]

The 0.8mm clearance is for the "normal" big washer setup, so I cant say what would be the go with the open type - except to say that the whole idea of the 0.8 was to get more oil into the bearing and the open type wont have this issue at all.
The 0.2mm is side clearance, I just polish the journal such that the bearing inner race will "just" slide on by hand.
The floating crank allows the crank to move on the bearing as the case heats up and takes up all the side clearance in the main bearing.With it just floating the bearing will always centralise, thus reducing friction.
I would machine the case to get the 1mm clearance everywhere.

Huh, waddya know!
I had a performance mod on my streetstock just by starting with a worn out pile of poop...

[Chambers]

It might not be Buckets but there is a lot about Av.

http://speedweek.com.au/?p=2168

Av riding her stocker against the super tuned 125's

Bit of talking head stuff in the beginning bit, but then it gets interesting with Av blitzing them off the start.

[Rick 52]

Good coverage cheers Chambers.

[ac3_snow]

I have spent most of the afternoon playing around with the new port calculator/analyzer I downloaded recently, and have been rather confused as to the desired figures that I'm after

After finding the screen shots TZ350 posted of his figures for the Gp125 through ther same program (the origional post now eludes me) and thumbing through Grahams Bells book again I was able to make something I perceived as progress!
234334
These are the figures I have at present, with the need to raise the ports by a further 1mm each. are these appropriate durations? (I will raise the barrel and take 1mm from the bottom)
I used the CAD application to estimate the shape I need for my exhaust port in order to get the required blowdown time area (I think?)

here is the port map of my barrel in its current unfinished form
234335
It's a TF125 barrell, what I'm looking for is confirmation that I 'am going in the right direction, I'm not hundred percent sure that I utilized the program correctly either.
Any advise or constructive abuse would be much appreciated!

EDIT: I just realised the blowdown time area displayed on the calculator and the CAD application are different, I did have them equal at one point and assume this is the right thing to do?

[TZ350]

Ive been dabbling with this engine for sometime now, when TZ350 started his RGV project we got together and started working with Wobbly to acheive a reliable and fast package. Some things are different between our camps, cohice of bottom end being the main difference. Ive gone with a RG125 its similar to an rg150 but not quite the same.

Yow Ling sent me these photos of his progress, looks good and I hear there is another similar one being started in Christchurch too. So I had better get a move on with my own or I am going to be left behind.

234337 And thats one serious looking carburettor.

Other interesting pic's

[wobbly]

With 200 and 135 and no powervalve it would be a peaky piece of shit.
You can run 72% no problem on the Ex width and drop the timing, but unless the program spits out STA im lost.

[speedpro]

I note the spark plug is at the original angle and therefore you probably have the original combustion chamber. I got instant horsepower with no other changes other than welding up the head and putting the plug in the middle of a standard shape chamber. It was more power everywhere measured on a dyno.

[ac3_snow]

With 200 and 135 and no powervalve it would be a peaky piece of shit.
You can run 72% no problem on the Ex width and drop the timing, but unless the program spits out STA im lost.


would an exhaust duration of 195 be more acceptable or could it still be peaky? I'm assuming transfer durations are semi appropriate.
not entirely sure as to STA, only figures it gives are..
234353

[TZ350]

Handy porting calculator based on Jennings and Blairs work.

On the top right side you can toggle between Jennings or Blair. Blair gives you mean Blow Down Time Area.
Port durations are just a guide. its Port Time Area that is the true measure.

234352

Chose the rpm using the vertical yellow line.

Horozontal yellow line is for working out the Ex and Trans durations for your rpm.

The numbers along the top left are used for working out the port heights needed to get the durations indicated.

The round dial thing is for selecting the Power/BMEP you want from the rpm you have chosen. 9-10-11 bar BMEP is typical and whatever you chose here effects how much Blow-Down-Time area is required.

234351

Portcad starts with the data you entered, then you can adjust the ports in Portcad to get the Time Areas needed.

Top right, the yellow line that I drew shows you what Blair thinks you need for exhaust blow down time area based on the power and rpm you selected and bottom left what port cad calculates you have.

There is also numbers for transfer and exhaust time area.

Use port cad to adjust the ports, widths and heights to get the time areas you need, then go back and adjust the port heights to get the dimensions right.

Remember "Keep the Transfers Low and Wide" to increas blow down without increasing the exhaust port height (duration).

[TZ350]

I just realised the blowdown time area displayed on the calculator and the CAD application are different, I did have them equal at one point and assume this is the right thing to do?

Yes, you need to get them equall, the Calculator tells you what you need and PortCad tells you what you have.

234359

Looks like you are doing pretty well with the program.

Here are a couple of the things that I see in this PortCalculator picture.

In the Calculator window Blowdown mean area required is 2.20 and you have in the Cad window 1.97 so you have to change the shape of the exhaust port to get more blowdown area or increase the blowdown time by raising the exhaust port or lowering transfers and widening them to keep their Port-Time-Area where its needed.

In the Calculator window Ex mean area required is 6.37 and you have in the Cad window 6.15, so once again you need to increase the size of the exhaust port.

In the Calculator window Transfer mean area required is 5.22 to 9.34 and you have in the Cad window 6.28, so your OK there.

In PortCad the shape and size of the ports can be changed by pulling the little yellow dots around.

To the right in the PortCad window there are options for changing the angles of the ports and changes to the port angles change the calculated port areas.

The headings "Int Mean Area" and "Intake Total Area" in the PortCalculator window are confusing names as they relate to the Transfers and not the Inlet Port.

[TZ350]

would an exhaust duration of 195 be more acceptable or could it still be peaky?234353

Remember, its all about getting the "Blow-Down-Time-Area" needed for the RPM and Power your looking for.

Everything else is adjusted to achieve that as well as having enought Port-Time-Area of their own to do their own jobs like exhausting, transfering and inletting.

[ac3_snow]

Yes, you need to get them equall, the Calculator tells you what you need and PortCad tells you what you have.


ok thanks alot, should have been able to figure that one out myself :sleep: haha was slowly coming around

The transfer port designs in the CAD application are all standard, have'nt changed any of those yet so that will be my next step.
In terms of duration I 'am currently stuck with the minimum of 195 for my exhaust port (although a new barrell should arrive tomorrow with any luck, will be more careful with the next one)

as for power I would be happy with a measly 20-22hp at the wheel as long as its reasonably well spread. I will have to have another look at things now that I kind of almost know what I'm doing

EDIT: so wider ports = less duration.... which would make a broader power spread?I'm sure theres more to it that that but how do I avoid creating, in your wonderful words wobbly, "a peaky peice of shit"?

[TZ350]

as for power I would be happy with a measly 20-22hp at the wheel as long as its reasonably well spread. I will have to have another look at things now that I kind of almost know what I'm doing

You are doing very well, it took me ages, you have the right program for seeing if 20-22 is possible given whatever physical limitations the castings around the ports might impose on the porting you can do.

Once you know the RPM and BMEP you can use the spread sheet I have posted somewhere (try looking on the decade pages 140-130-120 etc) to work out the pipe dimensions you need. The spreedsheat is also based on Blairs work so should give you a good starting point.

[TZ350]

..... so wider ports = less duration....

Yes, you don't have to use the durations shown in the Port Calculator, they are based on the earlier work of Jennings and are the starting point but you do have to pay real attention to the mean Port-Time-Area's based on Blairs work.

And the final durations and port widths are the measurements for the ports so you can make them. PortCad also prints out a port template for you to use.

Wider is good, and especialy with the transfers, wider is very helpfull for fitting the required blowdown time area between the exhaust and transfers and for reducing the ex port duration (you can also reduce the Ex duration if you can increase the Port area) but about 70% of the bore dia is generaly regarded as the max reliable width for an unbridged ex port.

To get a realy low wide ex you need a bridge or multiple exhaust side windows.

There are lots of compromises to make, its all a juggling act (The Black Art).

Anyway thats how I understand it and if I have something wrong hopefully Wobbly will pick it up and set us straight.

[TZ350]

Just a couple of points - I would consider 0.6mm as the very minimum of big end clearance for a race engine.
I shoot for 0.8 with 0.2 in the case.
Do you float the crank on the side not locked by the drive gear/nut, some cranks are not locked and can float the 0.2mm by polishing both main jounals - it does make a difference.
The other thing I just learned from Overmars, Aprilia ( Jan Thiel) found that anything under 1mm clearance anywhere on the crank lost alot of power, due he said to increased fluid shear of the A/F mixture.

Yet Another Crank Rebuild

234517

After a bit of machining, 0.8mm rod side clearance and 2mm clearance between the flywheels and the case every where else. A slip fit inside the outboard main brg and 50% ballance factor.

[Bert]

Something a little off the current topic;
Not even sure if it will work; but we will see...
one of the things I've been struggling with (with my build) is resolving the head and squish etc. the standard head could be welded up and re machined but i didn't really like the location of the sparkplug (distance away from the piston; which meant everything was always going to be a compromise...) so we have done something different.

so this is what we started with, standard TZR head complete with crappy noise reducing squish (apparently), welding this was never really going to work out well:
234615

So we made a Homemade VHM head (water galleries to be cut). Surprising amount of meat in the cast head.
234616

so now we have a nice two piece, fully o-ringed head, sparkplug passes through the original head into the insert. all hopefully will hold together with the standard head studs :confused::
234618

currently the insert is in blank form, but that's the next step. :wait:
234617

if it works I'll be stoked.

[TZ350]

so this is what we started with, standard TZR head complete with crappy noise reducing squish (apparently), welding this was never really going to work out well:
234615

So we made a Homemade VHM head (water galleries to be cut). Surprising amount of meat in the cast head.
234616

so now we have a nice two piece, fully o-ringed head, sparkplug passes through the original head into the insert. all hopefully will hold together with the standard head studs :confused::
234618

currently the insert is in blank form, but that's the next step. :wait:
234617

if it works I'll be stoked.


Very interesting Bert, looks good, I reckon it will work a treat........ :yes:

[TZ350]

All because someone asked.

BMEP or Break Mean Effective Pressure as I understand it.

BMEP is not a real thing ………. I have always wanted to say that….

BMEP is not real, 2+2=4 is real but BMEP is not, its one of those things like the stick and ball models of atoms and molecules we all saw in science class at school.

Those models are not like real atoms, real atoms are clouds of uncertainty and require complex math to understand. The models are just simple (but very good) concepts to help us get our heads around something quite complicated.

BMEP is like that too, a concept to help us get our heads around something complicated.

A motor sucks, compresses, bangs and blows gas in a complicated way. And you can easily see that there are all sorts of positive and negative pressures on the piston during a 2 or 4 stroke cycle.

It would get messy quite quickly trying to keep track of all those positive/negative pressures and there is certainly no easy way of measuring these pressures individually and then adding them all up.

But the sum result of all of them can easily be measured as hp and hence the simple concept of BMEP

BMEP or Break Mean Effective Pressure. Break for hp, Mean for average, Effective for sum total, Pressure for force and BMEP is commonly expressed in Newtons cm2, PSI or Bar. 1 bar is basically one atmosphere or 14.5psi aprox and 1 Newton cm2 is 1.45 psi aprox.

BMEP is regarded as the amount of force that you need to exert on a piston to generate the same torque at the crankshaft as generated by the measured hp.

So BMEP can be calculated from crank hp and rpm or you can calculate hp if you know the rpm and the BMEP at that rpm.

Remember, basically hp = torque times rpm

Or work done = cranking force times how fast you can spin the crank around.

Try crank starting an old car to see what I mean about “work done” or the size of your persional hp.

To get more hp, (more work done), you need more torque (to work harder) or to spin the crank faster (work quicker) or both.

Now, torque comes from the heated combustion gas pressing down on the piston. To get more torque (and therefor hp) you need to heat the combustion gas more to get more effective pressure.

There is a direct correlation between torque and the concept of BMEP, and the hotter the combustion gas the hotter the mean exhaust gas temperature will be and the higher the resulting Torque and indicated BMEP.

In a 2-stroker a BMEP of 9 Bar results in about 500 deg C mean exhaust gas temp and 11 bar its about 600 from memory.

So, say you designing a motor for 25crank hp (22 rwhp) and knowing the rpm your going to run, the BMEP required equates to a BMEP of 10bar then you know that the mean exhaust gas temp will be 550deg c.

You need to know the exhaust gas temp as the speed of sound is faster in hotter gas, and slower in cooler exhaust gas.

Now that you know what the exhaust gas temp will be, you can design a pipe with the right tuned length for the rpm your intending the motor to run at.

BMEP is a concept tool that ties Carburettor size, Air/fuel consumed, Port-Size, Hp, Torqe, Combustion-Temp and Ex-Temp together.

As a rule of thumb, for a 4-stroke the BMEP should be better than its cranking pressure and a 2-stroke is close, but a little less than its compression pressure.

BMEP is a much more appropriate tool than hp or torque for comparing the performance of different engines.

This is, as I understand it, a quick Google will bring up a lot of info on BMEP what it means, how to use it and formula for calculating it.

[wobbly]

I simply dont "get" the correlation between bmep and Ex gas mean temp at all.
It is entirely possible to set up an engine to produce X - Hp at just about any reasonable mean temp.
The gas temp affects the pipe dynamics, and is a function of the static compression, the ignition advance, and just as importantly the dynamic compression ( that is achieved by the delivery ratio X the trapping efficiency).
We can achieve the same power using unleaded fuel running very rich with lots of advance and no com, this would give a header temp of say 1050F.
On leaded Avgas, the tuning combination would be very different , but the header temp for best power on that fuel would need to be over 1200F.

You use the bmep to correlate the port STAs with the Hp target.
The pipe temp is a separate function that dictates the pipe length needed to work with the Ex duration you have derived from the STA calcs.
The 9 Bar engine can be run at 500C or 600C, it all depends upon the tuning approach, and the fuel used, as to what the mean temp in the pipe ends up being.

[TZ350]

I simply dont "get" the correlation between bmep and Ex gas mean temp at all.

You use the bmep to correlate the port STAs with the Hp target.

The pipe temp is a separate function that dictates the pipe length needed to work with the Ex duration you have derived from the STA calcs.
The 9 Bar engine can be run at 500C or 600C, it all depends upon the tuning approach, and the fuel used, as to what the mean temp in the pipe ends up being.

Thanks for adding to that, from reading Blair, I had formed the impression that mean ex temp was directly related to BMEP.

Could you please explain STA. TA I guess is "Time Area" but the "S"?

[k14]

So we made a Homemade VHM head (water galleries to be cut). Surprising amount of meat in the cast head.
Aren't those inserts made for competition engines? :devil2:

Be careful when machining, I know of a couple being stuffed up by fairly experienced machinists.

[kel]

Could you please explain STA. TA I guess is "Time Area" but the "S"?

Specific Time Area.
Time area, and the ratio between port window area and cylinder volume - according to Jennings

[TZ350]

Specific time area. Time area, and the ratio between port window area and cylinder volume - according to Jennings

Specific Time Area is that another way of saying Port Time Area or is there a difference?

[wobbly]

Specific time area (STA) is an indication of the effective port window area that has to be open for a certain length of time to allow enough gas to flow through the port to achieve the target power at the target rpm for that specific engine capacity.

Time/area is just that, a hole with a certain area that is open for a certain time period.

STA has time/area derived from the port and the rpm,plus the relationship of that to the cc of the cylinder.

[wobbly]

Just one thing to be aware of re machining the crank for case clearance.
This will drop the CCR and thus the signal seen at the carb.
You will need to go richer everywhere to compensate, more so in the bottom and middle.

[TZ350]

The gas temp affects the pipe dynamics, and is a function of the static compression, the ignition advance, and just as importantly the dynamic compression ( that is achieved by the delivery ratio X the trapping efficiency).

We can achieve the same power using unleaded fuel running very rich with lots of advance and no com, this would give a header temp of say 1050F.
On leaded Avgas, the tuning combination would be very different , but the header temp for best power on that fuel would need to be over 1200F.

The pipe temp is a separate function that dictates the pipe length needed to work with the Ex duration you have derived from the STA calcs.


From reading Blair, I had formed the impression that mean ex temp was directly related to BMEP.

But a moments thought would have shown me that its not as close a correlation as I had thought.

I was reminded by your post that the ex temp can also be affected by fuelling and ignition advance (amongst other things).

And of course on our own engines we are retarding the ignition and leaning out the mixture by closing the electric power jet so as to heat the ex gas in the pipe and thereby extend the over rev.

[TZ350]

Just one thing to be aware of re machining the crank for case clearance.
This will drop the CCR and thus the signal seen at the carb.
You will need to go richer everywhere to compensate, more so in the bottom and middle.

Thanks for the heads up, I had not got the mixture right with the new setup anyway, particuarly coming back on the throttle, and especially throttling on again from the bottom end after shutting the throttle on over run.

[TZ350]

234636

234635

Getting it back in the case, the clearance around the flywheel doesn't look as bad as I thought it would.

234634

The shadows make the side clearances look bigger than they actually are.

Std the case clearance is 1mm around the flwywheel, it is now 2mm every where between the flywheel and the case.

After a lot of work the balance factor is exactly 50%.

Clearance and balance factor are the only changes, so it will be interesting to see how it goes on the dyno next week.

First up I will run with the old carb, then if things are working ok I will try the new electric power jet carb and if all that goes well and we are getting good over rev at the top I will try water injection to see if we can extend the lower part of the power spread.

[wobbly]

Dont waste your time and energy re water.
Honda did it with full PWM solenoid control - it bumped up the bottom end really well, but the water mist in the pipe kept it cool for so long down the straights that the engine never really recovered in time to get the top end back.
Another expensive blind alley.

[kel]

Your photo gives away that your injecting something direct into the cases, do tell.

[kel]

re the water injection (Ill dig out the article for you) Honda also stated they could achieve the same results from other methods such as ignition, powerjet etc, so there was no point in pursuing. Think it was Doohan bike they tried it on, he came back saying dont bother.

[TZ350]

Your photo gives away that your injecting something direct into the cases, do tell.

234647

No, not injecting, that is/was the take off for a pumper carb,

I used the pump part to scavenge the plenum. I will keep the fitting there just in case I try a full blown pumper slide carb from a kart in the future.

234648

The clear cover was suggested to me by someone so I could see what was going on and Yow Ling suggested trying the straight shot carb idea just to see if that helped reduce fuel/oil drop out and/or increase power.

234649

I had been working on the plenum idea with its 32mm throat as a way of getting around the restriction of the 24mm carb rule. But 24mm has proved to be not as restrictive as people, myself included, thought it was.

The plenum may still have other uses, I think it or a variant might be usefull in broadining the power spread. As I have figured out a way to make a variable inlet throat that can be changed from 22mm to 34mm with the IgniTech's power valve controler. It may also be possible to extend the idea to variying the closing point of the rotary valve.

234651

I will come back to it after I have finished playing with the 30rwhp side port barrel. At the moment its a peaky beast, I hope to get it useable with a bit more development.

[bucketracer]

currently the insert is in blank form, but that's the next step. :wait:

234617


We will be needing to do something like this too.

Did you make the insert or is it something that can be bought semi finished and you machine it to suit.

[Bert]

We will be needing to do something like this too.

Did you make the insert or is it something that can be bought semi finished and you machine it to suit.

Off the shelve (blank), I'll send you the details. I was/am going to use it to make a copy then there will be no argument between after-market and raceparts...

[TZ350]

Dont waste your time and energy re water.
Honda did it with full PWM solenoid control - it bumped up the bottom end really well, but the water mist in the pipe kept it cool for so long down the straights that the engine never really recovered in time to get the top end back.
Another expensive blind alley.

Yes, it may prove to be a blind alley, but I have all the parts and have had my heart set on trying it for so long that I just have too.

The issue with the motor staying cool and not recovering the top end could be a blessing in disguise. As it could be an easy way of making a top end motor suitable for Mt Welly where its more about drive out of the corners than top end.

Or thumb on the button for water and drivability up the infield hill at Taupo and then across the top with no button to let it dry out in time for the faster bits out the back and the front straight.

The plan is to do several all out runs on the dyno without water and several with to find the base lines and changeover point.

Then a few runs on the dyno with it changing over should tell us all we need to know.

[F5 Dave]

. . .
so this is what we started with, standard TZR head complete with crappy noise reducing squish (apparently), welding this was never really going to work out well:
234615

. . .

Weird, never seen anything like that.

But I don't buy it. There is no explosion to create noise, the noise is the gas entering or exiting the engine. When squish is occurring the combustion chamber is isolated from the ports. How can this reduce noise?

[TZ350]

Had a great day Sunday, riding a borrowd RG50. Those F5's are so much fun I have been inspired to get back into working on my own 50.

This attempt at improving my 50 has nothing to do with the fact that Will beat me in every race Sunday.

Reduced the angle of the case reed, cutaway the spigot and flowed the reed into the transfer ducts.

[F5 Dave]

I've gone flatter than that, look at an RG250 or RM.

Why have you flowed from the base of the reedblock into the transfer?

Tip. RG engines are canted forward in their chassis. Make sure you take account for this when working out what angle your carb will end up at unless using something like a NS400 super steep downdraft. I prefer to spot on a flat plate & bolt aspigot, like a GP125 one if 24mm carb, or there is a bigger one (maybe X7??) that will take a 28. Isn't much fun when the carb falls off a simple tube type.

[Gigglebutton]

Thanks for lending me one of your bikes on Sunday. Well impressed with the fat power spread. Keep up the good work.

Dazz

[TZ350]

Why have you flowed from the base of the reedblock into the transfer?

Thanks for the tips on the reed and carb.

235049 235048

The porting from the case reed to the transfers was an attempt to emulate these inlet side ports that go from inside the inlet to the transfer.

[Henk]

Had a great day Sunday, riding a borrowd RG50. Those F5's are so much fun I have been inspired to get back into working on my own 50.


Getting a loaner ride on Cullys' last month has me looking for one as well.
Then I borrowed it again Sunday and broke it, now I need one instead of wanting as I hate wrecking other peoples toys.

[F5 Dave]

Hmm, those barrels on the right seem familiar from somewhere (CPI like on my 500) (edit, not they're not, think they are Cub CPI rather than Cheetah, see pic). But obviously the reed blocks are somewhat different to the suzi setup.

[TZ350]

Gigglebutton running 3rd on his F5 RG50 in F4 and going for the Doctor trying to beat all the FXR150's.

http://www.youtube.com/watch?v=v1pT-Tt_yMs

And finishing with the classic Deck-Inspection.

[Rick 52]

Thats what I did !! Great pass from Conner...

[TZ350]

Crank re-balanced for 50% and machined for more clearance and subsequently increased crankcase volume, there are no other changes to the engine.

235138

Ran the small crank that has the 2mm (1mm is Std) clearance everywhere between the crank and cases, on the dyno tonight.

235139

Old crank, blue line, new big clearance crank red line, poped a head gasket on the 3rd run.

Not looking promising at this stage, a few horses awol but at least the vibration has pretty much gone.

Ran out of time to fix it and play with the ignition and jetting, tommorow night hopefully.

[kel]

Gigglebutton running 3rd on his F5 RG50 in F4 and going for the Doctor trying to beat all the FXR150's.

Great little vid. Giggles 50 just keeps getting quicker!

[TZ350]

On page 200 there is a simpler 23 rwhp setup using a RG250 chamber modified to RM125 specs.

And on this page, the basic details for 27rwhp from a 1978 Suzuki GP125 Engine and RS125 Expansion Chamber.

235170

Not at all peaky, 3.500 rpm power spread.

Cylinder Deck Height (Squish) 0.8mm.
Exhaust 25.8mm from top of cylinder, and opens 80deg ATDC for 200deg Duration.
Transfers 40.8mm from top of cylinder, and open 116deg ATDC for 128deg Duration.
Inlet port opens 145 BTDC closes 80 ATDC and is 45deg wide and inlet port opened to 30mm equivelent dia with 24mm carb.
Std 1990 Honda RS125 Pipe. The pipe is 40mm and the exhaust port is 36mm, we leave it as is and don't match the Ex port to the pipe.

235176

Opening the rear transfers and flatening the port roof to 5 deg. Main std at 12 deg. Boost std at 55 deg, but all opening together.

235175

Primary transfer pretty much std., secondrys and boost as wide as possible, Exhaust 72% of bore diameter.

235172

A view of the transfers, the copper is to take heat from the exhaust port area and distribute it to the extra copper under cylinder finning we use.

235174

Dimensions of a Honda RS125 Pipe.

235171

Suzuki GP125 engine and RS pipe in a Yamaha FZR 3LN 250 rolling chassis.

And for somethig different, Rick doing the classic deck inspection. http://www.flickr.com/photos/dty1/5541562149/sizes/o/in/set-72157626304686340/

[ac3_snow]

good thing (or not) that the video didn't last any longer I did a bit of track side gardening about two laps later :corn:

[wobbly]

The cylinder pic is a CPI Cheetah Dave, the reed blocks are CR250, the Cub has smaller standard Banshee type reed bolt pattern.
I have just got the worlds first 3 CPI Cheetah cylinders with 66mm bore to run 400cc in the new F3 Superlight class, dead cool with more
power than the 485 will be absolute missiles.

[F5 Dave]

Yeah, looked like a monoblock, but then I edited when I saw the 4 bolt hole reedblock & guessed they were cubs. (The pic I posted is from my 496).

I read in CMM that Stan Stevens was building a 610 & it was supposed to have bigger reedblocks (CR500) but the ones they supplied didn't even fit.

The 400 idea is cool, have you got many takers for engines?

[wobbly]

I am building one into the prototype RS250 Aprilia racebike I have, and am building another complete Aprilia bike for a guy in Wellington.
The other cylinder is for sale - as part of an engine kit, once I have done the R&D, on reeds,pipes,ignition, PV curve etc.

[F5 Dave]

kewl. should shake up F3 a bit, look forward to seeing it in action.


. . . not that I make it to many race meetings these days.

[wobbly]

Sorry - yes the original pic was a Cub, I thought you had reposted the same pic.

[TZ350]

The popped head gasket from last nights dyno runs. I have been experimenting with using a head gasket to thermaly isolate the head from the barrel. With the copper fin and head gasket the head runs about 50-60 deg C while the cylinder is 90-100 after a good session on the dyno.

[Gigglebutton]

Great little vid. Giggles 50 just keeps getting quicker!

Cheer's Kelly. I had forgotten how much fun it is. The racing is way faster now, so it,s taking a while to get up to speed. I am going to pull the motor down and try to get a bit more power out of it before the next meeting and play with handling a bit more. Here's hopping :yes:

[wobbly]

I would suggest a couple of easily implemented changes to the 27Hp GP125 setup.
Fill the outer wall of the main transfer duct, to about the same radius as the secondary.
This would about 1/2 the entry area.Fill the case to match this new outer wall angle.
Drop the cylinder 0.5mm.Lift the front transfer and the exhaust back to where they were.
Fill the main transfer roof with epoxy such that there is none at the port exit, but change the roof angle to around 25*.
This would mean you have epoxy on the roof to the end of the outer turn, then epoxy starting to fill the outer wall from the same point at the beginning of the outer turn.
This directs the main port flow up and over the secondary transfers - the slightly reduced area due to the increased angle is more than offset by the better scavenging flow pattern in the "loop".
I would run this setup, then cut the valve to 85* closing.

[TZ350]

Fill the outer wall of the main transfer duct, to about the same radius as the secondary.
This would about 1/2 the entry area.Fill the case to match this new outer wall angle.

Ok.......... this was the 30 rwhp engine until I machined the crank down for more clearance (and more power). I can easily implement the other suggestions and if the idea is to reduce entry area of the main transfers.

Then could I build up the inner wall of the mains instead and make the divider wide like the Aprila RSA.

This would be easier for me than taking the cases apart again and it would mean the other cylinders would still fit the cases.

[wobbly]

I did wonder about the effect of the crank machining on the CCR,its the old story,make a change to affect a particular element in the design and the follow on effects on other elements may have greater impact on the power produced.
But either way you fill the transfer ducts, this will raise the CCR, and the roof angle change ,along with the port stagger,will give much better scavenging efficiency.

[TZ350]

I did wonder about the effect of the crank machining on the CCR....

Yes, I still think the crank has potential. I will try modifying the transfers with a bit of Devcon and see what happens.

If the crank clearance has to be closed up again, I can modify the transfer entrys and glue the cases to suit the smaller flywheels and get even more CC compression.....:D

[bucketracer]

A quick calculation and machining the cranks looks like it may have added 50-55cc to the crankcase volume, losing 3 or more ponies seems a big effect for just 50 cc's.