ESE's works engine tuner [Archive] - Page 4

SS90

6th April 2009, 20:19

I am going to have to formulate an action plan. One of the problems I have is working out how to get a main port that is angled up at 10 degrees to 65 degrees. I can't just file away at the port, it still has to retain its timing.

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Yea, I understand 100% on this one, it can be frustrating!

Just as an idea, could you CAREFULLY dremel out the cylinder area of the port (much more than you need to), and simply rebuild it (with Devcon) to the angle (and timing height) that you need.

It is something that I do, and have had success with, but only with rear auxillery window fed transfers, and some rear boost ports..... I have never tried it with main transfers....... I looked at using Devcon to build a "kicker" in a transfer port once, but was advised against it, as it was suggested that the heat would be too much for the devcon..... I couldn't really see why, as it (Devcon) survives the temperatures in the boost port quite nicely!

But, if you where confident that it would "stay put" there is no reason why you couldn't build all your "scavenge patterns" out of Devcon.......

I have never done all ports like that, but I have done boost ports and rear auxillery transfers!

Of course, as has been pointed out by Speedpro...... Devcon seems to work in everything EXCEPT the exhaust port!

SS90

7th April 2009, 03:39

Barrel Pic's.

Pic's 3 & 4 show an early 70's TM barrel with the traditional "Two" transfers.

Pic's 1 & 2 show a brand new late 70's GP125 barrel with rear gully port and two secondry ports.

The GP's secondrys look like after thoughts when you look at the ugly way they have been siamesed into the main transfer port ducts, pic-2.

I was thinking of opening these up and adding dividers between the mains and secondrys.

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OK, I rotated the picture of your boost port set up which makes it easier for me too see.

I read back at what both you and Saxet have said in regards to "the secondary transfers being an after thought", and now that I see them (and with a little time looking at the set up) I would think that it's actually a very well thought out concept..... BUT only for low R.P.M!

I believe that because of the close arrangement of the boost/transfer secondaries, Particularly at high RPM, you will get a degree of "short circuiting", of the transfer/boost port streams, whereas, in the low RPM the gains made from more complete cylinder scavenging ( via the high placed boost port hole in the piston) compensates for this loss.

I see from your posts that the boost port is originally at 55 deg.....

Now.... this is only theory, but , if I am right, (and at high RPM, the close arrangement is causing short circuiting),what about the idea of simply increasing the width of the boost port (top and bottom), so that it feeds into the secondary transfers the whole time?, and also, increase the size of the "BOOST PORT" hole in the piston, and effectively turning it from a "boost port", into a 5th transfer...... Kind of like a "scavenging transfer"........

As a suggestion, perhaps it would be a good idea to go to the effort of building a perspex "case" you could feed either water or coloured smoke, and if you put the piston in the cylinder at BDC, and used such a device you could better asscertain if you are indeed getting "short circuiting".

As another thought, if that is the case, could you just use the boost port as a "sacrifice", direct it straight across the bore, (at the exhaust port), and use it (this sacrificial stream) to "curtain" the primary and secondary transfer streams.........

That is quite an easy thing to try, and, with devcon is reversable if it brings poor results......

I would certainly be putting a divider between the primary and secondaries...with out hesitation...... of course you cannot (easily) put a divider from the bottom of the liner, and all the way up, as nice as it would be, and really are limited to just at the port edge (perhaps made from devcon), but what about cutting a hole from the out side of the outer wall the side of the cylinder (in line with the transfer port edge), and simply making an aluminium "plug" to fit in, that has a divider included, and simply welding it place... that way it would be easier to ensure you had the angle of the dividers the same, as if you make them from devcon, in place, they never will be the same angle, no matter how hard you try!

And, as such, you would not get any gains (because the streams are mismatched), and it would all be for nowt!

And you remove the risk of them failing (if they where made from devcon)

The important thing to remember about this level of porting is that there is not so much chance of "making a lemon" (as is the case of exhaust port height etc),

BUT..... if you get the transfer flows (scavenge patterns) uneven, or pointing a few degrees the wrong way, it's not so much that you loose power ( peak power is more or less the same compared to before you did the mods), it's more common to loose low RPM torque, and make a more narrow power band...

This is why many people find out about this tuning, then try it, unwittingly make a mistake/miscalculation, and, when they test it, it feels "almost the same", or "a little bit less" then, claim that "it's all rubbish", just because they didn't know what they where doing.

But, if you get it right, as you are now aware, the gains are quite amazing........

I personally believe there is tremendous gains in this "boost port/secondary transfer" set up....

My opinion is that to make measurable power gains in a two stroke (at least initially) you need to increase the strength of the power stroke, (other things like lighter flywheels, better ignitions, expensive carbs etc are, in my opinion secondary....) this can be done (as you are aware) with high cylinder compressions (among other methods), but also can be done by ensuring "more complete cylinder filling", which, if you achieve this via modern scavenge patterns, you not only fill the cylinder more, but also stop more fuel heading out the exhaust (using transfer/boost port streams to achieve this is one way).

This is why modern two stroke chamber design is so different that years gone by..... there is less need for the chamber to "suck" fuel back into the cylinder, as less fuel is wasted than in times before......

This (more effective cylinder scavenging) has enabled pipe designers to build and develop pipes with a bigger spread of power.

Modern cylinders are very sensitive to pipe changes..... older stuff (with older porting), less so.

On the point of cylinder filling, while it is not really an option to have a complete transfer divider.... I can recommend also having some aluminium added to the crankcase section of your transfers, and adding a " stream divider" at that end..... while you won't have a divider all the way up, you will get an advantage by having a divider for the streams when they leave the case to head up the cylinder liner, as well as having a divider before they enter the combustion chamber..... Don't make it symetrical though..... your scavenge pattern starts HERE, and should have the same angles at the bottom, as they do in the top.....

SS90

7th April 2009, 05:03

I just had a thought......

You use a "flat top" piston (with a small "dish" if I remember correctly)...... With such a piston, an angle of 55 deg on the boost port is VERY wrong, well, it is wrong in so much as with a flat piston...... with out the convexity of a "standard" piston 55 deg is simply too low.........

Looking at your figures of port angles (axial) 55 deg boost, 40 deg Secondary is where I would have started....... but with a flat top piston....yea........ummm..... I think "substantually higher" would be the order of the day (for both the boost and the secondary transfers, but the boost more so than the secondary transfers)...

Lacking the convex piston crown is a "good news/bad news" situation, and unfortunatly, in my opinion, you would not be able to take any modern engines as an example.......

However, the advantages of a flat top piston allow you to use a "kicker" in the boost port..........

You really need to point that "boost stream" straight up into the head (because of the flat piston crown).... what about raising the height of the boost port....say 2mm, and increase it's depth into the liner, and THEN putting a "kicker" (made from devcon) into the top of the boost port...... Hopefully, if the kicker is aimed correctly, you may see benifit from the "dish" in the piston......

It (the dish) may well cause a situation where the boost flow will "shield" the primary and secondary transfer streams from the exhaust, as the "boost stream" deflects from the combustion chamber, (and if all is aimed correctly) into the dish............. , and in doing so, the boost stream crates it's own "loop"

A little bit like combing a "cross flow" cylinder scavenge system, and a "closed loop" scavenge system......

Of course, for this to work, the angles of your secondary transfers will have to be very well thought out......certainly a few degrees lower than the boost... if not, short circuiting for certain!

Instead of using a kicker on the piston (like a cross flow cylinder scavenge system) to stop the transfer flows going out the exhaust port.....use the boost stream to achieve the same job.......

That would also stop any "short circuiting" of the secondary transfer/ boost streams as well (if that is happening).....

You may also have to run your cylinder compression a little lower though.....(and a slightly narrower squish area) but I don't think it will cause a power loss if you do.....

F5 Dave

7th April 2009, 09:46

SS90

7th April 2009, 10:25

Gee TZ you get a 25% power increase & you are still quibbling? I think the next thing to do is ride the thing & see if the power characteristics suit the bike esp considering the 5 speed gearbox. Many people forget the whole package approach if there is a compromise like a gearbox. But with such a wide spread it likely will be a non issue. The thing should feel like a complete monster in comparison. Or you might find it feels mellow but just much faster. Often you have to retard things if revving considerably higher than std.

Amusing to think that the main gain after 50 pages of thread is that a few runs on the dyno with an experienced operator has netted such a gain & pointed to your 'heat' issues. Over advanced is obviously bad, but well over rich will fade power as it gets hot.

f5, you are not wrong in your observations..... and all the things you have just pointed out have been said (like you point out..... pages and pages ago!)

But, I can't help but think what sort of curve he would end up with, when he applies even SOME of the things we have written about...... With such low primary compression,standard (old school) scavenge patterns... Shrouded transfer areas.... changing these things will not overly increase peak power, but will certainly give it a much longer power curve (make it less peaky), and more low end torque.... and some observers will also undoubtedly be keen to try some of these concepts on their own engines........ worth 50 pages I think!

From his curves, I would say it would indeed feel "mellow, but much faster", I think compared to the last time he rode it it will be much easier to ride, and therefore his lap times would drop considerably!

It's a common mistake to make.....you make a set up change (that makes the bike more peaky, but less power), and because the power "comes in such a rush", it feels like a monster, when infact it's slower!

F5 Dave

7th April 2009, 13:09

Yeah I have a special sneer for the 'now it wheelies changing into 3rd' crowd. Which can range from I've put a big pilot jet in which bogs till it clears out to I've changed the handlebars.

My H used to do the most ridiculous wheelies (high bars, supercross design pipe where I went a bit far on the diffuser). One round I spent the day on a carpark track perfecting my stand up wheelies. With a leakdown tester I found some issues & fixed them. It was far more effective.

But I have never been able to wheelie like that since. A part of me considered introducing that reedblock leak again:laugh:

Buckets4Me

7th April 2009, 13:51

Yeah I have a special sneer for the 'now it wheelies changing into 3rd' crowd. Which can range from I've put a big pilot jet in which bogs till it clears out to I've changed the handlebars.

:

it wheelies in 4 :blink: :innocent: :laugh:

nothing big and nasty unless you dump the clutch but just lifts the wheel up and carries it for a bit

TZ350

7th April 2009, 16:44

Yeah I have a special sneer for the 'now it wheelies changing into 3rd' crowd. :laugh:

I am pleased to have found a few extra ponies, let me count them 1, 2, 3.....19.5 and Ohhhh F5 by the way, did I mention that it now wheelies in 4th. :bleh: see you at Taupo.

F5 Dave

7th April 2009, 17:03

TZ350

7th April 2009, 19:00

Well maybe I'll bring my F4 bike this time to make it a fair fight.:soon: Actually I'll have my hands full this year so we'll see what happens.

Or I'll move the seat right over the rear wheel & it'll wheelie in 6th. No amount of power will make your bike do that. :laugh:

"A Fair Fight" I never said you were allowed to make it a fair fight! I need all the advantage I can get. :girlfight:

Wheelie in 6th now your being cruel!!!! :D

I am not 100% sure how this inertia dyno business works but I suspect that 19.5 RW-HP with short Mt Wellington gearing is not going to be 19.5 hp at the rear wheel on long Taupo gearing.

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speedpro

7th April 2009, 19:41

speedpro

7th April 2009, 19:44

TZ350

7th April 2009, 20:31

As I've found with the switch from old #6 to new #6, a lot of the wheelie potential of a machine is down to piss poor suspension. Old #6 would wheelie in 3rd if you changed direction fast enough and new #6 is reluctant to wheelie even doing all out drag starts.

Yes there are a few piss poor suspension problems with the bike. I am looking forward to getting on to them.

I have also heard of bikes tuned on the dyno expiring on the track, so I am a little worried about that.

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TZ350

7th April 2009, 20:36

I've only just put it all together with this talk of Taupo. It just shows you the sad state of bucket racing currently that a 14hp bike came third in the GP on a big track. You should have been getting lapped every 8 laps or so by a dozen 20+hp buckets fighting for 1st. No offence intended, just an observation.

Yes I know, 14hp comining :third: in the GP, how sads that. But I did lean forward going down the hills :scooter: and I am sure that helped a bit.

Also F5 Dave kindly waited for me on the straight bits so I wouldn’t feel left behind and lonely, thanks F5. :love:

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Sully60

7th April 2009, 20:36

As I've found with the switch from old #6 to new #6, a lot of the wheelie potential of a machine is down to piss poor suspension. Old #6 would wheelie in 3rd if you changed direction fast enough and new #6 is reluctant to wheelie even doing all out drag starts.

I suspect that's more to do with weight distribution than suspension. Even my slow RG 50 will understeer from the apex when the throttle is cracked, fun times! Add more pwer and it would get rool fun!

koba

7th April 2009, 21:33

I suspect that's more to do with weight distribution than suspension. Even my slow RG 50 will understeer from the apex when the throttle is cracked, fun times! Add more pwer and it would get rool fun!

I've notice the older bikes have thier weight alot further back, the rear brake is actually usable on the A100.

SS90

8th April 2009, 04:51

I have also heard of bikes tuned on the dyno expiring on the track, so I am a little worried about that.

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Ermm, smaller main jet aside....(you should be jetting for each day anyway), the only other significant changes you made involved retarding the ignition timing...... do you really think that this will cause the bike to expire Teezee???????

I personally would just go up 2 main jet sizes, (particularly if the track is at a significantly lower altitude than the dyno was, or perhaps if it was a cloudy day.......)..... and see how it feels...........

All you did when you changed your jet size on the dyno, was jet correctly for the atmpspheric conditions, altitude, air pressure etc)

..... and then you where able to measure the power difference....

Unlike at the track......

Where a "peaky" engine, feels more powerful than it really is!

Wind the rear shock preload and compression damping (if you have it) up to "FULL"..... see what happens to your power delivery.........

WHEEEEEEEEEEELIIIIIIIIEEEEEEEEEE!

A 20 HP 125cc air cooled engine with a24 carb is pretty good in my opinion!
:scooter::scooter::scooter::scooter:

But...how many NM do you have?????????

TZ350

8th April 2009, 06:43

I personally would just go up 2 main jet sizes,

But...how many NM do you have?????????

Yes I guess thats one thing I have learned, that a "peaky" engine, feels more powerful than it really is! This was common with 70's TZ's.

I will take your advice on the jet sizes. NM? I am afraid the dyno didn't give that info, it only graphed RW-HP against Km/h or at least on the screen that the operator was using.

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Buckets4Me

8th April 2009, 06:46

I've only just put it all together with this talk of Taupo. It just shows you the sad state of bucket racing currently that a 14hp bike came third in the GP on a big track. You should have been getting lapped every 8 laps or so by a dozen 20+hp buckets fighting for 1st. No offence intended, just an observation.

:doh: whent they watching from the side lines
broken thum
broken engine
broken gearbox ????

all the big guys from auckland anyway :spanking:
and Dangerous

SS90

8th April 2009, 12:19

Yes I guess thats one thing I have learned, that a "peaky" engine, feels more powerful than it really is! This was common with 70's TZ's.

NM? I am afraid the dyno didn't give that info, it only graphed RW-HP against Km/h or at least on the screen that the operator was using.

.

Oh...O.K.....

No disrespect intended......

Unfortunately, (in my opinion), you need to find another dyno.

From what I have read in your postings, the dyno operator you used is "on the money"... and will be an invaluable asset to your team.

But...the dyno programme he is using will not give you the full information you need.......

In one of my first posting I gave the information you need (in regards to how to measure horsepower (OR PS).....

It is a very easy calculation....

F5 DAVE used a Dyno to measure the power on his Trinity cylindered RGV framed "widow maker"...

I suggest you use the same Dyno.....

Dyno Jets Are old...but.....the programmes they use are VERY reliable...it just depends on what altitude they are...the old ones (like any in NZ), don't have a correction factor for each run......they use the same correction factor for every run.....

SHIT

At the very least, they are able to measure both Torque VS RPM, & HP VS Road speed......

This is want you want Torque VS RPM

If the dyno you use does not have an RPM pick up.....don't use it......

The operator you used (from what you have posted) is quite good.... maybe you could team up with him, and F5 Dave, rent the dynojet that F5 used and spend a few hours on that.

YOU CANNOT MEASURE HORSEPOWER......IT'S JUST A CALCULATION.....YOU CAN ONLY MEASURE TORQUE.......

TORQUE IS EVERYTHING

F5 Dave

8th April 2009, 12:34

Other end of the country & limited access anyway. But there are dynos in Auckers.

TZ350

8th April 2009, 13:55

YOU CANNOT MEASURE HORSEPOWER......IT'S JUST A CALCULATION.....YOU CAN ONLY MEASURE TORQUE.......

TORQUE IS EVERYTHING

I agree. Torque is everything. F5 dave lives about 750K's away so thats not an option. Commercial setups cost to many $$$$$'s, for me anyway. The dyno we used is home made and mechanicaly very good. The software is a bit old now but still does a good job for what they use it for. John who owns and operates it would quite likely be open to a software upgrade if there was someone compitent, willing and interested in doing it.

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speedpro

8th April 2009, 20:09

SS90

8th April 2009, 20:22

John who owns and operates it would quite likely be open to a software upgrade if there was someone compitent, willing and interested in doing it.

.

Yea, all it needs is an software change/upgrade!

The roller itself is just a balanced "known" weight, with a reluctor counting how fast it is turning!

As you know, you just need to combine that calculation with the exact RPM of the engine...

Maybe if someone got in contact with Graham Harris in Christchurch, he may be able to do something.

He wrote a programme for his dyno (which was DOS based)

His programme didn't even have an inductive engine RPM pick up, all you do is get a "ratio" run, where you run the bike on the dyno at say 3000 RPM, in the gear you want to do the run on, and measure the roller speed at this point (3000 RPM in third normally), against the tacho...then divide the engine RPM by the roller speed to get you ratio...enter that ratio, and you have the "missing factor" for your torque ( and therefore horsepower) calculation.....

A clever programme will do that automatically.

The advantage with the road speed Vs HP is that you are able to do a "all gear run"......

With an RPM Vs Torque run, all gear runs are not possible!

I hope I don't offend anyone when I say that Road speed Vs Hp readings are ALWAYS about 10% optimistic

Graham Harris's certainly is an old programme.....but it is able to give all the data you need!

(but not road speed Vs Hp), only Torque Vs RPM....

Expensive programmes can do both!

I am lucky enough to use a €4000 programme, and I know people who have copied it...(the programme) unfortunatly it requires an expensive "data box" as it uses a correction factor for each run.

However, this following link is an English translation of a German guys work, take a read, and, while it is a little strange, (recording the sound of the exhaust you say SS90...... are you crazy) I have done comparitive runs for power against this system with the expensive dyno I use, and it was pretty damned close...

The software is free to down load.... as well as instructions on how to build it....

The programme also is able to pick up readings from inertia drum dyno's as well, so you could build the set up, and use the home guys roller.......

No, that's not me in the pictures......

I use a "high tech" dyno, but some clever people here played a part in this programme....... and they tell me it is quite good..... I have compared results with this system against the dyno I use....... it was pretty damned close!

http://land.heim.at/pampa/252319/tmt/gsf_dyno.html

koba

8th April 2009, 21:39

Jumping out of the current theme a bit here but has this been mentioned?

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

http://www.heatsink-guide.com/peltier.htm

I doubt it would be efficient to use on a motorcycle but its all kind of interesting.

OK, I just looked at how much power it needs, thats really not going to work!

TZ350

8th April 2009, 22:46

From SAE Paper:= http://www.sae.org/technical/papers/730186

The study concluded that squish velocity has a major effect on optimum ignition timing and rate of combustion pressure rise, with a lesser effect on power, ignition voltage, and spark duration.

.

SS90

9th April 2009, 07:01

Geez you guys talk shit.

Thanks Speedpro... that's very nice of you to say!

Because you are such an expert on Dyno's (and I of course don't know my arse from my elbow)... I guess you would know

Can you explain why 1) the dyno Teezee used is unable to display a torque reading....... 2) how he could go about getting that data, and 3) why it is so important to graph your torque curve

I would attempt to do so, but what do I know!:drool:

craisin

9th April 2009, 07:23

sometimes a software update would require a hardware update:innocent:
eg more modern software may require XP and 400mhz CPU is minimum spec for XP.
Windows XP is a bit like your bike as if it is installed on a PC and you overclock it by putting a bigger CPU on the motherboard it has a tendency to crash and you need a fresh install.
Linux is free to download but you are better to download it on a linux machine and write it to disc and you install it with a network cable plugged into a Broadband connection.
they say you can configure linux to run on dial-up after the install but we failed on a mates machine as its a hassle.
I dont want to get involved doing software updates though

Pudding

9th April 2009, 08:31

Torque? horsepower? The only difference is a bit of maths.

“No Shit” Speedpro, :rolleyes: torque and horsepower are different things. Torque and RPM are physical quantities, horsepower is a combination of physical quantities and is therefore a mathematical construct.

Geez you guys talk shit.

Talk is a social construct and a psychological construct for example, is the concept of

“Looking in the Mirror” where one attributes to others a failing in themselves like “Talking Shit”. :laugh:

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bucketracer

9th April 2009, 10:38

Geez you guys talk shit. Torque? horsepower? The only difference is a bit of maths. If on the day you increased hp at ???rpm or ??mph then the torque increased at ???rpm or ??mph. You achieved an increase. Does it matter if the increase is measured in horsepower or torque. At the track it most certainly won't matter.

I agree with speedpro about "Does it matter if the increase is measured in horsepower or torque." And Pudding about the "Mirror".

Commentators, unless they are more socially sophisticated than most, call other peoples ideas shit, if they can't understand it themselves.

TZ knows the value of basic data. Given Torque/RPM he can model his current engine in his MOTA programe and based on his new understanding of modern port layout, make some informed guesses about the likely outcome of any modifications.

Just like Wobbly does.

Some of us just buy our technology/port layouts, like you and I have. But TZ is working it out for himself, inefficent, but he is doing it himself.

.

F5 Dave

9th April 2009, 10:43

Fooman

9th April 2009, 10:54

Torque and RPM are physical quantities, horsepower is a combination of physical quantities and is therefore a mathematical construct.
.

Not really. Think of power as "rate of applied force" or "rate of applied torque" - energy per second. It is no more a mathematical construct than velocity, which is the "rate of distance", or acceleration, which is the "rate of velocity" - or even RPM - which is the rate of turning, in units of revolutions per minute!

For linear motion (pushing something along):

Energy = Force x Distance (SI units = Newton x metres = Joules)

Velocity = Distance / Time (SI units = metres / second)

Power = Force x Velocity (SI units = Newton x metres / second = Joules / second = Watts)

For Rotational motion (i.e. a crankshaft spinning around):

Energy = Torque x angular distance (SI units: Newton metres x radians = Joules) (note: there are 2 pi radians in 360°)

Angular Velocity = Angular Distance / Time (SI units = radians / second)

Power = Torque x Velocity (SI units = Newton metres * radians / second = Joules / second = Watts)

or simply P = wT (w = lower case "omega" = angular velocity)

so, T = P/w

To get torque, divide the power by the angular speed (using whatever units you want).

With respect to engines, a power curve is simply the torque curve multiplied by the rotational velocity.

And the torque curve is simply a quantitative measurement of the relative efficiency of that particular engine, with respect to the speed of the engine (i.e. the rate of turning). The higher the torque at a particular speed, the more efficient the engine is at that speed. And the the higher the speed the engine can go for a certain torque, the more power it will make, and the higher the rate of work it can supply.

To compare different engines, you need to take into account the different geometries (stroke, bore, rod length) which affects torque, as well as the actual combustion efficiencies. Using BMEP is halfway there - a measurement of combustion efficiency that is independent of displacement, but it still needs geometry to identify the actual forces/torques in any particular engine.

See http://www.kiwibiker.co.nz/forums/showthread.php?p=607445#post607445 for something similar.

Cheers,
FM

F5 Dave

9th April 2009, 11:35

Good old Foo. Steps in every 10 or so pages and with a few succinct statements makes the rest of our inane drivel look pretty sloppy. Hitcher would be proud.

TZ350

9th April 2009, 12:29

You achieved an increase. Does it matter if the increase is measured in horsepower or torque. At the track it most certainly won't matter.

I think we have lost sight of what Speedpro was saying. That the dyno is perfectly good enough for development work.

.

F5 Dave

9th April 2009, 13:47

SS90

9th April 2009, 17:35

Well deriving revs against the curve would be considerably more useful vs speed can change the curve, what looks good in one gear vs another. At least against revs the shape is a bit more conventional. However certainly better than nothing & case in point was worthwhile. A single run with a revs trace may 'calibrate' you a bit though, also an 'all gears run' may help plot how your engine works against your gearbox, ideally worst case gearing.

Yup, exactly!

Fooman is quite right in regards to what he is saying as well, and in his posts points out that there is more than one method of measuring the power of an engine.

What we are talking about (at this juncture) is the collection of relevant data, and when you have it, working out just what it all means!

This is what "sorts the men out from the boys" in engine development

Speedpro, what we are talking about here is the fact that the dyno teezee used did not have an inductive RPM pick up on the hardware, so that it can graph the engine RPM Vs torque

Furthermore, if you cannot graph that function, you are unable to get all the data you need....this is development "level 1"

Speedpro:
Geez you guys talk shit. Torque? horsepower? The only difference is a bit of maths. If on the day you increased hp at ???rpm or ??mph then the torque increased at ???rpm or ??mph. You achieved an increase. Does it matter if the increase is measured in horsepower or torque. At the track it most certainly won't matter.

"at the track it certainly won't matter"

Wot?

Are you saying that at the track it won't matter if you make more horsepower, or more torque ?????....... as you can't tell the difference?????

I'll make this REAL simple.

Horsepower wins 1/4 miles,

[SIZE="3"]Torque wins hill climbs........

If you are building (developing an engine) you need to graph BOTH these.............

SS90

9th April 2009, 17:41

I think we have lost sight of what Speedpro was saying. That the dyno is perfectly good enough for development work.

.

I'm not knocking the dyno Teezee, yes, you certainly can use it for development work, no argument.

But, perhaps if you could get a torque curve, and starting working on the improvement of that....you will see what I mean (particularly in the area of "drive out of corners"

Believe me, you will be willing to sacrifice 1 or 2 PS "at the top" for 1 NM "at the bottom", especially when you compare what each graph looks like, to "how it feels on the track"

No-one loose sight of what I am talking about there...it's not the "peak numbers" I am on about....it's the "spread of power" (the physical property of torque)......this is displayed in the shape of the curve.

Fooman

9th April 2009, 20:55

Horsepower wins 1/4 miles

Torque wins hill climbs

If you are building (developing an engine) you need to graph BOTH these.............

1. Horsepower plus Traction wins 1/4 miles

2. Torque will only win hill climbs if you are not allowed (or too lazy) to use a gear box. And if the hill climb is short, or twisty without long straights. Reason:

A slope is essentially equivalent to a headwind - a constant load (the opposing vector of the weight force parallel to the slope) required to be overcome by the engine.

The top speed of any vehicle is governed by a force/energy/power balance - in this case of bucket racer on a infinitely flat long track, the power of the motor (torque times angular velocity) is balanced by the power of the headwind (drag force times linear velocity) at the maximum velocity (noting that the drag force is a function of velocity as well, and completely ignoring friction other than aerodynamic drag).

In the case of a bucket racer on an infinitely long slope, the power balance is motor power = (drag force times linear velocity) PLUS (component of weight force times linear velocity) at the maximum velocity (completely ignoring friction other than aerodynamic drag) - max velocity will decrease

In a race, be it on the flat or on a slope, maximum velocity is governed by power (if aerodynamics and weight, for a slope, are the same).

Acceleration is governed by how much power is left over from the engines capacity to supply power, after drag etc, and then an inertia balance comes into play (i.e. acceleration when available power is greater than 0 and related to the mass being accelerated).

Now, the capacity to do work is important - something with twice the power has the capacity to do twice the work in the same amount of time, or the same amount of work in half the time. Going from the bottom of a hill to the top is a set amount of work.

Now is the time to acknowledge that max power (for max acceleration and max velocity, therefore min time to complete hill climb) is not available at all engine speeds in the real world (unless you are using an electric motor). Therefore gearboxes are used to approximate peak power supply (and therefore peak thrust) at the wheel at all velocities.

So, in a hill climb between, say two bucket racers, a low power/high torque bucket will only beat out high power/low torque bucket if the race is short (initial acceleration is higher for high torque) and if the high speed/low torque bucket cannot use the mechanical advantage of a gearbox to convert the high speed high power into a low speed high torque.

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

Cheers,
FM

Yow Ling

9th April 2009, 21:17

Buckets4Me

9th April 2009, 21:24

craisin

9th April 2009, 22:21

hey F5 the downloads i saw from the link SS90 posted one was for windows and one was for linux and as linux dont have their own DOS program I assumed they would need a hardware update to run windows or linux.
I can get my hands on to 2 old DOS PCs one an old guy wants to give me comes with a printer.
:laugh:PM me if your interested preference given to aucks

speedpro

9th April 2009, 23:01

oh, so what sort of hardware update would be required to run this DOS program he is talking about:whistle:

You'd definitely need the latest DOS emulator. Some sort of dual processor platform should be able to run it OK. Say 2Gb of RAM would help of course.

speedpro

9th April 2009, 23:36

When I was visiting Pete Sales with his waterbrake dyno it was just the peak power we measured/calculated. When I lived about 5 minutes away from Dynotech and Chris Sayles(?) with the Dynojet inertia dyno he had, sometimes we'd connect the rpm sensor sometimes not. It really didn't matter. You could see at a glance when doing comparisons where the improvements were. Apart from a few experimental engines which disappointed my engines have always had big fat power curves which could be seen on the charts whether they were torque or horsepower against road speed or rpm. The dyno at Henderson Yamaha was a very nice Dynojet eddy current model which was great as you could load up an engine and hold it at any speed and check what happened - whether it held power or faded off.
Anyone can disagree if they like but results talk.
If you achieve an increase in horsepower at a particular engine speed, or road speed in the same gear, then the torque has to have increased at that engine speed. After a lot of track time and lots of dyno runs you get a good feel for what makes a good trade. Torque in the mid range for a couple more horsepower up top or vice versa. Torque isn't everything. Harleys make lots of torque but your average 600 blows them away in a top gear roll-on at 100kmh. Kenworths make stupendous torque at 2,500rpm with 40lbs boost but it only comes out to say 300-350hp.
It doesn't matter what you measure or how, as long as the measurements are made in a consistent manner that allows you to identify improvements. Experience will tell you which improvements and where are best suited to your bike, you, and the track.

SS90

10th April 2009, 03:52

OK the Harris dyno graphing output thing isnt quite as flash as some remember
Heres the output of a reasonable four stroke bucket . I noticed that if you rotate it 90° in the clockwise direction it looks like a large nose. After running it on the dyno it was hard to tell if it was any faster. Am I missing something here?
Soon after I did this run I fitted race cams and bent the exhaust valves, is this normal?

Hmmm, do I detect a hint of sarcasm here Yowling?

Was it any faster after you ran it on the dyno? Well, did you asses the graphs,(you only posted the horsepower figure..... the program is able to plot (and print) both Horsepower and torque together, or (separately)

then, make changes to the set up ( like cam timing (or profile), ignition timing,exhaust pipe etc etc etc), based on what gains you where trying to achieve, or, just run it on the dyno "to see what it had"....

It not just a toy!:msn-wink:

Oh, when you fitted the new cam, did you measure the piston to valve clearance?, or ,just "wack it in, and hope for the best"

SS90

10th April 2009, 04:35

I think we have lost sight of what Speedpro was saying. That the dyno is perfectly good enough for development work.

.

Anyways....

So what is your next step Teezee? Obviously you have a much more powerful engine than before... when is the next race?

I guess logically you need to gauge what it feels like now, so a race meeting is the obvious choice!

On another (old) subject.... this is a piston that a company in Italy are now using..... I like the concept actually!

craisin

10th April 2009, 06:50

You'd definitely need the latest DOS emulator. Some sort of dual processor platform should be able to run it OK. Say 2Gb of RAM would help of course.thanks speedpro
heaps of RAM and processor speed is the answer to a lot of PC woes.
I could donate older hardware if anyone was keen ,but its not the way forward

TZ350

10th April 2009, 08:52

Anyways....

So what is your next step Teezee? Obviously you have a much more powerful engine than before... when is the next race?

I guess logically you need to gauge what it feels like now, so a race meeting is the obvious choice!

On another (old) subject.... this is a piston that a company in Italy are now using..... I like the concept actually!

Thanks for a look at the piston. I wouldn't have thought of flowing the transfers like that. I have a cylinder that needs reboring and an oversize 0.5mm Wiesco piston that looks like it can be cut away a bit. Out of interest the piston you have shown me, are they for sale? I use a 56mm piston with a 14 or 16mm pin?

Getting to run the bike again next Sunday (2 days time) at Kaitoki. Then there is a points race at Mt Wellington the following Sunday so I will know a whole lot more by then.

The Yamaha SAE paper and MOTA measure the way the transfer ports point to the rear of the cylinder differently. The SAE paper measures it tangentaly and is a whole lot easier to do than MOTA's radial approch.

Its taxing me a bit trying to make good measurements of the port angles, but getting there. And I am keen to see if I can get some good torque and revs dyno data sometime so I can model the engine in MOTA and have a good base to research the port/chamber mods before actually cutting metal.

I was impressed with Johns dyno, many good bikes have been developed there. Avalons Honda RS125 gets developed there and she is running at the front of the GP125 class this year. The idea of graphing Hp against road speed works well and is fantastic for setting up the gearing, totaly impressed and will be going there again (lots).

My current barrel ex opens 81 ATDC 71% bore width and the RM pipe are not the best match and I want to develop a barrel with more modern port shapes and timings, like ex opens 86 ATDC 68% bore width, trans open 116 ATDC, inlet 145/55 and 1.5 primery comp ratio to run with the RM or a more modern chamber.

.

SS90

10th April 2009, 13:10

Thanks for a look at the piston.

My current barrel ex opens 81 ATDC 71% bore width and the RM pipe are not the best match and I want to develop a barrel with more modern port shapes and timings, like ex opens 86 ATDC 68% bore width, trans open 116 ATDC, inlet 145/55 and 1.5 primery comp ratio to run with the RM or a more modern chamber.

.

I have emailed the company (fortunately they speak German) and asked for details about the piston.

Interesting about your timings.....86 Deg for the exhaust is pretty damn good!,and 116 for the transfers is about right too (in my opinion)....a very useable engine!, but you do realise that you will need to shorten your stinger length (considerably), as well as change the angle of your diffusers (both of them, as well as the length...) to make use of these timings..... right?....
Also, I could suggest a new header pipe as well..... (not being picky,just trying to help)

The exhaust width is a good idea, it will cost you torque, but will also reduce the temperature of the piston, so it's a fair exchange!

I have made an exhaust to the same specs as yours/ old school RM125 it was funny to calculate, compared to modern equations..... WOW!..... And next I am tuning a cylinder to the same specs as you have now as well.. (OK cast iron Polini, and it's 133cc's...and the inlet manifold has to be 134mm (can't change that), fortunately it does have a 24mm carb! But a customer is paying, as that is the only way I can do it), not perfect, but the closest I can do right now, and it will be interesting to see what I can get.... I assure you, the dyno I use will NOT read 19.5 PS......... it will be somewhat less...... we will see on that. My calculations are closer to 17PS......., but I believe it will have 15 NM....... Certainly not the best I can do (exhaust is a limiting factor, so is carb size, as is inlet manifold length as well.)

I will take a picture of the exhaust on saturday (tomorrow is a holiday...yay!) and post that (just for fun)

If you want some help with your exhaust, I am willing to lend a hand.

Nice work on the new port timings.....not "cutting edge", but not far off!

Oh yea....measuring port angles....... I feel your pain........I even made "moulds" from hot plastic once.........

SS90

10th April 2009, 13:30

thanks speedpro
heaps of RAM and processor speed is the answer to a lot of PC woes.
I could donate older hardware if anyone was keen ,but its not the way forward

Hi Craisin, How easy is it to write a dyno program???....... it's not really complicated mathematics, and there is already a roller needing a new program.... it just needs to be able to accept an RPM pick up, and you can do so much more!!

speedpro

10th April 2009, 19:30

thanks speedpro
heaps of RAM and processor speed is the answer to a lot of PC woes.
I could donate older hardware if anyone was keen ,but its not the way forward

My "piss taking" definitely needs work. It's DOS people!

An old 386 with 640Kb RAM will be fine. Any odd number version of DOS should be fine. I'm old, I can remember being impressed with my work 486 with 1.2Mb RAM.

If you are running one of those new "Windows" OSs just click Start - run, then enter "command". You are now in the world of DOS.

craisin

10th April 2009, 20:10

Hi Craisin, How easy is it to write a dyno program???....... it's not really complicated mathematics, and there is already a roller needing a new program.... it just needs to be able to accept an RPM pick up, and you can do so much more!!
Hi SS90 my path into computers began about 6 years ago when a friend gave me an old 386 running w95 It would break down quite often and a nephew said he would fix it if i would fix his car. In the end I was better in fixing PCs than my nephew
But what i didnt realise I had become a pirate as they say, so i bought a brand new PC to avoid being a pirate.
And i started using Linux on older PCs I have been given for helping people with their projects.
Ive taken the easy way and avoided using DOS as most people use young people as a way through computer programing to avoid red tape . :niceone:

craisin

10th April 2009, 20:52

My "piss taking" definitely needs work. It's DOS people!

An old 386 with 640Kb RAM will be fine. Any odd number version of DOS should be fine. I'm old, I can remember being impressed with my work 486 with 1.2Mb RAM.

If you are running one of those new "Windows" OSs just click Start - run, then enter "command". You are now in the world of DOS.

yeah right speedpro there are many way to skin a cat :niceone:but not ceiling cat cause he knows a lot about stroking and he doesnt let the secrets out

k14

11th April 2009, 09:59

If you are running one of those new "Windows" OSs just click Start - run, then enter "command". You are now in the world of DOS.
Not quite, if you have vista you have to do a bit of running around to get it to work. Also "cmd" works just as well and its faster :) You may have problems trying to run old dos programs in a 32 or 64 bit os though. May just be easier to get a 486 off trademe for $5.

TZ350

11th April 2009, 20:55

I have emailed the company (fortunately they speak German) and asked for details about the piston.

Interesting about your timings.....86 Deg for the exhaust is pretty damn good!,and 116 for the transfers is about right too (in my opinion)....a very useable engine!, but you do realise that you will need to shorten your stinger length (considerably), as well as change the angle of your diffusers (both of them, as well as the length...) to make use of these timings..... right?....
Also, I could suggest a new header pipe as well..... (not being picky,just trying to help) ...

Many thanks SS90 for looking into the piston.

I would be interested in your ideas. I am keen to plan then construct a new barrel/pipe combo for drive out of corners.

.

Sully60

11th April 2009, 21:02

Many thanks SS90. I would be interested in your ideas.

.

You better not still be home, you'll need to be fresh for your whooping tommorrow!:p

Buckets4Me

11th April 2009, 21:21

You better not still be home, you'll need to be fresh for your whooping tommorrow!:p

you'r getting him all excited:woohoo:

TZ350

11th April 2009, 21:27

You better not still be home, you'll need to be fresh for your whooping tommorrow!:p

Fawwwk what, not Tommorow?????? .....Help.... better get my skates on..........

.

Sully60

11th April 2009, 21:29

Fawwwk what, not Tommorow?????? .....Help.... better get my skates on..........

.

You'll need to keep them on all weekend;)

TZ350

11th April 2009, 21:33

You'll need to keep them on all weekend;)

Yea I recon. I have been up to look at the track. Can't wait.

.

TZ350

14th April 2009, 10:32

Well the dyno didn’t lie, the bike fair zipped along. But now I am living proof that having more Hp does not translate into more racing success. A big thankyou to the Welly’s for having us Auckers down to play, it was a great show and the best people you could wish to spend time with. It was great to catch up with riders I met at Taupo last year and I am looking forward to seeing them again this year.

Many thanks to Sully60 for taking the time to ride my bike and give me some pointers on improving its handling. I will follow his suggestions for Mt Wellington next weekend. It runs wide in the corners. Looking at the photos I can see my front wheel is turned out of the corner as if the bike is sliding when other bikes in the pic are turned into the corner.

Awesome day, awesome people, awesome track and an awesomely zippy bike, I am looking forward to Taupo where the copper kettle can realy stretch its leggs.

F5 Dave

14th April 2009, 10:38

Well good on ya & Pumba for making the trip. It is usually me traveling to the other side of the island to race Mt Wgtn. Please spread the word about the track. Kaitoke 2nd best Bucket track in NZ (after Blenheim I reckon).

Buckets4Me

14th April 2009, 19:33

TZ350

14th April 2009, 19:44

and the green gl145 powered nsr (cant remember your name sorry)

"Mark" has the very good looking green bike. He won some B grade races and was then bumped up to A grade.

.

Sully60

14th April 2009, 20:06

Big respect for making the trip down to TZ and the rest of the Auckland crew.
It was great to meet you guys.

The GP # 14 is a serious piece of kit alright, I was quite taken a back when I left the pits, got it up on the pipe and it wheelied in second and third gear, with the choke still on, ahem:innocent:

I did find the power delivery quite peaky, bearing in mind my bike has the flattest power delivery of any non FXR bike out there it was quite a struggle at first.

Once I got used to where the power was I started to enjoy it, the last bike I rode that I could wheelie out of the last left before the pit entrance was a Husky NOX so that tells me a few things.

Like we discussed after my session I think you need more preload on the rear and dial in some more dampening to deal with it, I'd try that first. Apart from the wheelies, the tendancy to not track a good line through the faster corners was quite a handicap, especially at Kaitoke where you need to carry momentum through that corner to make the most of all that lovely power up the hill. Maybe then if you think it could be better drop the forks though, I'd be a little reluctant to do that because the handling in the slower turns was really good, I found the bike worked really well in that regard coming down the hill when I wasn't trying to use all the power and just 'connecting' the turns together, it was nimble and quite accurate, I'd be worried that if you lowered it too far at the front it may get a bit 'pushy' in the slower turns.

I'm just thinking out loud a bit though, just try stuff out and see what works for you, though I would go as far as saying that you don't need to much more power, make the power you've got go in the direction you want the bike to go and you'll be disapearing in a sweet blue haze:bye:

TZ350

14th April 2009, 20:09

I will take a picture of the exhaust on saturday (tomorrow is a holiday...yay!) and post that (just for fun)

If you want some help with your exhaust, I am willing to lend a hand.

Nice work on the new port timings.....not "cutting edge", but not far off!.........

SS90 the bike ran well but suffered from the old school porting/narrow powerband. I would appreciate some help with a pipe and porting especially ideas about how much the transfers could angle up as I have not got my head fully around the new way of doing it.

Looking to broaden the powerband and make it more drivable.

It looks like we will be able to take one or two of the other Team ESE GP125 bikes to a Dyno on Thursday that can (hopefully) give us printouts of torque/reves. Mine will miss out as it is in transit back from Welly.

.

Pumba

14th April 2009, 20:16

Mine will miss out as it is in transit back from Welly.

It stopped being in transit a while ago. You know were it is if you want it.

nudemetalz

14th April 2009, 20:17

"Mark" has the very good looking green bike. He won some B grade races and was then bumped up to A grade.

.

...and he got awarded "Best Present Bucket" !!! :rockon:

Sheez, was watching Sully pushing the GP125 of TZ's around. Damn it could move !!!!!!!!!! :gob:

TZ350

14th April 2009, 21:10

It stopped being in transit a while ago. You know were it is if you want it.

Thanks Pumba for shipping my bike and sharing your pit setup with us. It made it a great day, thanks.

.

SS90

15th April 2009, 10:20

SS90 the bike ran well but suffered from the old school porting/narrow powerband. I would appreciate some help with a pipe and porting especially ideas about how much the transfers could angle up as I have not got my head fully around the new way of doing it.

Looking to broaden the powerband and make it more drivable.

It looks like we will be able to take one or two of the other Team ESE GP125 bikes to a Dyno on Thursday that can (hopefully) give us printouts of torque/reves. Mine will miss out as it is in transit back from Welly.

.

Sure, no problems,
I have attached a few pictures of the engine and exhaust I am doing at the moment.

As I said it's Polini 133cc's, cast iron cylinder, with port timings closer to where I believe you would end up to get a nice torquey bike.
The port layout is also very similar to yours (with the rear boost port/transfer layout, although, not so "crowded")

I will post all timings when I finish the project, as it is only just the beginning.

I modified an existing exhaust system (see pics) to closer (not perfectly) match the one you have.

The compression ratio etc will all change as I go, but I believe that it will be somewhere around 13.8:1, I also currently go against convention and do not use a "squish band" in my heads, and have not done for some time now.

I used to get critisised for this alot here (not any more), but stand by my experience when I say that while there are power gains in a squish band head, rideability (particularly partial throttle when cornering, and wider longer power curves) are possible with out a squish band....

I am also using an ignition system that I developed this winter (nothing special, It's just a "twist and go" ignition system modified to run on a small frame vespa, it just retards 8 DEG, (but original Vespa electronic ones ADVANCE 2 DEG, so you can see why I / we, went to the effort!

Rather than just "throw some angles and a pipe design" at you, it would be better to try and see if I am able to assist by finding some ideas that are applicable to your specific criteria (little carb etc)

I do believe I already have a pipe that would be what you are looking for, but I want to be sure first, and starting with this pipe (which is close to yours) would be a more scientific way (I think)

I added this to youtube today
http://www.youtube.com/watch?v=1DtPFWtrPJY

I will have it all ready tomorrow, but the customer is waiting to get his scooter from the painters next week, so I will have to wait till then to get it on the Dyno

Just as a thought (if you manage to get the bikes to a dyno that can read torque vs RPM, then you will know what you have now, but from your exhaust timings, I would suggest your torque is quite low, perhaps even 13 NM )

I could be wrong on that one though!

I believe that you could (with better exhaust and porting) get a really rideable bike with, say (just for a number) 18 PS, and 16 NM, with a VERY long power band.

It sounds like you are already making good power (after the dyno) and what sully60 said reaffirms what you expected you would find...... a little too peaky....... you have already mentioned that you are unlikely to make any more peak power (logically), and I think that you will sacrifice a little of that peak and make useable gains elsewhere (so much so that it will "feel" more powerful, but in fact make 1 or perhaps 2 Ps less, in return for that nice torquey long power curved engine you want!

That's my experience any way!

TZ350

15th April 2009, 22:36

I enjoyed the vid.

I believe that you could (with better exhaust and porting) get a really rideable bike with, say (just for a number) 18 PS, and 16 NM, with a VERY long power band.

This is where I would like to go.

.

TZ350

15th April 2009, 22:39

I think you need more preload on the rear and dial in some more dampening to deal with it, I'd try that first.

I will give this a go Sunday and let you know how it pans out. Many thanks.

.

TZ350

16th April 2009, 19:20

Dyno runs of another two Team ESE GP125’s, both engines are basically standard GP125’s with 1.75mm skimmed from the top of the barrel and “O” ringed, KX80 ignitions and running home made RM125 spec pipes. No other changes to the ports or inlet timing.

First runs for both were about 14Hp at 8,000/8500 rpm. The only changes were advancing the ignition timing to greater than the standard 20 BTDC and leaning the mains from 112.5 or so to around 105 (std is about 90-95).

1st pic max hp 16.5 @ 9,500rpm and max torque 9.75 ft-lbs @ 8,750rpm.

2nd pic max hp 18.3 @ 10,000rpm and max torque 10.4 ft-lbs @ 8,500rpm.

Interestingly the motor (second pic) with the original non-squish open hemisphere head made the most power, 18hp @ 10,000rpm and has a sharp peak @ 11,500rpm. Not sure why it has this peak, but have a few ideas as I have seen similar curves on MOTA and changes to the exhaust port width plumped the curve up just before the peak.

The bike in pic 1 has a squish head and high compression. I suspect its over compressed and that is why the power is dropping at the top end. I think that if we reduce the compression ratio of the first bike we will get more Hp and a graph more like the second pic.

Even more interesting is these bikes had to have their ignition timing advanced to the max limit allowed by the backing plate where mine had to be fully retarded and all three bikes run about the same (105, 107.5) main jet.

The difference between the red and green lines is 1 notch on the needle. These two bikes run the needle clip on the 3rd setting and mine with the big exhaust port runs on the 1st (top) setting with a 102.5 main jet and way retarded ignition for 19.5hp.

Look at that wide flat power band in pic 2. :2thumbsup

If SS90 can help us improve on that, there are going to be some FXR's in big, big trouble.

.

Buckets4Me

16th April 2009, 20:09

16.5 @ 9,500rpm and max torque 9.75 ft-lbs @ 8,750rpm.
17.5
18.3 @ 10,000rpm and max torque 10.4 ft-lbs @ 8,500rpm.
19.5
.

who is going to be first to 20 ???? :whistle:

can we measure the red and yellow bikes see ifwe can get 14 and 15 hp ????
the we would have a full house (or is it a flush) I always lost at gambling :pinch:

koba

16th April 2009, 20:23

Look at that wide flat power band in pic 2. :2thumbsup

.

:2thumbsup is right!

Ned Kelly

16th April 2009, 21:00

Well at least I am pulling 16+ HP now Carl. Started as a base line of about 13Hp. Nice crisp sound and plenty of torque. I will get down on Saturday and run some test laps. Cully is running the engine out of the red bike at the moment while he makes some bearing repairs on his engine. Looking forward to some fast laps on Sat/Sunday

Ned Kelly

16th April 2009, 21:01

Well at least I am pulling 16+ HP now Carl. Started as a base line of about 13
Nice crisp sound and plenty of torque. I will get down on Saturday and run some test laps. Cully is running the engine out of the red bike at the moment while make some bearing repairs on his engine. looking forward to some fast laps on Sat/Sunday:2thumbsup

Pumba

16th April 2009, 21:37

Well at least I am pulling 16+ HP now Carl. Started as a base line of about 13
Nice crisp sound and plenty of torque

Ahh shit, looks like I am in real trouble now:doh: the A grade mid pack just got real interesting. Time to take a concrete and throw it into the corners harder.

koba

16th April 2009, 22:19

The FXR is kind of like the benchmark bucket at the moment isn't it?
I seem to remember Richban reporting a dyno figure like 17.5hp (http://www.kiwibiker.co.nz/forums/showthread.php?p=1883608&highlight=dyno#post1883608)If thats correct it is quite alot to compete with.
(Ahh Found it and added link)

I never seemed to meet THE GP125 at Kaitoke at any point but judging by what others have said it was probably easily the fastest staight line bike there in the weekend. Quite alot faster than any FXR there.

Is all that because the GP makes beter tourque or somthing?
Tex on his GP 125 seemed to have heaps more effective power than I had on the overcarbed FXR I was on, yet I cant imagine it being much (if any) more powerful in peak power.

TZ350

17th April 2009, 10:12

saxet

17th April 2009, 11:58

I never seemed to meet THE GP125 at Kaitoke at any point but judging by what others have said it was probably easily the fastest staight line bike there in the weekend. Quite alot faster than any FXR there.

Is all that because the GP makes beter tourque or somthing?
Tex on his GP 125 seemed to have heaps more effective power than I had on the overcarbed FXR I was on, yet I cant imagine it being much (if any) more powerful in peak power.[/QUOTE]

I'd doubt mt GP125 has more power than an FXR, it,s a matter of being able to use it. TZ's GP would pull away from me on the straights even tho I'd got a much better run out of a corner, then I'd have to take him under braking. Track knowledge counts for alot.

F5 Dave

17th April 2009, 12:43

Bearing in mind differences in Dynos my understanding is an FXR std probably does 16hp with a wide spread. Makes sense that Rich's mildly tuned FXR does 17.5. When the guy put the GN or whatever carb on yours the chance that he put the right jet in it is slim.

So a decent GP with nigh on 20hp & a decent spread should be an easy match for an FXR. The news that the bikes in wgtn aren't highly developed is pretty old. A decent rider on a ok handling bike with some good power can do the buss. I'm not saying I fall into that category but when I had the H I used to regularly just walk away from the field with 18hp & it was quick turning but not particularly pretty handling. I think if you put that old engine in a decent frame with a good rider he should do the same. - Oh look, Glen did just that & on his first outing was right up there. He'll go further with some more time on it.

The FXRs are a great starting bike, but the GP should have more potential, or at least equivalent.

Buckets4Me

17th April 2009, 13:21

The FXRs are a great starting bike, but the GP should have more potential, or at least equivalent.

the GP Sux when you compair them standard
17 wheels ???? dont think so
brakes what brakes
the frame is made from noodle straws and bungie cords

as a standard bike the fxr is just soooo much better
but it's booring :yawn:

the gp needs to have 17" rims stiched on to it (not to hard)
and slight mods to the engine

then you have got 17 hp (or there abouts)
and a bike that handles like shite and has no brakes :wacko:
:2thumbsup

just like all the fast guys back in the 80's :eek5:

put the gp into another frame ;) now that is potential say 17.5 hp (19.5 maby) in an rs

dan then it shows up how bad I ride crybaby:

I think I'm just going to ride the rg50 this year :hug:

F5 Dave

17th April 2009, 14:25

for sure the GPs handle terribly std. Gyro had a very fast watercooled 100 back in the day. Felt like the front end wasn't connected though. Yes the RG50 handles great in comparison, much fun to ride & teaches you to peddle faster to keep up with the bigger bikes or in Auckland you aren't short of 50 competition (as we were very strong in 50 class when Jay & Hamish were riding & Fishe & Chris Sales before that. Miss those days).

SS90

17th April 2009, 18:11

Interestingly the motor (second pic) with the original non-squish open hemisphere head made the most power, 18hp @ 10,000rpm and has a sharp peak @ 11,500rpm. Not sure why it has this peak, but have a few ideas as I have seen similar curves on MOTA and changes to the exhaust port width plumped the curve up just before the peak.

The bike in pic 1 has a squish head and high compression. I suspect its over compressed and that is why the power is dropping at the top end. I think that if we reduce the compression ratio of the first bike we will get more Hp and a graph more like the second pic.

.

Yea, that's the interesting thing about cylinder heads and compression set ups, particularly with gear box ratios that are unsuited to racing (GP125's,ax100's small frame Vespa's etc)

So many people (previously myself included) forget about the fact that to "copy" alot of two stroke performance stuff from racing circles is not always applicable, due to the fact on the sort of machines we use for tuning, because of the gear box ratios, require long wide power bands, where as "real" race stuff normally has 6 closely spaced gears, enabling larger exhaust port areas (for one thing) that will give you heaps more peak power (at the expense of torque).

A good example of an excellent bucket tuning motor (as we all know) is an MB100, not only for the fact that it is crankcase induction (a clear advantage), but almost as importantly, you can fit the MB50 gearbox (6 speed), and not only are you able to make good power with these engines, but you are also, with the 6 speed close ratio gearbox, able to "keep the engine in the power"..if you had a well tuned 22 P.S MB100 with an original 5 speed gear box, I suspect you would have trouble when you went from 4th to 5th gear......

But that has been covered a few times!

Interesting about the curve shape and the compression ratios/squish head.

Your thoughts (in my experience) are correct in regards to high comp (over compressed), and short "peaky" curves.

For street tuned engines, I run about 13.6:1 and actually don't use squish heads at all anymore, as I found that since I never really exceeded that ratio, a squish head was not required,(as there is little chance of detonation at this level) as well as that fact that even with lower ratios than 13.6:1 squish heads, while if used with higher compressions will produce more peak power (at the expense of power width) with lower ratios the power was the same peak, but narrower that with out.....

Basically, with a ratio of around 13.6:1, you have alot more "over-rev", and, in this situation, that is what you want to achieve!

Honestly, the curves you just posted are not bad at all (really) and personally, I believe that you can achieve something like 17 NM of torque (12.5 FT/LB) and 19 P.S with a GP125 engine, while making power for approx 2000 RPM.

Much more suitable for a 5 speed box!

Before you want to change your pipe design, if it is possible, can you make the changes to your primary compression that you discussed, get a standard (oringed) head, with compression ratio as I mentioned, and run that on the dyno.....

For the pipe design, this would be a really good reference for me!

Also, I while back (first few posts) I mentioned about exhaust port and transfer timings of 188 deg and 131 deg (respectively), which you pointed out where the same as a tuned RM125 (I think)

I really believe that this is more suitable for what you are doing....

F5 Dave

17th April 2009, 18:38

MB is actually 4 speed std, although you can fit the MT50 5 speed (or MB50 6 speed).

Sketchy_Racer

17th April 2009, 18:47

TZ350

17th April 2009, 20:08

Before you want to change your pipe design, if it is possible, can you make the changes to your primary compression that you discussed, get a standard (oringed) head, with compression ratio as I mentioned, and run that on the dyno.....

For the pipe design, this would be a really good reference for me!

The 2nd pic max hp 18.3 @ 10,000rpm and max torque 10.4 ft-lbs @ 8,500rpm. Bike belongs to Chambers, and the motor is basically a standard GP125 with a bit trimed of the top of the cylinder and fitted with a RM spec pipe.

This is more the spec motor I want. Working from memary here, (my notes are at work), Specs are:-

1.75mm machined from the top of a std cylinder. "O" ringed, Ex opens 86 ATDC, 64% of Bore Width, which is std, Trans 114 ATDC, Std Inlet Opens 145 BTDC Closes 55 ATDC,

Std Head, no head gasket, Compresion ratio 7:1 with No Squish, Primary compresion 1.45:1, KX80 ignition, Ignition timing at a guess 24-26 BTDC with no auto retard, GP125 24mm carb with modified bell mouth and 105 main jet,

RM spec pipe. Max hp 18.3 @ 10,000rpm and max torque 10.4 ft-lbs @ 8,500rpm. A wide flat power curve with a little peak at the end. A similar motor with a RG250 pipe made 17Hp.

.

TZ350

17th April 2009, 20:31

Honestly, the curves you just posted are not bad at all (really) and personally, I believe that you can achieve something like 17 NM of torque (12.5 FT/LB) and 19 P.S with a GP125 engine, while making power for approx 2000 RPM.

Much more suitable for a 5 speed box!....

A Handy Coverter:- http://www.mr2ownersclub.com/converter.htm

Yes your right, we have about 18-19 Ps and 14 Nm now (1 ft lb = 1.356 Nm ...) so 17 Nm would make this bike very drivable.

Pic 1 is Chambers GP125 and Pic 2 is a Dyno graph of the RM125 from Graham Bells book. 22.6 Hp @ 10500 Rpm and 12.3 Ft-Lb at 9,500 Rpm. 1000 Rpm between peaks.

This will be my aim 19 or so Hp and 12.5 ft/lb (now 10.5 ft/lb) with 2000 Rpm between peaks. The old trade off, sacrifice a bit of Hp for more torque and a broader power band.

So the problem is more about increasing the torque than making more Hp.

How can we use the new style of porting to increase the torque? SS90 do you have any suggestions?

.

Rick 52

17th April 2009, 22:39

the GP Sux when you compair them standard
put the gp into another frame ;) now that is potential say 17.5 hp (19.5 maby) in an rs

dan then it shows up how bad I ride crybaby:

I think I'm just going to ride the rg50 this year :hug:

Hey Carl I will give your GP RS a run for you any time
Do you want a run on my 150 diesel LOL!!!
See you on Suday

SS90

18th April 2009, 03:48

I don't think that the MB is crankcase induction either, The reeds go into the back of the barrel.

Ok, thanks, for some reason I thought they where Crankcase induction, I am unsure why I thought that.... I never had one apart!

SS90

18th April 2009, 04:09

So the problem is more about increasing the torque than making more Hp.

How can we use the new style of porting to increase the torque? SS90 do you have any suggestions?

.

Ok, the first thing you want to spend your time on is more complete scavenging of the crankcase at BDC.

Believe me, this is going to increase your torque dramatically!

Put very simply, the easiest way to make torque in your engine is to pay attention to this part of the cycle.

We looked at your rear "transfer/boost port", and from the piston window placement, it's as high as you can really go.

I will draw an idea I have for improving that on Sunday night and post it.

With the shrouding of your transfer ports via the piston transfer cutaways, you really are losing alot of torque there.

However, as you pointed out, you cannot safely remove too much material from the piston in this area, as it causes failures......

I realise that another piston is not really an option (particularly at this stage), so look at a safe way of unshrouding this area, ( I mentioned small holes around that area as an example, is that possible? as I assure you that this will be a worthwhile effort....

I have seen as much as 15% torque gains from attention to this... (this example was not just a one off engine, it was on a series production cylinder)

Before talking about transfer angles, it would also be VERY prudent to look at the possibility of including a divider between the primary and secondary transfer ports, I realise this is no simple task, but again, the gains you will make are quite astounding.

If you cannot have a divider, then the application of some (though not all) modern porting techniques will be "for nowt", as this (divider) is an important part in the whole cylinder scavenge pattern

Sure, to have one going right up the cylinder is not really feasable, but if you could come up with a way of fitting a divider even just at the top, where they enter the cylinder, you will be well rewarded!

Is that something that can be achieved with this cylinder?

I mentioned a few weeks ago the idea of drilling into the outer liner, and fitting a divider at the port edge, (made from alloy) and then welding it in place....can this be achieved?

Don't get me wrong, if none of these things can be done, I can still help with a scavenge pattern, but if the things I mention can be done, the gains are dramatically better!

If you need some ideas for shaping the piston cutaways, I can post a picture or 2 of ideas that I use.

TZ350

18th April 2009, 07:41

Ok, the first thing you want to spend your time on is more complete scavenging of the crankcase at BDC.

Put very simply, the easiest way to make torque in your engine is to pay attention to this part of the cycle.

With the shrouding of your transfer ports via the piston transfer cutaways, you really are losing alot of torque there.

Thank you SS90 for reminding me of these ideas that you have mentioned before.

Crankcase scavenging and transfer port windows that is where I will get busy now.

I am looking forward to seeing your drawing for the rear boost port and would be interested in a pic of the pistons.

I have a bunch of questions but I need to make drawings and pic's to illustrate them.

.

TZ350

18th April 2009, 08:17

With the shrouding of your transfer ports via the piston transfer cutaways, you really are losing alot of torque there.

so look at a safe way of unshrouding this area, ( I mentioned small holes around that area as an example, is that possible? as I assure you that this will be a worthwhile effort....

Pic 1, is this the port divider you mention? I can do this.

Pic 2, I can cut the GP cylinder away to look like this and drill holes in the piston skirt.

Pic 3, I could open up the secondry transfer window and put a divider here and also extend it down into the crankcase if that would be a good idea.

.

SS90

18th April 2009, 18:41

Pic 1, is this the port divider you mention? I can do this.

Pic 2, I can cut the GP cylinder away to look like this and drill holes in the piston skirt.

Pic 3, I could open up the secondry transfer window and put a divider here and also extend it down into the crankcase if that would be a good idea.

.

Ok, yea, that's all pretty good!

I would just be a little careful of how much I cut the liner away, as you really need to support that piston, don't sacrifice too much safety on that area!

F5 Dave mentioned a while back about putting the cylinder in each case half (as you did of course), this is the best way to decide how to scavenge the cases.

I like the idea of extending the divider down onto the case, it's something I have done before, and seemed to be of benefit.

I remember you had access to an old Honda RS125 cylinder..... is there any way you could spend a few hours with that?:drool:

In my opinion, the RS125 cylinder has the best design of all in this area........

The two pictures I have attached relate to the piston transfer cutouts.

The first one ( an old Polini piston with the seizure marks) is what I seem to be able to get away with (as far as increasing the cutout), with out having piston failures, and it certainly works.

It's not semetrical because of the large transfer/boost window on the skirt, and as you know you need to leave more material in this area, particularly because there is very little internal webbing on these pistons......

The second picture is just for demonstration purpose, and is a high quality aluminium/silicone/copper piston, that uses the mould from a TZR250.

I put it in an original 125cc Vespa cylinder (very very low tech)as an example of how different each manufacturer designs their cutaways

depending on if you have Transfer boost ports (like most modern two strokes) is how much attention the Japanese paid to this area.

As such, the use of a modern piston (designed to be used in an engine with systems like transfer boosts etc) face the problem of masked transfers when used in older designed engines, that rely heavily on this area to clear the crankcase at BDC.

Even though you have a little "boost port" in your cylinder, it's quite small, and I am confident too say you will make gains here!

This is why Malossi adapted the extra port system (they call CVF, but really was developed in the 30's by Royal Enfield), and they use extra boost ports on the back wall as well.....basically, it seems you can never have enough ports working on this concept!

Also, "Trinity" RZ350 variant cylinders use this system (as well as transfer boosts)

But, I'm not saying you should do that!

It's just an example of how there are still companies using this "style" of tuning.

If you have transfer boosts, you don't really seem to pay attention (as much) to crankcase scavenging, as it is compensated for by just adding more fuel via the transfer boosts!

It's not good for fuel economy (or pollution), but an easy way to make power!

If you don't (can't) have this type of boost port, then it becomes more important to "work with what you have"

With this piston, you see how big the internal webbing is, which allows you to really "flow" (hate that word actually) this area and unmask it quite well, compared to other pistons, that this webbing is quite often too small to allow any material to be removed.

From the pictures you can get a rough idea of how much you can safely remove with-out compromising strength.

As you know, this webbing on a piston is where all the strength is.

What does this area on the piston you use look like?

Also, can you post a pic (or drawing) of your crankshaft....I'm just unfamilure with a GP125 crank!

SS90

18th April 2009, 23:38

O.k,

These are some pictures cylinder of one of my cylinders.

It is "almost" finished in these pictures. (port chamfering to be completed etc), and a couple of other things. And of course the transfer area of the liner is still to be matched to the piston.

At the stage I took these photo's I was still experimenting with piston transfer cutout shapes.

125cc Cast ironed lined. I only used a single ring piston on this one engine, as at that stage it was the only one I could get. I now have a two ring item that I was able to get here.

It was my first experiment with transfer boosts, and divider lengths/angles.

You will see that the divider does not go all the way to the base of the cylinder in this liner, but on this set up it is a hinderance (because of the transfer boost ports), the absence of which (like your cylinder) allows that you can go right to the base.

While it makes good power, I still prefer the non transfer boost cylinders for the spread of power.

You can see my port angles clearly

In regards to the piston cutouts...... Ermmmm.... let's just say this one was "a little too much":weep:

when I changed pistons to the one I use now (that have the extra webbing like my previous post) I was able to keep strength, and unshroud more.

Yow Ling

19th April 2009, 10:02

Is the "transfer Boost Port" the same as Boysen Port. A tunnel connecting the transfer port to the inlet ?

craisin

19th April 2009, 13:53

Is the "transfer Boost Port" the same as Boysen Port. A tunnel connecting the transfer port to the inlet ?
Its like comparing apples to pears

TZ350

19th April 2009, 18:58

Is the "transfer Boost Port" the same as Boysen Port. A tunnel connecting the transfer port to the inlet ?

SS90 I am also unsure what you mean by a "boost port".

Great pictures, very helpfull.

Yow Ling

19th April 2009, 19:08

Its like comparing apples to pears

So the new bag of Mexican Tripping weed arived i see.

TZ350

19th April 2009, 19:09

Mt Wellington points races. Wound on a bunch of pre-load and increased the rebound setting just like Sully60 sugested and it made a heap of difference. The bike kept a much tighter line and I was able to experiment with getting the power on earlier. Thanks Sully.

The problem now is, that I am arriving at the next corner faster than before and its taking some getting used too. On some accasions I was getting front wheel chatter coming around the sweeper at speed, I will need to look into that. A bit frightening but who cares, things are looking up.

The bike starts like a rocket and in one of the "A" grade points races I was first into the first corner and made a whole lap before being overtaken. Things are starting to look possible. Going to get out for some practice before the next meeting.

And Taupo should be fun.

.

TZ350

19th April 2009, 20:01

Can you post a pic (or drawing) of your crankshaft....I'm just unfamilure with a GP125 crank!.

GP125 crank with the inlet side champhered and the bigend pin hole bored out from 19mm to 22mm. This was done when I thought that I needed a better rod to withstand the extra reves. As things have worked out the standard rods/bigends have worked well in the other team ESE bikes. The plan is to stuff the ballance holes with devcon F putty.

Pic 1 and Pic 2, modified GP125 crank.

Pic 3 GP125 rod/bigend and on the right hand side RD350 rod/bigend.

.

TZ350

19th April 2009, 20:08

From the pictures you can get a rough idea of how much you can safely remove with-out compromising strength.

As you know, this webbing on a piston is where all the strength is.

What does this area on the piston you use look like?

Pic-1 the cast reinforcing web that gets cut away to unmask the transfer on my engine.

Pic-2 the Wiesco piston does not have this web and may be a better bet.

Pic-3 a Honda RS125 piston.

Pic-4 Kawasaki cast piston and Wiesco forged piston.

Pic-5 Kawasaki piston with cutouts like SS90 has been discribing.

.

craisin

19th April 2009, 20:27

So the new bag of Mexican Tripping weed arived i see.

no such luck I think Boysen ports use Boysen Reeds which seems to be 2 sets of reeds arranged in a vee .
And you need a bigger port to accomidate them.
2 strokes are not all the same as you have rotary disk engines that uses a hole in one of the crankcase webs instead of reeds and the air-fuel mixture is inducted into the crancase to the tranfer slots and a cut out in the side of the piston uncover hole thru to the cylinder.

there are heaps of links in this thread that explain the different workings of the different 2 strokes k

TZ350

19th April 2009, 20:44

I would just be a little careful of how much I cut the liner away, as you really need to support that piston, don't sacrifice too much safety on that area!

F5 Dave mentioned a while back about putting the cylinder in each case half (as you did of course), this is the best way to decide how to scavenge the cases.

I like the idea of extending the divider down onto the case, it's something I have done before, and seemed to be of benefit.

Pic-1 The cylinder in the case and the liner cutout does not match the transferport exactly.

Pic-2 Shows the size of the transferport window with the piston at BDC.

Pic-3 Shows the size of the transferport window with the long rod and 13mm cylinder packer, the window is much larger and the transfer divider looks like it could be brought down to here.

In pic-3 you can see how much of the pistion needs to be cut away to completly unmask the transfer window. There are limitations of course like leaving enough piston skirt to cover the exhaust port at TDC.

.

SS90

19th April 2009, 21:13

Pic-1 the cast reinforcing web that gets cut away to unmask the transfer on my engine.

Pic-2 the Wiesco piston does not have this web and may be a better bet.

Pic-3 a Honda RS125 piston.

Pic-4 Kawasaki cast piston and Wiesco forged piston.

Pic-5 Kawasaki piston with cutouts like SS90 has been discribing.

.

I believe that if you where to cut away too much of the piston you use, you would be "dating disaster", bit I think you mentioned when you took too much away previously you had cracking problems? This I would believe!

The wiesco piston looks more heavily engineered (which is why I suspect it has no webbing), and as such it's safe to assume you can remove more material than the other pistons, as the skirt thickness is much more substantial.

An advantage of the Wiesco piston (in my opinion) is because of the thick skirt walls, you are more likely to be able to have a closer to semetrical shape in the cutaway.

The RS125 Piston (although you cant use it) would be the best one. It has a nice big cutaway, and the webbing runs all around it radius.... nice and strong!

The Kawasaki piston also would be wort a second look.... I wonder if that piston has webbing running all through it's cutaway radius?

I don't know, (I suspect that it does though)

But, yea, the Wiesco looks quite "rugged" and could easily stand some removal of material!

SS90

19th April 2009, 21:21

SS90 I am also unsure what you mean by a "boost port".

Yea, sorry, it's easy to get confused when you use different terminology! Sorry!

Like Yowling suggested, when I refer to a "transfer boost port", I do mean the Eric Boysen designed reed petal controlled system, it's just that it has been out of copyright for so long now, that it is more often reffered to a "transfer boost", or I have recently heard it reffered to an "auxillery transfer port"

But, of course, there are other types boost ports, depending on what type of intake system you have (piston window induction, or crankcase induction etc) and I use this term (in the context of your engine) in reference to any extra port, or series of (controlled by the piston normally) that aid in scavenging of the crankcase at BDC.

SS90

19th April 2009, 21:30

no such luck I think Boysen ports use Boysen Reeds which seems to be 2 sets of reeds arranged in a vee .
And you need a bigger port to accomidate them.
2 strokes are not all the same as you have rotary disk engines that uses a hole in one of the crankcase webs instead of reeds and the air-fuel mixture is inducted into the crancase to the tranfer slots and a cut out in the side of the piston uncover hole thru to the cylinder.

there are heaps of links in this thread that explain the different workings of the different 2 strokes k

Yea, your right Crasin, I guess your comment about Apples and Pears is quite correct.

Teezee's engine is "Disc Valve", and as such, "boysen ports" (or transfer boosts, as I called them) are not relevent!

To compare the boost port systems of a piston window induction (like the ones I posted) to Teezee's Cylinder is indeed "Apples to Pears"

I included them because I wanted to demonstrate how previously manufacturers, if they used this "Boysen port", they did not have the need to worry so much about crankcase scavenging, as they compensated for this by simply "putting more fuel into the transfers"

And, as such the piston cutaways are quite alot smaller than they should really be, particularly in an engine like Teezee's GP125, where crankcase scavenging has become more important (due to some limitations of the design, etc)

In the picture I posted, I had tried to use both "styles" of tuning..... Like Trinity do with there RZ350 variant cylinders (although they use ports cut above the piston gudgeon pin, (like the Royal Enfield racers from the 30's, or Malossi tuning), and I simply cut away as much of the piston cutaway as I can, without weakening the piston too much!

TZ350

19th April 2009, 21:40

SS90 thanks for the explination.

SS90

19th April 2009, 21:46

.

GP125 crank with the inlet side champhered and the bigend pin hole bored out from 19mm to 22mm. This was done when I thought that I needed a better rod to withstand the extra reves. As things have worked out the standard rods/bigends have worked well in the other team ESE bikes. The plan is to stuff the ballance holes with devcon F putty.

Pic 1 and Pic 2, modified GP125 crank.

Pic 3 GP125 rod/bigend and on the right hand side RD350 rod/bigend.

.

OK, great! That's awesome!

There is quite alot you can do with this crank, but first you need to do some "donkey work" I am afraid!

I am sure you are aware why the cutouts are there in the crankweb..... are you able to take a picture of the position of these cutouts (with the crank in one case half, with the piston on the rod, at BDC)

see then what masking you have in regards to the crank web/piston cutout area......

Then, you need to fill your balancing holes as you suggested, and, with out further mods, accurately measure your primary compression..... when you know that, I can show you some methods of improving this area.... (It's all work that can be done at home, but requires removal of material from your webs, and as such will lower the primary compression.... and I like to see no less than 1.48:1

Skunk

19th April 2009, 22:01

I am sure you are aware why the cutouts are there in the crankweb...
I'm not. Can you explain please?

SS90

19th April 2009, 22:10

Pic-1 The cylinder in the case and the liner cutout does not match the transferport exactly.

Pic-2 Shows the size of the transferport window with the piston at BDC.

Pic-3 Shows the size of the transferport window with the long rod and 13mm cylinder packer, the window is much larger and the transfer divider looks like it could be brought down to here.

In pic-3 you can see how much of the pistion needs to be cut away to completly unmask the transfer window. There are limitations of course like leaving enough piston skirt to cover the exhaust port at TDC.

.

Yea, it really is quite bad........ by the amount of material you need to remove (not all of course), I am starting to think that the Kawasaki piston is a better option.... how much so you feel you can remove from the Wiseco piston?

I personally run into such problems when I "stroke" an engine, (be it one of mine, or another manufacturer (Poloini, Malossi, Falc, Quatrinni, whatever) and the only pistons I use in these situations have large webbing that allow alot of material to be removed!

Either that, or the manufacturer (particularly Falc allow for this in their pistons, and use a piston that is of high quality, and thick enough in the skirt wall section to not need webbing... I suspect much like the Wiesco one you showed!)

TZ350

19th April 2009, 22:10

I am sure you are aware why the cutouts are there in the crankweb..... are you able to take a picture of the position of these cutouts (with the crank in one case half, with the piston on the rod, at BDC)

I have allways thought the cutouts unmask the bigend thereby facillitating its lubrication. The cutouts would be at BDC when the piston is at BDC. Is there another purpose for these cutouts?

.

SS90

19th April 2009, 22:16

I'm not. Can you explain please?

Ok, well, it may be best to explain it like this.

The air and fuel, after it has entered the crankcase (via the timed disc), is pushed up to the cylinder via the transfer ports...... the fuel and air, goes between the crankwebs (not around the outside........) the cutaways are designed to improve this!

It primarily increases lubrication to the bearings......but you can use the same concept to improve transfer operation!

By that I mean, cutouts added to the inner edge of the webs when the piston is at BDC

SS90

19th April 2009, 22:19

I have allways thought the cutouts unmask the bigend thereby facillitating its lubrication. The cutouts would be at BDC when the piston is at BDC. Is there another purpose for these cutouts?

.

Yes, you are quite right, but, also using the same concept, with new cut outs in the web (when the piston is at BDC new cutouts that align with the cutouts in the piston ), particularly when you have masking problems (such as you do) this can really help (with out having to take so much off the piston)...It is a technique that is quite often used when you "stroke" a cylinder, not so much as a result of the longer stroke of the crank, but because doing so requires the spacing up of the cylinder (like you have done, but for different reasons ), and as you see, the piston now masks the transfer area, and you are unable to use the extra crankcase volume effectively!

It's not 100% effective, but every little bit helps (and it requires only a small amount of time)

F5 Dave

20th April 2009, 10:15

I don't think that the MB is crankcase induction either, The reeds go into the back of the barrel, I was under the impression a case inducted motor was when the reeds feed straight in the back of the crankcase, leaving the opportunity to play with quite significant boost port sizes and more space for transfers.

Sorry to take this off topic, what head volume do you think would be optimum for the H100 dave? I was going to set it up at about 14:1 as the gear box works well, so a narrow power band isn't a problem.

Nobody so far has referred to what fuel they are running when talking compression ratios. Type of power & pipe, particularly baffle are important, as is general head design. The H was pretty touchy on ignition timing as the baffle was real steep angle, I suspect your RS pipe will not be anywhere as bad. I'll look up my old notes & PM you. 14:1 in that 100cc engine on 98 should be fine. I was running Av, although that brings up throttle response issues in some engines, never seemed to be a problem.

TZ350

20th April 2009, 16:28

Nobody so far has referred to what fuel they are running when talking compression ratios. Type of power & pipe, particularly baffle are important, as is general head design. The H was pretty touchy on ignition timing as the baffle was real steep angle, I suspect your RS pipe will not be anywhere as bad. I'll look up my old notes & PM you. 14:1 in that 100cc engine on 98 should be fine. I was running Av, although that brings up throttle response issues in some engines, never seemed to be a problem.

Running 91, we are currently running Av gas but when we have worked through our current issue (crankcase scavinging) we are planing on using one bike to explore the possibilites of using 91. As we have the idea that a lower octane fuel is faster burning. Allowing us to retard the ignition and get less negative work on the piston BTDC. I remember you hinting at this before. Do you have any pointers to set us off in the right direction or are we staring down yet another blind alley.

.

k14

20th April 2009, 17:03

Running 91, we are currently running Av gas but when we have worked through our current issue (crankcase scavinging) we are planing on using one bike to explore the possibilites of using 91. As we have the idea that a lower octane fuel is faster burning. Allowing us to retard the ignition and get less negative work on the piston BTDC. I remember you hinting at this before. Do you have any pointers to set us off in the right direction or are we staring down yet another blind alley.

.
Stick with avgas. All the GP bikes love it, it makes the parts last longer and it very good at avoiding detonation. If you are helbent on using unleaded then I think the only option would be 98. This is just from experience from running my RS125.

F5 Dave

20th April 2009, 17:06

Um fuel is a difficult one, the best stuff I’ve used is the leaded super from the early 90s. I’ve read many articles, mainly MX based as to why Av Gas is a crap fuel in a high performance high revving 2 stroke.

From this point you will get as many opinions as if you were stupid enough to ask what the best oil to run is.[arrrgh]
[edit] (not aimed at Kirk above, I was mid type when he posted)

Of course you can’t just buy VP or whatever at the local shop as cheap as Americans or Europeans can. Specifically illegal for buckets anyway.

Best option is to trial & see what work in your application. Our 3 (4?) options are of course 91, 95/98 & Av

In my dirtbikes I run ½ av & ½ 91. The theory being that 91 has the least aromatics (which are also bad for throttle response) & mixing it with a reasonable dose of leaded fuel should bring the octane up to about 98 (it’s not just a averaging of the ratings) & hopefully cocktail the closest approximation to what we used to get. The preceding is just conjecture, with no real testing except that they run real nice & are consistent with jetting & give good response & power using reasonably high compression ratios which suits enduro & trials bikes.

Straight 91 you may run into detonation issues pretty quickly. Lead is a great octane booster (& the only one legal in F4/F5 before the backyard chemists start up). You don’t need much Av to do quite a bit.

The class rules (& plain expense) means we have to make the best with some pretty average options. Trial what works best with your combustion solution.

[edit] high octane does not = highest calorific value, think about this.

k14

20th April 2009, 17:51

Um fuel is a difficult one, the best stuff I’ve used is the leaded super from the early 90s. I’ve read many articles, mainly MX based as to why Av Gas is a crap fuel in a high performance high revving 2 stroke.

From this point you will get as many opinions as if you were stupid enough to ask what the best oil to run is.[arrrgh]
[edit] (not aimed at Kirk above, I was mid type when he posted)

Yeah I have thought about going to unleaded (elf) and/or some high octane leaded (vp etc) but no one else in NZ does so why should I. The biggest incentive to keep using leaded for me is the lubrication help it has on service life. Apparently you can get around double piston and crank life using it (and with a piston costing nearly as much as a crank at $400 it adds up quickly). However I have modified the ignition timing, head volume etc to sufficiently account for the different characteristics of the fuel as the standard cdi is setup for unleaded. If it ain't broke, don't fix it I say.

As I said though, all my experience is from 125GP bikes and you are dealing with a completly different kettle of fish. Sorry for the slight hijack. :innocent:

F5 Dave

20th April 2009, 18:10

k14

20th April 2009, 18:12

Of course you used to be able to get leaded high performance petrol, probably still can. People have used it in RS125s in the past, but adds another layer of expense. The change over to unleaded as you say esp on RSs means a heap of different parts, ign curves to take advantage. A proper 125GP bike will rev a lot higher than a GP125 (sheesh that gets confusing) though.
Yeah I think when I looked into the VP good stuff (maybe 120 octane or so?) it was roughly $8 a litre. Then I have heard the elf is around twice that. Gets pretty expensive when you are going through 30L a weekend. I will stick to the tried and true $1.67 a litre avgas from the airport!!!

TZ350

20th April 2009, 20:56

As I said though, all my experience is from 125GP bikes and you are dealing with a completly different kettle of fish. Sorry for the slight hijack. :innocent:

Its all good. Interesting that the lead helps engine life.

A possibility for team ESE would be to make up two premixes 91 and Av Gas, then mix a small batch 50/50 like F5 Dave, do a dyno run. Dilute the 50/50 mix with some more 91 premix to say 60/40. Do another dyno run, dilute again Etc and see what happens.

From what Iv'e read recently. It takes about 50-60 degrees for the fuel charge to burn. Higher octane slower burn. Given the correct compression ratio and octane rating, ignition timing is adjusted so peak pressure occurs about 15 degrees ATDC.

A faster burn, needs less advance to peak at 15 degrees ATDC and creates less negative pressure (orange bit in pic) on the piston before TDC resulting in better BMEP or torque.

From what I understand, the calorific value or heat released per quantity of fuel burnt or power of the fuel does not matter, low calorific value, like methonal you just burn more of it.

What maters is how much oxygen (air) you can get into and keep in the motor.

More oxygen burns more fuel and that makes more power.

If the fuel burns faster and the fire can be lit later this means less negative pressure on the piston BTDC giving even more power at the back wheel.

The trade offs are compression ratio, octane rating, burn rate.

Whether we can get more power using faster burning 91 in the mix, who knows, when we can we will look into it.

F5 thanks for the tip about poor throtle response with Av Gas, I am having trouble with throtle response too.

.

SS90

21st April 2009, 05:02

From what Iv'e read recently. It takes about 50-60 degrees for the fuel charge to burn. Higher octane slower burn. Given the correct compression ratio and octane rating, ignition timing is adjusted so peak pressure occurs about 15 degrees ATDC.

A faster burn, needs less advance to peak at 15 degrees ATDC and creates less negative pressure (orange bit in pic) on the piston before TDC resulting in better BMEP or torque.

From what I understand, the calorific value or heat released per quantity of fuel burnt or power of the fuel does not matter, low calorific value, like methonal you just burn more of it.

What maters is how much oxygen (air) you can get into and keep in the motor.

More oxygen burns more fuel and that makes more power.

If the fuel burns faster and the fire can be lit later this means less negative pressure on the piston BTDC giving even more power at the back wheel.

The trade offs are compression ratio, octane rating, burn rate.

.

This all touches on a very interesting part of two stroke tuning... I used to think that attention to such details was not so important for low BMP stuff (for the likes of 125 GP bikes and upwards), but I have since learned otherwise.

In simple terms-

advancing produces a stronger mid range, and increases the "grunt" ( more Torque actually!) at the beginning of the power band, by allowing more time for peak-pressure to do work on the piston before the exhaust port opens. But this is over taken by the turbulance (correctly called "maximum-squish-velocity") at high RPM ( lets say above 7500 RPM ), and too much advance, as we all know causes detonation (or worse), but what so many people don't realise is that the reason too advanced timing causes such heat (and therefore heat related damage) is simply because you a firing too much before "peak pressure" and simply overheating the combustion chamber (and piston crown), as it is "fighting" itself, as it (the burning fuel) is trying to "push" the piston down, while inertia is trying to push the piston up!

retarding the timing at high RPM, causes heat to transfer from the cylinder to the pipe, keeping the cylinder cooler, and making sure peak-pressure occurs long enough AFTER TDC to prevent detonation. The extra heat in the pipe causes the tuned frequency to move upward - WIDENING (HINT HINT!) the power-band at the top end, and allowing the engine to over-rev more easily.

However, if you have your timing too retarded at this point, (too many degrees AFTER TDC) let's say the exhaust port is "half open" when it "burns", and this causes a huge flame front to "rush" out the now open port (that would usually/ideally be closed at this particular moment) this in turn causes more localised heating of the crown on the exhaust side, and so many people believe that this type of damage is only caused by compression ratios, or jetting, or TOO ADVANCED timing.... when quite often it is because of too much dynamic retard (firing too much after "peak pressure"

As you are aware, you are also fighting the resonance of the pipe, and as ignition timing effects your exhaust temperature, which if too retarded (hotter exhaust temp), will cause power loss below the resonance.

Unless you are lucky enough to have a full "programmable ignition" (that you can adjust every aspect of the curve) really (in my experience) the only gains you will realistically make with having a basic retarding ignition (such as what you use) on such low BMP engines is more "over-rev" at the end of your power curve, (and lower cylinder temp in the higher RPM as well, that is unless you retard it TOO much, which will cause increased localised heating of the exhaust side of the piston crown) however, if you do have the fully programmable item, AND an exhaust temp sensor AND a dyno then you can set the ignition (by changing curves) to really make serious gains, even on low BMP stuff.

I have personally seen 10% gains on more that one machine, just with the manipulation of the ignition curves, and I can tell you that is a big gain, just from ignition settings alone!

F5 Dave

21st April 2009, 10:29

. . .
From what I understand, the calorific value or heat released per quantity of fuel burnt or power of the fuel does not matter, low calorific value, like methonal you just burn more of it.
.
Yeah but like methanol or CNG whilst the Octane is super high the calorific value is low, (You pour in as much to match the air in, as you state for good combustion. That there is less energy is the problem.) but you can crank the compression up high enough to take advantage of the other side of the compromise.

When I changed from leaded super to Av gas I lost 1/2 hp (would hardly run on the 95 that we first got during the unleaded change over) on my 50. Despite any number of jetting ignition changes & about 6 different cuts of head with MSV, shape & comm alterations I never got it back. Old leaded pump gas was better fuel. Simple as that.

TZ350

21st April 2009, 13:10

Yes...... sometimes things just work better.

.

Brian d marge

21st April 2009, 13:18

What maters is how much oxygen (air) you can get into and keep in the motor.

More oxygen burns more fuel and that makes more power.

If the fuel burns faster and the fire can be lit later this means less negative pressure on the piston BTDC giving even more power at the back wheel.

.

Fuel doesn't burn faster , the reason you want a LOT of oxygen in there is to sniff out that naughty fuel molecule hiding round the back of the cylinder ,,, and get a complete(er) burn

Thats why Ducati back in the day started winning WSBK , they swapped over to fuel injection and started running HUGE big inlets ...what are they now 60mm?

With my Enfield I have retarded the valve timing to give better cylinder entrapment at low RPM , as I also run on a tight track and most of my throotle work is off the bottom ( no point tuning for top end when its all off the bottom !")

Also Ignition , you will be surprised how often the spark DOESN'T fire , off the top of my head around 17% that s a lot of wasted power right there !

Stephen

Buckets4Me

21st April 2009, 15:41

:dodge: :pinch:

TZ350

21st April 2009, 16:36

I also run on a tight track and most of my throtle work is off the bottom ( no point tuning for top end when its all off the bottom !")

Also Ignition , you will be surprised how often the spark DOESN'T fire , off the top of my head around 17% that s a lot of wasted power right there !

Stephen

no point tuning for top end when its all off the bottom!

you will be surprised how often the spark DOESN'T fire.

Two very good points to think about, thanks.

.

TZ350

21st April 2009, 20:33

.

After retarding the ignition and leaning it out and racing Kaitoke and Mt Wellington I lifted the head tonight for a look.

Pic-1 the dark ring on the head is where the inner edge of the barrel is and the copper inside that is the squish band. It all looks good.

Pic-2 is the piston, looks much better than it did after Taupo. In fact it looks pretty good.

Pic-3 checking the ignition timing with a degree wheel. Ignition was 17 degrees BTDC. I will file the stator plate slots to give myself more adjustment.

F5 we made a brass thingy for holding the degree wheel like you suggested.

Specs are:- Ex opens 81 ATDC 71% bore width, Trans open 114 ATDC, Inlet opens 142 BTDC closes 87 ATDC, Ignition 17 BTDC and compresion ratio 7:1 corrected and 13:1 uncorrected. Av-Gas 20:1 premix. RM125-spec pipe from G Bell's book.

The bikes making more power and is less thermaly stressed after its tuning session on Johns dyno.

.

SS90

22nd April 2009, 08:34

TZ350

22nd April 2009, 16:20

Hi Teezee,
In picture number 2, I am making the assumption that the exhaust side is on the right..... if that is the case, the oddball transfer/boost port arrangement of the GP125 works quite well!

Interesting about 17 deg for the ignition timing..... I was quietly estimating something between 17 and 20 deg static for your engine!

No. Exhaust is on the left, I should have said that when I posted the pic.

I will modify the backing plate so I can get more adjustment.

I would also like to try an ignition modual that has some built in retard, say about 10 degrees coming in near peak power. I have a RM125 black box to try.

.

TZ350

22nd April 2009, 16:21

If anyone wanted to know:………..

Engine power was greatest with the compromise bore/stroke ratio of 1.0 or 1.2
Combustion efficiency tended to decrease with increasing bore/stroke ratio.
Mechanical efficiency tended to increase with increasing bore/stroke ratio.
The specific fuel consumption tended to rise with increasing bore/stroke ratio.
The experimental investigation concluded that a square or slightly over square bore/stroke ratio produces an engine with the best brake performance.

From SAE Paper:- http://www.sae.org/technical/papers/1999-01-3342

.

SS90

22nd April 2009, 19:16

No. Exhaust is on the left, I should have said that when I posted the pic.

I will modify the backing plate so I can get more adjustment.

I would also like to try an ignition modual that has some built in retard, say about 10 degrees coming in near peak power. I have a RM125 black box to try.

.

Oh, I was a little hopeful on that!

In that case, you are not seeing a "scavenge pattern" on the piston for one of two reasons....either the rear boost/transfer set up is "short circuiting", (small pattern on the rear at the area of the boost/transfer ports) or the exhaust port is too wide, and heating that area of the crown too much (white colouring).

72% ( what you have from memory) is not enough to do this in my experience!

The pattern is "forming" though, and you can see the primary and secondaries showing a pattern (see pic)

As I wrote yesterday, having an ignition with too much retard will make you r piston crown exhaust side look like this (as well as too big exhaust port)

For some reason I thought you had a retarding ignition!

The correct setting (retard point (RPM) and amount of advance (degrees back) should help in this problem, but it may take a few different coils (that is where the "curve" is stored) as the wrong curve will make it worse!

I have found that almost all japanese twist and go scooter ignitions have between 7 and 11 degrees set in them.....is it easy/cheap to get a second hand one in NZ?

TZ350

22nd April 2009, 20:46

72% your probably right, I was working from memory for the width, I should have checked.

When I looked at it in the flesh, the piston was a uniform colour all over with a grey colouring on top that looks like it was just misted over lightly with a spray gun after the piston was painted brown.

The ports are not square across the engine but are turned like a T500 Suzuki's. The rear boost/transfer port would be at the 2oclock position and the exhaust port at 7 oclock in the pic.

The dark area in the dish at 2 oclock, is that the boost/transfer port blowing straight across the piston towards the exhaust? And the lighter areas either side the mains and secondrys blowing towards the back.

I have been working on a retarding ignition, it appears in earlier posts. I intend getting back to it.

My CDI unit consists of three main pieces, stator coil, black box and high tension coil. When you say the "Curve" is stored in the coil, which coil do you mean?

I will look into the possibility of a scooter ignition, thanks for the tip. I have several RM black boxes and plan to make a wiring adaptor and try them. I will get something sorted very soon as we plan another trip to the dyno at Henderson Yamaha and I might get to run my bike this time.

My bike is still "as is" from the first dyno session at Johns and it would be good to get a graph to compair to the others done at Henderson Yamaha the other day. If I can I will have a retarding ignition to try too if I can make something that simply plugs in/out.

Dynos are becoming addictive.

.

Brian d marge

23rd April 2009, 01:55

I have found that almost all japanese twist and go scooter ignitions have between 7 and 11 degrees set in them.....is it easy/cheap to get a second hand one in NZ?

u can buy performance ones cheaply to , but its that blasted potting in them , if anyone can figure a way to get that stuff out with out hurting the electronics ,,,Im all ears

Stephen

PDL kits for my Enfield 300 pounds Sterling , Honda CR250 free ,,,I have a few lying about , black box ... and all it does is open when the correct cvoltage is reached , Well thats another story , If I could get one with a 10 deg Static advance , cool ! but the map might be different ! ..hey ho

Stephen

SS90

23rd April 2009, 05:59

When I looked at it in the flesh, the piston was a uniform colour all over with a grey colouring on top that looks like it was just misted over lightly with a spray gun after the piston was painted brown.

The ports are not square across the engine but are turned like a T500 Suzuki's. The rear boost/transfer port would be at the 2oclock position and the exhaust port at 7 oclock in the pic.

The dark area in the dish at 2 oclock, is that the boost/transfer port blowing straight across the piston towards the exhaust? And the lighter areas either side the mains and secondrys blowing towards the back.

My CDI unit consists of three main pieces, stator coil, black box and high tension coil. When you say the "Curve" is stored in the coil, which coil do you mean?

I will look into the possibility of a scooter ignition, thanks for the tip. I have several RM black boxes and plan to make a wiring adaptor and try them. I will get something sorted very soon as we plan another trip to the dyno at Henderson Yamaha and I might get to run my bike this time.

Dynos are becoming addictive.

.

Yea,sorry, when I refer to the "curve" stored in the box, it was a little vague!

What I meant was the fact that the CDI and the coil are the same unit on modern "twist and go's"!

Making it easy to simply swap to different boxes (coils/CDI units) in order to get different retard points (RPM), and different amounts of retard (degrees)

I first thought they would all be pretty much the same, but I learned otherwise!

Yea, with the crown of your piston, it is a little early to tell too much in regards to patterns just yet, as it does seem that your exhaust area is a little hot, and I would be presuming too much...

.....however, from what I see (and reading/seeing that you have a flat top piston), I would start to suspect that you would get some advantages by returning to a domed piston (if you where to leave the rear boost/transfers alone, and not change their angle)

I'm not suggesting you have to change your piston, as there are other solutions!

However, I am starting to go back to my original idea (a few weeks ago), that you should utilise the flat top piston, and try and combine the rear boost port and the two secondaries into one stream, and get a very high angle (right up into the combustion chamber), and try and use that dish in the piston to your advantage!

Remember that the scavenge pattern the Suzuki boys designed for this cylinder utilised a domed piston, and with a flat top, it's no longer working as designed!

If you had to run the cylinder and piston as it was, you could compensate for this changed pattern (caused by the flat top piston) by designing a chamber was better at "pushing" the wasted fuel back into the cylinder, but I think changing the rear port angles is better.... currently I do not feel you are getting the benefits that having secondary transfers normally provides!

But this is assuming too much, and I believe you need to lower the temp of the exhaust side of the crown to better see what is happening with your transfers!

TZ350

23rd April 2009, 16:57

Honda RS125 Ports as best as I can measure them:-

(F4) (F5) Etc refers to points in the Yamaha SAE paper and can also be seen in Pic-1.

Download the SAE paper from Yamaha on Port Shapes and Power:- http://www.2stroke-tuning.nl/media/pdfjes/porting.pdf

Bore 54mm Stroke 54mm R1=27 (F5) R2=12.5 (F4). The Piston has a very slight dome.

Transfer Port Opens 41.75mm-116 ATDC Inclined Up (F3) 30Deg P1=70 P2=30.

Auxilary Type-1 (F9) Port Opens 43mm-119.5 ATDC Inclined up 15 Deg.

Boost Port Opens 43.5mm-121 ATDC Inclined up 55 Deg.

Pic-1 The Data, Pic-2 The Honda RS125 Ports, Pic-3 The tools for measuring the port angles, Pic-4 The very clean edges in the ports, Pic-5 The piston at BDC, Pic-6 The crankcase port windows.

.

SS90

25th April 2009, 04:48

[QUOTE=TZ350;2041289]Honda RS125 Ports as best as I can measure them:-

(F4) (F5) Etc refers to points in the Yamaha SAE paper and can also be seen in Pic-1.

Download the SAE paper from Yamaha on Port Shapes and Power:- http://www.2stroke-tuning.nl/media/pdfjes/porting.pdf

Bore 54mm Stroke 54mm R1=27 (F5) R2=12.5 (F4). The Piston has a very slight dome.

Transfer Port Opens 41.75mm-116 ATDC Inclined Up (F3) 30Deg P1=70 P2=30.

Auxilary Type-1 (F9) Port Opens 43mm-119.5 ATDC Inclined up 15 Deg.

Boost Port Opens 43.5mm-121 ATDC Inclined up 55 Deg.

Pic-1 The Data, Pic-2 The Honda RS125 Ports, Pic-3 The tools for measuring the port angles, Pic-4 The very clean edges in the ports, Pic-5 The piston at BDC, Pic-6 The crankcase port windows.

.[/QUOTE=

Aweseome reading on the SAE papers Teezee!

Interesting on the port times (boost port and auxilleries opening at different times aye!)

The angles of the ports etc are pretty much (roundabout) where you should be heading..... I am just still a little unsure of flat piston at the moment.

As you know Rs125's are "square" engines, but I can't really remember ever seeing a modern port layout that differed if the engine was square or not.

(that said, I can't think of an "unsquare" modern performance two stroke engine off the stop of my head!)

From your recent reading, what does it lead you to conclude on the angles of your ports for your GP125?

TZ350

25th April 2009, 06:11

[QUOTE=TZ350;2041289] From your recent reading, what does it lead you to conclude on the angles of your ports for your GP125?

The transfer port and auxiliary port (upswept) angles are arse about face on the GP compared to modern thinking.

Also looking at the angles and kickers in the ports you can see how Honda and modern thinking have reduced exhaust short circuiting

I have been talking with Tomas, he will be back from Vietnam next week. He seemed to already be familiar with the modern thinking and has some experience with changing the transfer port roof angles. I will take pic's and post when he re works the cylinder.

I know we should just change one aspect at a time and dyno each step but I don't have the patience. We will give the spare GP cylinder a radical make over using all the ideas covered recently.

We are going to model our work on the RS cylinder but use the original RM-spec pipe to start with.

SS90 getting us looking in this direction has been very helpfull, it will be interesting to see what gains in driveability can be made.

I am making a modified first gear (in buckets the starts are everything) when I get that done I will strip the motor to fit it and do some mods in the case and pack the flywheel which should bring up the primary compression.

The new first driven gear will be generated with one less tooth but the same pitch circle. Makes for funny looking teeth and will probably be noisy but who cares, this is buckets. I will draw it up and have the blank water cut. Then I will turn the inside and form the driving dog slots before having it hardend.

.

TZ350

25th April 2009, 06:26

K14 and Sully60 have both encouraged me to pay more attention to improving my riding, and they are right. There are big big gains to be made there.

Following Sullys suggestions of more pre-load on the rear shocks I found I could start getting the power on earlier. The few times I got this right the bike fair flew around the corner, but it did show up a few more handling issues and my inexperiance with the extra speed. I was arriving at the next corner before I was ready.

Whenever I got the power on early, F...ck the bike flew and caught people up quick. I want more of this and when I have got used to the extra speed, there are going to be some very sorry 4-strokes at Mt Welly. :whistle:

Team ESE are planning to get down to Saturday practice's, we are all starting to get excited about our individual improvements.

I "borrowed" these pics from Tides post http://www.kiwibiker.co.nz/forums/showthread.php?t=97882 :blah: Pictures from Mt Wellington 19/4.

Unfortunatly I am not in the pic. I had got a good start and am out of the frame. I led the field for almost a lap before the fast boys started passing and I slowly drifted back through the field.

I was that annoying person we have all met while driving on the open road. You know the one, they go slow in the corners and speed up down the straights and its hard to get past. Well I am getting faster in the corners, much faster.

I can now see the way forward riding wise, and we are building a more drivable bike.

The next meeting should be good fun, especialy if it's wet.
.

TZ350

26th April 2009, 17:56

I was looking at fairings and it's occurred to me that the front of the lower fairing on a sport bike seems to share similarities to the design of the shroud in the link to aero engine cooling. Is this coincedence or by design.

I have been looking at this too, it must be design. On mine its a bit crude but I am trying to do something with the front number board and a duct attached under the top tripple clamp to direct air over the cylinder. I hope to fit a front guard from a RS125 to complete the effect. If you look hard at my bike number 14 in the pic above you might be able to make out where the duct is. It has the edges bent down, in the pic you can see one of the edges under the brake line.

.

Sketchy_Racer

26th April 2009, 18:29

Hey guys slightly off topic, but what do you think of this, I got my bucket on the dyno after some tweaking

H100
RS125 chamber (that doesn't work)
mild porting

TZ350

26th April 2009, 22:28

Inspired by TZ350 I have been looking over SAE papers,

...............and Whats This!!!!

"The drop in delivery ratio caused by increasing the crankcase volume can be fairly well compensated for by tuning the exhaust and inlet systems. "

from SAE Paper:- http://www.sae.org/technical/papers/670030

didn't Speedpro say this earlier? :blink:
.

I have just been reading that paper. What you say is true but it also shows that the ratio of 1.5 becomes more important as the rev's go up.

.

TZ350

26th April 2009, 22:32

Hey guys slightly off topic, but what do you think of this, I got my bucket on the dyno after some tweaking

H100
RS125 chamber (that doesn't work)
mild porting

That looks pretty promising, better than our GP's.

.

Sketchy_Racer

26th April 2009, 23:06

Thanks TZ, I have to say I have learnt a great deal from your thread and have throughly enjoyed the posts from yourself and SS90.

With my bike the majority of the work had already been completed by F5 dave, but looking at his old dyno sheets it looks like i've managed to extract a great deal more mid range which i was after and about 1hp on the top end.

I think once I have built a chamber to suit the motor exactly, 20HP will be very achievable, while keeping the nice power curve. I am yet to try different ignition timing as well, im sure more could be picked up with that too.

I would say that given this motor is a 100cc aircooled, that you 24mm carb on your 125 is the definite limiting factor on your motor. I have a 28mm, and am looking at going slighly larger yet.

SS90

27th April 2009, 09:34

Hey guys slightly off topic, but what do you think of this, I got my bucket on the dyno after some tweaking

H100
RS125 chamber (that doesn't work)
mild porting

It makes peak power for a very long time, I am of the opinion that it's a credit to the tuner(s)

It would be interesting to see it with a more suitable pipe...... do you know how many RPM an "established" fast MB100 engine revs to?

I just ask that because 11,000 is VERY high speed (in my opinion) Do you intend to have the engine rev to this RPM, or are you designing a pipe for lower RPM?

As we have discussed recently, 10 FTLB (13NM) of torque is quite a bit lower than can be achieved with a 100cc engine...perhaps your new pipe design can improve on this?

what changes have you already made to the RS125 pipe?

F5 Dave

27th April 2009, 09:36

Good result Sketchy, that is a heap stronger across the board. The pipe I had on it originally was a cock up but it was a fun bike, the 50 the serious one. It was my first pipe design with TSR sw & I was heading for supercross power as that seemed like a good idea for kart tracks. It was quite effective on those tracks, even if the power looked odd it fair launched out of corners, but more importantly it was an absolute hoot to ride. Thanks for not posting the old curves, I'm not hugely proud of them.

I later ran the bike with another pipe & barrel setup that I borrowed. It confirmed my original fear that any more power in that old frame made it pretty scary. Hence I needed to start again.

My RGV150 sleeved 125 made a similar powercurve using RS125 pipe. But was even flatter still, made ~19 & over 16hp for 4000rpm. Strangely it felt peaky on Slipway & I was faster on my 50. Odd huh?

PS the MB/H engine will last several seasons at those revs. (as long as crank built properly) But throw some new rings in every so often hey?

Sketchy_Racer

27th April 2009, 17:52

It makes peak power for a very long time, I am of the opinion that it's a credit to the tuner(s)

It would be interesting to see it with a more suitable pipe...... do you know how many RPM an "established" fast MB100 engine revs to?

I just ask that because 11,000 is VERY high speed (in my opinion) Do you intend to have the engine rev to this RPM, or are you designing a pipe for lower RPM?

As we have discussed recently, 10 FTLB (13NM) of torque is quite a bit lower than can be achieved with a 100cc engine...perhaps your new pipe design can improve on this?

what changes have you already made to the RS125 pipe?

I will aim to get the peak at about 10500 - 11000 RPM. As I understand it, the dip followed by the peak in the graph is caused by the chamber not working untill well after the porting has finished working at its desired RPM and as the RS Chamber I have has no modification at all so far, I think it's volume is far greater than what optimum would be but that as much as I know so far. When I look more into the chamber, I have a better understanding as to what was wrong with the RS Chamber and what I need to build. I am looking forward to building the chamber.

I definitely believe that greater than 10 FTLBs torque is achievable with the chamber alone, also we ran out of Jet sizes so I didn't get to find out if we were at the optimum jet size for power either.

Good result Sketchy, that is a heap stronger across the board. The pipe I had on it originally was a cock up but it was a fun bike, the 50 the serious one. It was my first pipe design with TSR sw & I was heading for supercross power as that seemed like a good idea for kart tracks. It was quite effective on those tracks, even if the power looked odd it fair launched out of corners, but more importantly it was an absolute hoot to ride. Thanks for not posting the old curves, I'm not hugely proud of them.

I later ran the bike with another pipe & barrel setup that I borrowed. It confirmed my original fear that any more power in that old frame made it pretty scary. Hence I needed to start again.

My RGV150 sleeved 125 made a similar powercurve using RS125 pipe. But was even flatter still, made ~19 & over 16hp for 4000rpm. Strangely it felt peaky on Slipway & I was faster on my 50. Odd huh?

PS the MB/H engine will last several seasons at those revs. (as long as crank built properly) But throw some new rings in every so often hey?

Thanks Dave,

I have changed very little from when you had the motor, most of it was case matching and just cleaning all the ports. The only thing I did modify largely was the head, It has a completely different profile and volume now.

And I knew that after riding the H100 Chassis once it was a dog and I needed to replace it. Although my RGV chassis still has quite a bit of work before it handles like it should. All in good time.

I didn't build the new crank but I checked all the tolerances and set it up in the cases all per the Graham Bell book. I did how ever put the balance shaft back in, as in the ally frame the vibration was phenomenal! After riding yesterday I am glad I did put it back in, much much smoother.

Do you think that your gearing may have been influencing the peaky feel on your RGV125 at slipway? In the wet (yesterday) my bike felt quite peaky, but I think that is due to me dropping out of the meat of the power and in the wet made it feel like it came on hard, but I think in the dry it will feel almost flat.

And yes I will be keeping this one up to scratch, It's only running one ring and I have the other one here to put in for a freshen up probably after this season if it doesn't shit itself (touch wood)

Cheers,

-Glen

F5 Dave

27th April 2009, 18:37

It is odd that my 125 felt peaky at Slipway, but really flew at Taupo & felt flat, like it was (if you remember I trailed you on your RS for a while in practice, . . . until you worked out where the handbrake was, - I don't care if you had an excuse, I'm taking it as a moral victory:second:). I had super low gearing so no that wasn't an issue at Slipway.

At those (low) revs I wouldn't be sure if 2 rings would be any disadvantage. As usual the best way would be to test it, but I doubt there is much in it. I only run one on the 50, but it spins pretty fast.

speedpro

27th April 2009, 20:51

A built MB100 with genuine honda bits is good for 14,000rpm and the crank will last 6 years of lots of racing monthly. If you use standard MB pistons every now and again you will lose the tip off a ring. Our sidecar had over 14rwhp between 9,000rpm and 13,500rpm and made a solid 19.9rwhp for approx 1000rpm.

Old #6 made 22.5hp at less than 11,000rpm and pulled cleanly from 4,000rpm or so.

The new, yet-to-be-built-Wobbly-spec engine is designed for 14,000rpm and hopefully will make serious power.

SS90

28th April 2009, 08:23

A built MB100 with genuine honda bits is good for 14,000rpm and the crank will last 6 years of lots of racing monthly.
Old #6 made 22.5hp at less than 11,000rpm and pulled cleanly from 4,000rpm or so.

The new, yet-to-be-built-Wobbly-spec engine is designed for 14,000rpm and hopefully will make serious power.

That sounds awesome Speedpro! While I hate to deviate from the subject of this thread (further than it already has......), do you have some dyno graphs for that engine? I would love too see them!

Pulling cleanly from 4000 RPM (and making full power at just over 10,000 RPM...and revving to 14,000 RPM..... that could suggest a 4000 RPM wide spread of peak power......) for a 100cc air cooled two stroke is very respectable (to say the least!)

My experience suggests that you would be making over 23 NM of torque (at a little over 10,000 RPM) to be doing that......

I'm not knocking you, I just really like to see what others are doing, because that really is a good engine!
:scooter::scooter::scooter::scooter::scooter:

speedpro

28th April 2009, 19:55

I'm not knocking you, I just really like to see what others are doing, because that really is a good engine!
:scooter::scooter::scooter::scooter::scooter:

It was a good engine until I downshifted without the clutch at max revs - see avatar! Put me in hospital for days.

I do have the dyno charts but they have faded pretty bad. I've tried scanning them but the results aren't good. The high revving sidecar engine only made 19.9rwhp but the other one made 22.5rwhp and didn't rev over 11,000rpm. Both were a joy to use with their broad spreads of power. My old TS100 made 19.9rwhp as well and had a huge power spread which was all wrong for a motor with 200deg of intake and exhaust timing.

craisin

28th April 2009, 21:12

hey speedpro I often wondered what your avatar was ,
I blew the image up .
Looks like the conrod would make a good work of art

speedpro

29th April 2009, 22:03

speedpro

29th April 2009, 22:12

Thread hijack . . . .

I scanned this as well just for giggles, this motor had 4 bent exhaust valves - daylight visible through one when the runs were done. It was WAYYYYY peppier with new o'size valves.

TZ350

29th April 2009, 22:22

Its very interesting to see these dyno graphs. Speedpro the last graph, is that your turbo charged Kawasaki Post Classic racer?

.

TZ350

29th April 2009, 22:27

Finally got a scan showing the TS100 and the MB100 sidecar. Ignore the red graph, that was a failed experiment. The TS went to 12,000, the MB went to 13,500. I actually don't have a chart of old #6 MB100.

The TS looks like 14hp @ 6K, peaks at 20 and falls back to 14hp at 12k. Very impressive.

.

SS90

30th April 2009, 10:02

I hope no one feels that I am turning this into a pissing contest, but for the sakes of comparisons,

This is an old engine from last year...133cc's cast iron (polini), quite alot of work.... (same specs as the one I showed some pics of last week or so) with the prototype of one of our new ignitions (the red line), compared to a standard electronic ignition (original electronic ignitions have 2deg Advance opposed to 11 Deg retard)

The Carb is also 28mm (so it's not quite as comparable as I would like, but all in good time)

It is possible to get more peak power (and certainly much more RPM), but doing so sacrifices too much torque (particularly at low RPM), and,like Teezee's GP125, these engines all have 4 gears.....as such, in my opinion (and experience) this would be quite close to what sort of curve you would like to see on your engine Teezee (although your exhaust timing is quite alot higher than this one, so possibly you won't quite achieve this spread of power!, but will certainly rev higher!)

TZ350

30th April 2009, 10:43

Is this the new generation porting and pipe?

F5 Dave

30th April 2009, 10:47

SS90

30th April 2009, 11:16

Is this the new generation porting and pipe?

Yes, while the porting is not "cutting edge", it certainly is in the latest direction.

The pipe is the exact same one as I have on my ss90 now (but of course the cylinder I use is one of my own)

The pipe design is quite old (about 3 years) and what we use for my cylinders now is quite "cutting edge" (well, in my opinion anyway), and the engines rev to 10,000 RPM, and make peak power for about 3,000 RPM

There is nothing revolutionary about the exhausts I use, it's just "up to date" and learned from what other people have done (as well as myself)

SS90

30th April 2009, 11:36

That is quite a lot of power from such low revs. But with 4 gears I suppose it is geared fairly high. There is only a 2000rpm spread, doesn't it fall out of power in taller gears? Or are they close enough in an all gears run?

Yea, as I am sure you aware F5dave, that is what is particularly hard about tuning a twostroke....making power in low revs.

I experimented (and still do) alot with port timings, exhaust temps, transfer timings ignitions etc etc etc when I first started this job, as it was fairly easy to make more power than most other people, but getting these engines to "pull fourth gear" was really difficult (when you had exhaust timings closer to what Teezee is using.

With the early "peaky" engines I used to make, I had to run a primary ration of 2.86, which even then was ONLY JUST low enough!

There are still performance manufacturers making cylinders over here (and selling then well) that can only make 17 PS, and require a primary ratio of 3.00 !

That's why I paid so much attention to making good torque (something a two stroke is good at) at low RPM.

This particular one is (in my opinion) a good example (my best of this type). There are other people here in europe making this (and more) sort of power from the same 133cc cast iron cylinder, it just involves ALOT of work (both on the cylinder, and the cases), and not many customers are willing to pay what it actually costs!

This attachment is from the same type of engine (but with a different pipe and different exhaust timing.....and from memory a 30MM carb....hence now revving to 10,000, and was also very "peaky"....something I am always keen to get away from particularly when dealing with 4 speed transmissions..... ( 2nd,3rd,4th gear "all gear runs" always have just that little bit more power (as you may well know) you can see the big "jump" between 3rd and 4th gear ratios!

I don't have an all gear run for that other cylinder on this computer, I hopefully have one at work (although the dyno had a new computer at the end of last year, so it may be a little hard)

Obviously the stuff I "specialise" in is reed valved piston windowed cylinders, but some of the things I learned from these engines has carried over well to the disc valved stuff as well..........

lance_nz

30th April 2009, 12:07

TZ350

30th April 2009, 12:37

Yes you did, sorry mate, I guess that proves the old saying "a pupil can't be taught untill he's ready to learn". Or in this case "an old dog can learn new tricks" I have got some heavier springs and will fit them.

.

speedpro

30th April 2009, 20:04

My MB sidecar engine had a Keihin 28mm carb, beautiful little carb. Every other engine has always had the old 32mm round slide Mikuni and even the same main jet.

TZ350

30th April 2009, 20:58

I am Feeling very depressed today. I have finally got a handle on Jennings Time-Area/Angle-Area chart and how to use it and its not looking good.

Gordon Jennings:- http://www.vintagesleds.com/library/manuals/misc/Two-stroke%20Tuner%27s%20Handbook.pdf down load it from here.

To use this chart you need to know the port open duration and the mean area of the port, which is roughly ¾ of the total port area.

Finding the “SPECIFIC ANGLE AREA” for the “DISC-ROTARY INTAKE” on my Suzuki GP125.

First, the inlet port is slightly bigger than the 24mm carb, port area = 5cm2.

Second divide 5cm2 by 125cc and get 0.04.

The inlet timing is, inlet opens 145 BTDC, closes 85 ATDC so the port open duration = 230 degrees.

Now 0.04 times 230 equals a “SPECIFIC ANGLE AREA” of 9.2.

A “SPECIFIC ANGLE AREA” of 9.2 just puts me into the 8,500 rpm region of the chart.

The only way to move to the 10,000rpm region is to increase the inlet timing and lose low-end torque or increase the size of the port but this is limited by the carb/port size relationship.

The 24mm carb limit has got my hands tied. A 28 would be good and a 32 just right.

This time-area.angle-area chart is a real easy way to figure if youve got enough port size and/or duration for the rpm you plan on using.
.

k14

30th April 2009, 21:08

The only way to move to the 10,000rpm region is to increase the timing and lose low-end torque or increase the size of the port but this is limited by the carb/port size.

The 24mm carb limit has got my hands tied. A 28 would be good and a 32 just right.
Well I think the only answer is to buy an fxr...

Sully60

30th April 2009, 21:13

Well I think the only answer is to buy an fxr...

Wash your mouth out!
Not enough cylinders<_<

SS90

30th April 2009, 21:17

I
A “SPECIFIC ANGLE AREA” of 9.2 just puts me into the 8,500 rpm region of the chart.

The only way to move to the 10,000rpm region is to increase the inlet timing and lose low-end torque or increase the size of the port but this is limited by the carb/port size relationship.

The 24mm carb limit has got my hands tied. A 28 would be good and a 32 just right.

.

Just to play devils advocate...is it possible to simply fit a bigger carb and test on the dyno (just for comparison)

I guess that is just academic, but it would be interesting aye!

10,000 RPM really is where you want to aim (aim my opinion), given the fact that you have an unsuitable gear box, but (as you are more aware than anyone that dammned 24mm carb really limits you!

My experience tells me that such an engine is possible (previous graphs), but, like I said, 28MM carbs (and up) are required!

PERHAPS (just a suggestion) you could reconsider your current cylinder, and simply make the engine (with different exhaust port timing) for low down power (with an ignition and pipe design) that simply allows for alot of "overrev", giving you not only an easier bike to ride, but also an engine that will have (similar) power characteristics to an FXR150.... (maybe):yes:

Yow Ling

30th April 2009, 21:17

Maybe start looking for a gp100 barrel

k14

30th April 2009, 21:21

Wash your mouth out!
Not enough cylinders<_<
We don't want everyone finding out how awesome cb's are! Leaves no spare parts for us :bash:

SS90

30th April 2009, 21:23

Maybe start looking for a gp100 barrel

That is a bloody good idea!

Sorry Teezee, but that may well be worth consideration!:calm:

TZ350

30th April 2009, 21:52

Links to Tech Stuff.

Gordon Jennings:- http://www.vintagesleds.com/library/manuals/misc/Two-stroke%20Tuner%27s%20Handbook.pdf

An assortment of Gennings Articles:- http://www.edj.net/2stroke/jennings

Graham Bell:- http://www.kreidler.nl/artikelen/performance-tuning-graham-bell/performance-tuning-graham-bell.pdf

Yamaha SAE Paper on Porting:- http://www.2stroke-tuning.nl/media/pdfjes/porting.pdf

Rate of Fuel Burn:- http://www.factorypro.com/tech_tuning_procedures/tuning_fuel_octane_vs_power.html

Reading Plugs:- http://www.dragstuff.com/techarticles/reading-spark-plugs.html

Engine formulas:- http://members.bellatlantic.net/~vze2p5sj/modelengines/engine1.htm

A Handy Coverter:- http://www.mr2ownersclub.com/converter.htm

Detonation:- http://www.factorypipe.com/t_deto.php

Dale Alexander. The Art Of Squishing Things Until They Make Power:-
http://www.aircooled-rd.com/default.asp?txtPage=squish1.htm
http://www.aircooled-rd.com/default.asp?txtPage=squish2.htm
http://www.aircooled-rd.com/default.asp?txtPage=squish3.htm

A preview of Kevin Camerons book “Sportbike Performance Handbook”:-
http://books.google.co.nz/books?id=LswdRd2Zm8YC&pg=PA85&lpg=PA85&dq=tz250+detonation+repair&source=bl&ots=zYYDz0MEyv&sig=pRPBbN00SOAg-wfME3O1YZCk9KU&hl=en&ei=Ve2tSb6iBYT06QO585zgBQ&sa=X&oi=book_result&resnum=1&ct=result#PPA81,M1

TUNING VESPA'S THE NORRIE KERR WAY.....
http://www.scooterhelp.com/serial/tuning.books.html

Crankcase delivery ratios and inlet timing for rotary disk motors:-
http://www.edj.net/2stroke/jennings/delivery_ratio.pdf

The effects of crankcase volume on the delivery ratio:-
http://www.edj.net/2stroke/jennings/crankcase_volume.pdf

Piston pin offset and what it means for extra power:-
http://www.motorcycleproject.com/motorcycle/text/cows-offset.html

4-Stroke stuff but very interesting about porting and combustion.
http://www.gofastnews.com/board/technical-articles/

Terminolagy:- http://www.2-stroke-porting.com/terminology.htm

Modifying a Suzuki open chamber to a squish head:- http://www.ozebook.com/compendium/t500_files/morgan/head.htm

.

TZ350

30th April 2009, 21:58

Just to play devils advocate...is it possible to simply fit a bigger carb and test on the dyno (just for comparison)

The problem with that is the whole inlet tract and port have to be reworked to suit the larger carb as the area of the port window needs to be just a whisker bigger than the carb.

A complete 100cc engine is starting to look like a good idea.

.

SS90

30th April 2009, 22:13

The problem with that is the whole inlet tract and port have to be reworked to suit the larger carb as the area of the port window needs to be just a whisker bigger than the carb.

A complete 100cc engine is starting to look like a good idea.

.
Yea, while I feel for all your hard work (and Thomas's....) with what you have learned from the 125, to apply it to a 100 would be quite amazing (and you could water cool the head as well)...... In THEORY you should be able to make more peak power than an MB100 (but alas, you get "fingered" by that transmission again), so making the bike rideable (with port timings to to extract that power might be hard work (but certainly possible).

Don't give up though.....not everything about two stroke tuning can be found in a book written in the 70's......:gob:

TZ350

1st May 2009, 22:42

Well I think the only answer is to buy an fxr...

I would buy a XL100 first and supercharge it, :eek: then your FXR's would be in real trouble. :bleh:

Supercharged Honda 50 http://www.elsberg-tuning.dk/the%20bikes.html

Superchargers.

The smog pump - cheap and plentiful. Used on automobile engines since late sixties.
The Aisin AMR300. From Subaru Kei- car - 660cc supercharged citycar.
The KF Max10- 25. American aftermarket blower.
The Hansen V12. Made especially for supercharging Kart- engines from 5- 20hp.

Thanks to TerraRoot for his post on the Blown FXR thread.

.

xwhatsit

1st May 2009, 23:39

I would buy a XL100 first and supercharge it, :eek: then your FXR's would be in real trouble. :bleh:

Supercharged Honda 50 http://www.elsberg-tuning.dk/the%20bikes.html

.
I've seen that before. Very impressive -- same motor as in my little Honda C50, which tops out around 65kph. He says he hit 142kph. Stock cam!

TZ350

1st May 2009, 23:47

I've seen that before. Very impressive -- same motor as in my little Honda C50, which tops out around 65kph. He says he hit 142kph. Stock cam!

The way to get drive out of a supercharged 4-stroke is to use the stock or milder than stock cam. As you are blowing the air in and don't need all that super cammy stuff.

.

koba

2nd May 2009, 00:15

I would buy a XL100 first and supercharge it, :eek: then your FXR's would be in real trouble. :bleh:

Apparently it has been done before...
As far as I understand (so I'm probably wrong!) one major problem with supercharging (With a positive displacement blower) small bikes is the clearances in a blower stay more or less the same regardless of size so the smaller the blower the greater the pumping loss % or somthing like that anyway...

I did a bit of research on the Aisin AMR300 and AMR500 as I was looking using one on my VW Beetle. I think a 100 would have a fair ammount of trouble spinning it!

I think (Just as an idea) if you really did want to play with such a thing the compressor side of a tiny turbo would probably be worth looking long and hard at.

A. Graham Bell also has a great book on forced induction tuning.

Edit: Ahh, I see the guy in that article cut his blower down!
Smart bastard!

Buckets4Me

2nd May 2009, 07:28

I think (Just as an idea) if you really did want to play with such a thing the compressor side of a tiny turbo would probably be worth looking long and hard at.

normal Turbo spins to about 140,000 rpm not the 11,000-15,000rpm of a small 4 stoke :crazy:

would have to gear it up heeps

Yow Ling

2nd May 2009, 08:23

A hyperbar engine would solve all the lag issues. But create new ones

speedpro

2nd May 2009, 10:19

I would buy a XL100 first and supercharge it, :eek: then your FXR's would be in real trouble. :bleh:

Supercharged Honda 50 http://www.elsberg-tuning.dk/the%20bikes.html

Superchargers.

The smog pump - cheap and plentiful. Used on automobile engines since late sixties.
The Aisin AMR300. From Subaru Kei- car - 660cc supercharged citycar.
The KF Max10- 25. American aftermarket blower.
The Hansen V12. Made especially for supercharging Kart- engines from 5- 20hp.

Thanks to TerraRoot for his post on the Blown FXR thread.

.

I have a new/refurbished smog pump off a big block chev.. I also have a reconditioned supercharger off a 660cc car, and I have a little tiny IHI turbo off a 660cc car as well. If you are serious about making a blown bucket you can have one. As long as I get a ride. The supercharger displaces 300cc/revolution supposedly.

TZ350

2nd May 2009, 15:20

I have a new/refurbished smog pump off a big block chev.. I also have a reconditioned supercharger off a 660cc car, and I have a little tiny IHI turbo off a 660cc car as well. If you are serious about making a blown bucket you can have one. As long as I get a ride. The supercharger displaces 300cc/revolution supposedly.

Now I am torn, I have a RG50 rolling chassis setup with TZR wheels and was going to make a RG50 F5 racer. But a supercharged 100 is becoming realy compelling. I would need some Honda SL XL 100 engines and engine parts though.

In the 70s/80s I had quite a bit of experiance with Roots type and Shoric vane superchargers and have an idea of their potential. I would be interested in talking with you about the supercharger from the 660cc car.

Even if I make a supercharged 100, I am not planning on giving up on the two stroke.

.

Kickaha

2nd May 2009, 16:27

I would need some Honda XL 100 engines and engine parts though.
.

Try Diesel Pig he has one I don't think he is going to use

craisin

2nd May 2009, 19:38

talking up a storm :zzzz:
just to keep warm

TZ350

2nd May 2009, 20:14

talking up a storm :zzzz:
just to keep warm

Yep the excitment of talking up a storm sure keeps you warm. Looking for a Honda CL, SL, XR motor and/or motor parts.

.

TZ350

2nd May 2009, 22:41

Tomas thinks we have got a little off track here. He said that as the current GP125 is making about 20ps at 11,000 then the inlet port must be passing some air. He suggested we port a cylinder to the same specs as the RS125 Cylinder and the current pipe that was made to the old RM125 specs is designed to peak at about 10,000rpm. But the current 81 ATDC Exhaust timing is pushing the peak to 11,000.

He pointed out by changing the exhaust timing and dropping 1,000rpm we may not lose too much off the top if any by getting the power peak closer to the optimum revs for the inlet port-time/area constrant in Jennings graph. Also with the milder modern porting we will probably pick up a lot broader power band and even more so if we go on to make a new pipe in the modern style.

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

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

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

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

.

craisin

3rd May 2009, 04:23

well i have a air-conditioning compressor off a yank tank i presume
i bought off a guy i met at a swap meet for $10 to make a compressor as i bought an older type tire changing machine too.
i sold the tire machine maybe 15 years ago.
I have had thoughts of supercharging bike engine with it but it has a oil sump and this other guy had one the same on his V8 powered landcruiser to pump up tires
that guy told me he had to use a special oil with it as your liable to get explosions.
it has a electric clutch on it.
I would think it was more suited to a sidecar or trike as the dont get the extreme angles that bikes get
you can have it if it cheers you up PM me if your keen:niceone:

SS90

3rd May 2009, 10:46

TZ350

3rd May 2009, 11:01

I'll wonder if he has a new exhaust design as well;)

How many million people are there is Siagon? and how many motor scottors? I think he prety much understood all this before but was waiting for me to catch up. He's a clever chap, he managed to get to Indonesia when he was 13 and worked as an apprentice motorcycle mechanic, later returned to Vietnam to work with his father hand making watches and clocks before coming to New Zealand. He speeks several languages.

Yes he has a chamber design to try but everything takes time. The plan is:- Test bike as is for a base line and try a retarding ignition, modify and test the new cylinder with original RM-Spec pipe. Other projects are a new pipe and investigating alternative fuels like Shell 98, Mobile 1000 and Gull, straight and blended with Av Gas. Looking to retard the ignition some more and for better throttel response. Later when the motor is stripped to fit the new 1st gear we will be able to raise the primary compression.

.

SS90

3rd May 2009, 11:11

How many million people are there is Siagon?

Yes he has a chamber design to try but everything takes time. The plan is:- Test bike as is for a base line and try a retarding ignition, modify and test new cylinder with original RM-Spec pipe. Other projects are a new pipe and investigating alternative fuels like Shell 98, Mobile 1000 and Gull straight and blended with Av Gas. Looking to retard the ignition some more and for better throtel response.

.

Please don't take it personally Teezee, it's not aimed at you. I just read in one post from you what I have been writing (with broad hints rather than instructions) for the last 100 posts or so.

I have had a 2 designs STOLEN from me by some "dudes" in Saigon (and so have some very very very clever people her in Germany) and after a while it has gotten hard to swallow.

The guy I mentioned simply said to me

" We copy everything"

Lets get real though, is it really likely that some "guys" in Saigon came up with the techiniques you just photographed?

NOT REALLY.

Rant over anyway.

I will be interested to see what Thomas come up with......... :whistle:

TZ350

3rd May 2009, 11:35

Lets get real though, is it really likely that some "guys" in Saigon came up with the techiniques you just photographed?

NOT REALLY.

They did chase the bigest military power on earth out of their country with little more than sharpend bambo sticks. It would be a mistake to under estimate them.

They do have access to the net and can read SAE papers in English and French no problem. And there are a gazillion motorscottors to practice on.

Tomas is probably more concerned about you stealing his ideas for profit as although you have coverd a lot of material that is in the public domain you have shared very little of substance of your own.

He has consistantly shown what, why and how of every thing he has done, its the Bucketeer way.

.

Buckets4Me

3rd May 2009, 11:49

lets not start another war :argh:
:angry2: (sharp bambo stick)

:bash: ( U.S.A U.S.A )

BOOM........................................

watch out they will send all there PIG farmers (With colds) to see you.
and a few surviving chicken farmes for good measure

TZ350

3rd May 2009, 12:09

How much does the air in a 100 foot cube weigh?

The answer is in the next post.
.

TZ350

3rd May 2009, 12:11

38 tones thats right thirty eight tones and thats why inertia and the ram effect of pipes and ports is so effective.

Mostly 4-stroke stuff but worth a read:- http://www.gofastnews.com/board/technical-articles/1130-porting-school-7-power-port-volumes.html.

A sample from the page:-

So air is heavy – if we add to this the fact that the energy is equal to half M(mass) times V(velocity) squared (1/2MV^2) we can see that when port velocity goes up the port energy goes up far faster and when port velocity drops the port energy drops far faster. Putting that into prospective if a port is made 20% too big the port energy drops by 44%. In basic terms that equates to a 44% drop in the ports ability to ram a cylinder by means of it’s velocity derived momentum. When it comes to combating reversion, especially at low speed port velocity is very effective. Kill the velocity below a certain level and you effectively kill torque at the lower rpm levels while not necessarily garnering any power advantages at the top end.

With the limitation of a 24mm carb and the need for punch out of the corners in Bucket racing I am very interested in port velocity.

Scroll to the bottom of the page for other aspects of porting and combustion chamber dynamics. http://www.gofastnews.com/board/technical-articles/1130-porting-school-7-power-port-volumes.html.

.

SS90

3rd May 2009, 12:16

Tomas is probably more concerned about you stealing his ideas for profit as although you have coverd a lot of material that is in the public domain you have shared very little of substance of your own.

He has consistantly shown what, why and how of every thing he has done.

.

Now Teezee, I hope you just wrote that last post out of anger, and don't really mean what you wrote....

ME "stealing" Thomas's ideas...

WHAT IDEAS WOULD THAT BE?

(I can't find an emoticon on this site that conveys how I feel at that statement)

I have been to saigon. I have seen FIRST HAND what they do, and how they do business.

Erm.... Have you ever seen a fake rolex watch from anywhere other than China or VIETNAM?

We got off to a bad start, but lately I was under the impression that we had all "left our ego's at the door".

Clearly not!

teezee, please post All "Thomas's" planned specs (port angles, heights, pipe dimesions etc)

I'll tell you who (most likely) designed them.

This is the same guy who had the ignition too advanced, and the main jet too rich, as well as the exhaust port timing totally up the cock yet he is able
to come back from Vietnam (a place that over the last few years (in the Vespa tuning scene) has gained a well deserved reputation for stealing OUR designs, remaking them (exhausts, cylinders) and selling them for half the price!), and when he returned, he MIRACULOUSLY knew all about it (but he was just keeping that "hush hush")

teezee, if you think I have learned ANYTHING from your thread (other than the Saigon stealing machine has hit godzone) then mate, you are sadly mistaken.

I have given you some real gems on what directions you should be heading in (primary compression,scavenge patterns,compression ratios,transfer shrouding,ignition timing)

I am bitterly dissapointed with your attitude now Teezee.

ME stealing Thomas's ideas indeed. (again, WHAT IDEAS?)

TZ350

3rd May 2009, 12:25

teezee, please post All "Thomas's" planned specs (port angles, heights, pipe dimesions etc)

I'll tell you who (most likely) designed them.

Your arrogance knows no bounds.

.

TZ350

3rd May 2009, 12:28

This is the same guy who had the ignition too advanced, and the main jet too rich, as well as the exhaust port timing totally up the cock.

It was myself who had the bike setup like this. I told him what I wanted, he did suggest things that I didn't understand or was to impatent to be bothered with at the time and in the end the customer, "me", is allways right, right!

.

TZ350

3rd May 2009, 12:30

teezee, if you think I have learned ANYTHING from your thread (other than the Saigon stealing machine has hit godzone) then mate, you are sadly mistaken.

I have given you some real gems on what directions you should be heading in (primary compression,scavenge patterns,compression ratios,transfer shrouding,ignition timing)

I am bitterly dissapointed with your attitude now Teezee.

ME stealing Thomas's ideas indeed. (again, WHAT IDEAS?)

We got off to a bad start, but lately I was under the impression that we had all "left our ego's at the door".

Clearly not!

You realy are behaving badly. Please continue to leave your ego at the door.

SS90

3rd May 2009, 12:33

.

This is Thomas a Vietnamese race mechanic, you know that place where they have all those hot 50's and 125's are big bikes.

Thomas, ESE's Race Team's Tuner is fettling number 9. adjusting the port timing for Taupo.

Its hard to see but he has taped a degree wheel to the magneto flywheel so he can mark out the exhaust port height he wants.

None of this raise the port 3.5mm for a gazillion HP nonsense. He knows what timing he needs and sets the crank position there before marking the port and then doing the hells death port job that we all dream of.

You should see him setting up a carb. Talk about pain staking, he starts with a main jet so big the bike floods at about half throttle (apparently this proves the oriface of the needle/needle jet combo is big enough) and then he slowly step by step works back until it runs clean.

Most people start at the bottom with a carb and work up, He starts at the top and works backwards.

Never seen him blow one up. But then he is intelligent with the throttle and does not ring its neck when the engine is in distress.

Boy o Boy am I Looking forward to Taupo.

.

Oh, sorry for the confusion. Don't take this the wrong way Teezee, but you would see it the same as me if I was stealing your ideas (well, not only mine, but more your friends and peers in the industry.) I don't aim this at YOU (or even Thomas) but just think about the reality of the situation.

This particular subject is very raw in the industry I work in. (It get discussed over here ALOT!)

Europe.

Vietnam.

TZ350

3rd May 2009, 12:47

Yes you are probably right, we don't live in Europe so don't realy know how it is.

I have worked with a lot of people in my time and Tomas is one of those people you just have to admire. One does not meet to many of those in life.

Yes you have put out some gems, I am sure Tomas is glad that at least I got the idea eventualy.

You have to respect Tomas for being able take (put up with) my ideas and build something that didn't immediatly blow up.

.

SS90

3rd May 2009, 13:01

Yes you are probably right, we don't live in Europe so don't realy know how it is.

I have worked with a lot of people in my time and Tomas is one of those people you just have to admire. One does not meet to many of those in life.

.

Like I say, nothing personal against you or Thomas.

There are some really nice guys (some of whom work for companies like KTM and Huskvarna) over here that have had their designs copied "over there" (including one guy who named the exhaust after his son (Franz)), and sold them well, only to find that they where later offered on Ebay for €180...with the same Brand name!

There are dozens of stories like that, but PLEASE remember that the techniques you are now using where developed people in this part of the world..... I know that for a fact.

Does Vietnam have a factory 125GP team?

No.

I hope we can end this childish shit now!

speedpro

3rd May 2009, 14:24

Kickaha

3rd May 2009, 14:48

You realy are behaving badly. Please continue to leave your ego at the door.

He's always behaved badly, imagine riding a bucket two up through Otira gorge the filthy law breaker

As regards his two stroke tuning ideas the fiddler would have taught him everything he knows :bleh:

Buckets4Me

3rd May 2009, 16:45

Does Vietnam have a factory 125GP team?

No.

I hope we can end this childish shit now!

no but the CHINES do. Did they steal that from APRILLA DERBIE ?????

you make a design that works people coppie it how the world goes
you cant tell me the GERMANS never coppied anything ???

just ask the AMERICANS they steel everything patten it and call it there own
how the hell did they get to the moon ???????? stole it all
Russians did the same thing

now stop sulking and get on with making MY engine faster
(and I dont care where you steel the idears from) just dont ask me to pay for them. This is buckets after all

Buckets4Me

3rd May 2009, 16:46

Me personally I paid Wobbly to design my motor but I'm not sure where he got the ideas from, someone in Europe probably. I'm gonna ask him.

He stole them from ME!!!!!!!!!

now pay up please

1 mILLion DOllars.
or I set minime onto you

TZ350

3rd May 2009, 17:04

There are dozens of stories like that, but PLEASE remember that the techniques you are now using where developed people in this part of the world..... I know that for a fact.

I hope we can end this childish shit now!

The techniques being used now look remarkably like those in the Yamaha SAE paper from about 1990 I posted earlier and the examination of some cylinders, Suzuki RM125 and Honda RS125 being two of them, all this information I have posted as I have gone along.

As for the childish shit, any time you want to bring some maturity to this thread it would be welcome.

.

TZ350

3rd May 2009, 17:11

Me personally I paid Wobbly to design my motor but I'm not sure where he got the ideas from, someone in Europe probably. I'm gonna ask him.

Speedpro you are being subtle again, I can tell! :yes:

When I worked at the same place as him for a while, I was going to ask, but then I noticed the extensive libary. Any way to ask would have only invited a crack from one of Waynes walking sticks.

That bike he built at Buckleys did run at Top International GP level, it was built from the ground up and started with a clean sheet of paper, yep it was a Wobbly design for sure.

.

Kickaha

3rd May 2009, 17:51

That bike he built at Buckleys did run at Top International GP level
.

Are you sure about that?

It failed to qualify at most of the rounds and was slower than the top NZ Superbikes

TZ350

3rd May 2009, 18:38

Are you sure about that?

It failed to qualify at most of the rounds and was slower than the top NZ Superbikes

I know in real terms it was not that great. Did it qualify at any round??? But it was up there, and it was a game effort.

.

Kickaha

3rd May 2009, 18:42

I know in real terms it was not that great. Did it qualify at any round??? But it was up there, and it was a game effort.

.

It finished 18th at the Spanish GP in 99, but missed qualifying at 3 out of the first 4 races it entered

TZ350

3rd May 2009, 18:50

Because the future may be 100cc I am starting to research it. Converting a RG150 water cooled to a 100cc, I have heard people say they had problems with the transfers and I suspect the problem was port/duct velocity.

From the Porting School:-

"So what we can say at this point is that a significant proportion of an engines flow through depends on port velocity as well as the generation and utilization of pressure pulses. This means even a little excess in terms of port area can hurt power even though it may, on the flow bench at least, flow better."

More here:- http://www.gofastnews.com/board/technical-articles/1130-porting-school-7-power-port-volumes.html

.

SS90

3rd May 2009, 20:41

He's always behaved badly, imagine riding a bucket two up through Otira gorge the filthy law breaker

As regards his two stroke tuning ideas the fiddler would have taught him everything he knows :bleh:

Oh, there is more than the Otira Gorge (some secrets we never told!)....you filthy GP engine stealing "GO CARTER":whistle:

As for Fiddlers lessons, my favourite classes of his where

"catching a ride down Manchester street on a Range Rover":woohoo:

and (my second fave)

"Love thy Neighbour":hug:

GN125R indeed!:laugh:

Now, go change some tyres!

SS90

3rd May 2009, 20:56

I think we might need to make a list of the countries with people who may be able to think of a way of making a small 2-stroke go faster plus a list of people who definitely can do that, and where they live. We can then reliably slag anyone else's ideas and also accuse them of nicking the above mentioned list of peoples original ideas. Me personally I paid Wobbly to design my motor but I'm not sure where he got the ideas from, someone in Europe probably. I'm gonna ask him.

Quite right speedpro, and certainly so much of the technology that the Japanese developed is being used today (as, in reality, the Japanese have stopped developing two strokes)

However, my point is that (rather than going through all my posts, to prove it) Thomas come back from Nam, and all of a sudden, Teezee starts "coming up with all these good ideas (I mentioned months ago "look at Japanese 125cc cylinders", and months ago, Teezee asked me "for clearer hints", and only last week, I told him "Honda RS125"

Lately, I even posted pictures of my latest work.

Basically, Logically, realistically, this level of two stroke tuning DID NOT COME FROM VIETNAM...it's all stuff I have mentioned here prevoiusly, then, all of a sudden I am "stealing Thomas's ideas"

WHAT IDEAS TEEZEE?

A peaky, high exhaust port duration, over advanced, too rich, incorrect primary compression rato'd, shrouded transfered,not retarding ignition two stroke with an exhaust design than was on the Millenium Falcon?

Naaa, Been there, done that. Years ago.

I am 100% confident that Wobbly will not say " Oh yea, we learned all our knowledge from Vietnam"

Think about it.

if Thomas knew what you are now posting in NOVEMBER of last year, he would not have built the peaky shit box he did before I started posting

Chambers

3rd May 2009, 21:05

SS90 there is something disturbingly odd about you.

SS90

3rd May 2009, 21:10

Ok. I was at Johns to dyno the bikes and yours turned out to be the best!!!! OK. :angry2: and mine was the worst. :crybaby:

All four bikes were run up and it turned out that the more Hotted-Up they were the worse they performed. :pinch:

As the testing went on there were a few more surprises.

Many thanks to John for his time and help.

.

Really? I can't believe it!

bucketracer

3rd May 2009, 21:18

SS90

3rd May 2009, 21:31

I have watched the posts with interest. I have seen SS90 push crankcase compresion ratios and hint at the more modern way to the point of being overbearing, with a bit of a "bee in the bonnet" hysteria.

TZ has followed up and done his own research, sharing the results with us all the way. Who knows where TZ found Tomas but you can bet there were more people than just Wobbly working on the BSL project.

Hmmm, I'm not 100% sure what you point is there, and this really has gone out of control.

I have given quite a few good hints here, and, in my opinion (and others) Teezee is giving Thomas all the credit (not that I did all that in the pursuit of glory), I just read some very wrong information and was offering advise (correct advise) based on experience.

Now I'm being accused of "stealing Thomas's ideas"

What Ideas?

A peaky, high exhaust port duration, over advanced, too rich, incorrect primary compression rato'd, shrouded transfered,not retarding ignition two stroke with an exhaust design than was on the Millenium Falcon?

Did that when I was 15. (as have so many people before me)

bucketracer

3rd May 2009, 21:38

Basically, Logically, realistically, this level of two stroke tuning DID NOT COME FROM VIETNAM...it's all stuff I have mentioned here prevoiusly, then, all of a sudden I am "stealing Thomas's ideas"

Actualy your input has never been more than reciting the basics and some vague hints. I expect that TZ in asking for clearer hints was just trying to draw you out to see if you actually had any real "stuff" to offer.

As for your pictures, cutting gully ports in a barrel is mentioned in Jennings book and probably Bells too.

You can't claim ".it's all stuff I have mentioned here prevoiusly," as you have not actualy mentioned anything of substance like TZ has, your hints are just that hints, vauge things that can be used later, for "I told you so" or "That was my idea".

TZ's done the research, your just trying for the glory.

SS90

3rd May 2009, 21:49

Actualy your input has never been more than reciting the basics and some vague hints. I expect that TZ in asking for clearer hints was just trying to draw you out to see if you actually had any real "stuff" to offer.

You can't claim ".it's all stuff I have mentioned here prevoiusly," as you have not actualy mentioned anything substantial or specific.

TZ's done the research, your just trying for the glory.

Really?

Just reciting the basics?

And, pray tell good fellow, what have YOU offered this thread?

Because, of course, you knew it all didn't you.

Because you think a A peaky, high exhaust port duration, over advanced, too rich, incorrect primary compression rato'd, shrouded transfered,not retarding ignition two stroke with an exhaust design than was on the Millenium Falcon

is a good engine huh?

speedpro

3rd May 2009, 21:51

Chambers

3rd May 2009, 22:04

A peaky, high exhaust port duration, over advanced, too rich, incorrect primary compression rato'd, shrouded transfered,not retarding ignition two stroke with an exhaust design than was on the Millenium Falcon

SS90 you have posted the above three times on this page, why do you need to do that. What has TZ done to you, that you need to react so badly? Its OK that he is posting usefull stuff, get over it.

Virago

3rd May 2009, 22:12

The Mods don't like to step into such worthwhile technical threads, but this is getting a bit silly.

Can everyone please move on from this childish bickering.

Cheers.

TZ350

3rd May 2009, 22:45

As clever as TZ is, he has been avoiding a few of the basics, like a good ignition and doing a few dyno runs. That has changed now which will only bring bad news for the rest of us. In attempts to gain power a few of us have headed down the blind alley of making ports bigger etc. TZ is taking a more considered approach, one which it's taken me a few years to cotton on to. Hopefully he will be too old to ride it properly once it is all sorted. :Pokey:

Yep I am pretty convinced about dyno's now for sure. We just didn't get around to building one at work as quick as I hoped, it all just takes so much time. I am lucky to have Tomas's help with getting things done on the bike, now that he is back we should start getting somewhere.
.

F5 Dave

4th May 2009, 10:10

Not wanting to knock the BSL too much I did lose an awful lot of respect for it seeing it toasted by GSXR600s at Wanganui. They did give credit to TSR software for pipe design, but that is only a starting point, you need to know the 'right' answers to the questions for imputing data.

Here's a pic I took last month, it does look a nice bit of kit.

TZ350

4th May 2009, 18:08

Yes its beautifully made, but fortune sure did not smile on the BSL. Given more time I am sure they would have got somewhere with it.

But it makes me appreciate Buckets where I can afford to get totaly involved in the development of a bike because racing and development is so much more affordable in F4 and F5.

.

Yow Ling

4th May 2009, 22:00

Heres something to try when the big gains have already been made http://www.iwt.com.au/cryogenics.htm

drop your engine in liquid nitrogen. Dyno charts to prove the theory

saxet

4th May 2009, 22:31

Someone was trying to tell me to spray a fine jet or several jets of a cold gas onto the head:eek5:....dunno how it fits in the rules..no mention of gas cooling.:cold:

TZ350

4th May 2009, 22:45

Someone was trying to tell me to spray a fine jet or several jets of a cold gas onto the head:eek5:....dunno how it fits in the rules..no mention of gas cooling.:cold:

Good thinking but the rules are specific "Air Cooled" for a 125 2-stroke but I guese that could be cold air in a bottle.

.

TZ350

4th May 2009, 22:53

Heres something to try when the big gains have already been made http://www.iwt.com.au/cryogenics.htm

drop your engine in liquid nitrogen. Dyno charts to prove the theory

This is a scrape from that page:-

In this ’ultimate’ test a standard Yamaha KT100S kart engine was used, and after a complete rebuild and normal running-in period, it was dyno tested to give an output as in the following chart named #AJS.101. For peace of mind the carby was removed from the engine before the all-in cryogenic treatment, and the crankshaft seals were replaced after the treatment. The treated engine was then dyno tested and the results obtained are named #AJS.111.

I presume they dunked the whole engine in liquid nitrogen. The boil off would be spectacular.

.

F5 Dave

5th May 2009, 09:27

Hmm, maybe if he'd acted quickly enough Mike could have Cyrogenically frozen his MB engine until a cure could be found.;)

speedpro

5th May 2009, 18:30

I've been talking to your wife and we agree that you should be frozen, pending a cure.

TZ350

9th May 2009, 07:39

we need to examine the impact the combustion chamber has on an engine.

Abnormal combustion, better known as detonation, is more likely with a slow combustion process since it allows time for an additional flame front to start.

And a combustion chamber that has a fast burn rate is essential to increase the engine's octane tolerance.

Air cooled Suzuki motor X bikes that I have had a look at, all had open combustion chambers without any squish and about 22 RWHP. Kawasaki and Yamaha much the same but with squish bands. But the Suzuki was known for the width of its power band.

The jury is still out in our camp over squish/non-squish heads for our buckets.

But it is remarkable the difference it made to the ignition timing requirements of our bikes.

We can see from the ignition timing requirements the difference in burn rates between the open and squish type combustion chambers on our bikes.

I am hoping to get my bike with the squish chamber to Henderson Yamaha's dyno so I can get a printed dyno sheet so we can compare the torqe curves to the other non squish engines.

Scraped from:- http://www.highperformancepontiac.com/tech/0209hpp_engine_combustion_chamber/index.html

"The problem is that when an engine of this dimension is running at 3000 rpm, there is only a window of 10 milliseconds for the combustion event to take place. Obviously another force must be at work because we all know that a gasoline engine can operate at speeds substantially higher than 3000 rpm. The key is to increase the burn velocity.

It has been established that the flame in an engine travels across the bore at a rate of 10-25 m/s. This is substantially faster than the velocity stated earlier, but it is the reason why gasoline can be used as a motor fuel. To increase burn velocity, turbulence needs to be introduced to the combustion event."

In an engine, this is accomplished by the induction and compression process along with the design of the combustion chamber. During pre-mixed combustion, the effect of the turbulence is to break up or wrinkle the flame front, creating burnt gases in the unburned region, and vice versa. This effectively increases the flame front area and speeds up combustion.

The rest of it can be read here:- http://www.highperformancepontiac.com/tech/0209hpp_engine_combustion_chamber/index.html

A common analogy that compares an engine to an air pump establishes the fact that the more air pumped, the greater the output. This cannot be denied but it's a one-dimensional statement ignoring the fact that without an efficient combustion event, the air by itself can do nothing. For this reason we need to examine the impact the combustion chamber has on an engine.

Abnormal combustion, better known as detonation, is more likely with a slow combustion process since it allows time for an additional flame front to start.

A combustion chamber that has a fast burn rate is essential to increase the engine's octane tolerance at higher compression ratios.

.

TZ350

9th May 2009, 08:42

Links.

Terminolagy:- http://www.2-stroke-porting.com/terminology.htm

MSV Mean Squish Velocity Calculator:- http://myweb.tiscali.co.uk/teamsparrow/cylinderheadsv2_3.xls

Simulation video clips of 2-stroke scavenging:-
http://video.google.com/videosearch?client=firefox-a&rls=org.mozilla:en-GB:official&channel=s&hl=en&q=two+stroke+scavenging&um=1&ie=UTF-8&ei=-EUFSunlCcjJtgeG2K2XBw&sa=X&oi=video_result_group&resnum=4&ct=title#

A catalog search engine, pistons, rod kits etc.
http://www.who-sells-it.com/r/mahle-pistons-2-stroke.html

Using only one ring:- http://www.vintagesleds.com/library/manuals/misc/jennings/l-ring_effect.pdf

The effects of higher compression ratios in a 2-stroke:-
http://www.vintagesleds.com/library/manuals/misc/jennings/higher_compression.pdf

From, Yow Ling. www.zeeltronic.com has fully programmable cdi's about 100 euros.

Stan Stevens RGV Tuning:- http://www.stanstephens.com/rgv.htm.

A MacDizzy Blaster Engine Rebuild with Photos:- http://www.macdizzy.com/1989hhopup.htm

MacDizzy's:- http://www.macdizzy.com/

Modifying a Suzuki open chamber to a squish head:- http://www.ozebook.com/compendium/t500_files/morgan/head.htm

Dispelling 2-stroke tuning myths:- www.fatbaq.com/RS125_dispellingmyths.doc

Gordon Jennings:- http://www.vintagesleds.com/library/manuals/misc/Two-stroke%20Tuner%27s%20Handbook.pdf

An assortment of Gennings Articles:- http://www.edj.net/2stroke/jennings

Graham Bell:- http://www.kreidler.nl/artikelen/performance-tuning-graham-bell/performance-tuning-graham-bell.pdf

Yamaha SAE Paper on Porting:- http://www.2stroke-tuning.nl/media/pdfjes/porting.pdf

Gold Mine 1:- http://www.2stroke-tuning.nl/media/

Rate of Fuel Burn:- http://www.factorypro.com/tech_tuning_procedures/tuning_fuel_octane_vs_power.html

Reading Plugs:- http://www.dragstuff.com/techarticles/reading-spark-plugs.html

Engine formulas:- http://members.bellatlantic.net/~vze2p5sj/modelengines/engine1.htm

A Handy Coverter:- http://www.mr2ownersclub.com/converter.htm

Detonation:- http://www.factorypipe.com/t_deto.php

Dale Alexander. The Art Of Squishing Things Until They Make Power:-
http://www.aircooled-rd.com/default.asp?txtPage=squish1.htm
http://www.aircooled-rd.com/default.asp?txtPage=squish2.htm
http://www.aircooled-rd.com/default.asp?txtPage=squish3.htm

A preview of Kevin Camerons book “Sportbike Performance Handbook”:-
http://books.google.co.nz/books?id=LswdRd2Zm8YC&pg=PA85&lpg=PA85&dq=tz250+detonation+repair&source=bl&ots=zYYDz0MEyv&sig=pRPBbN00SOAg-wfME3O1YZCk9KU&hl=en&ei=Ve2tSb6iBYT06QO585zgBQ&sa=X&oi=book_result&resnum=1&ct=result#PPA81,M1

TUNING VESPA'S THE NORRIE KERR WAY.....
http://www.scooterhelp.com/serial/tuning.books.html

Crankcase delivery ratios and inlet timing for rotary disk motors:-
http://www.edj.net/2stroke/jennings/delivery_ratio.pdf

The effects of crankcase volume on the delivery ratio:-
http://www.edj.net/2stroke/jennings/crankcase_volume.pdf

Piston pin offset and what it means for extra power:-
http://www.motorcycleproject.com/motorcycle/text/cows-offset.html

4-Stroke stuff but very interesting about porting and combustion.
http://www.gofastnews.com/board/technical-articles/

Supercharged Honda 50 http://www.elsberg-tuning.dk/the%20bikes.html

Drop your engine in liquid nitrogen:- http://www.iwt.com.au/cryogenics.htm includes dyno charts to prove the theory. Thanks Yow Ling.

The Big Tuning Manual from Piper Cams:- http://www.bgideas.demon.co.uk/tmanual/ it talks about combustion chamber shape and swirl patterns, and are PDF's that can be down loaded.

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TZ350

9th May 2009, 09:19

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This is a must see! Lots and Lots of pictures. 14 pages.

MacDizy Blaster Engine Rebuild with Photos:- http://www.macdizzy.com/1989hhopup.htm

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TZ350

9th May 2009, 09:35

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Flat-Top VS Higher Crowned Pistons:- http://www.2strokeheads.com/tech3.htm

Ski Doo Tech Articals:- http://www.2strokeheads.com/tech.htm

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TZ350

9th May 2009, 09:37

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Stan Stevens Tuning.

The combustion chamber domes use the latest 2-stroke Grand-Prix technology with a dual angle squish area and a toroidal shaped combustion area.

http://www.stanstephens.com/rgv.htm.

Wiseco Pistons: We have been testing/ developing Wiseco Pistons for the RS250/RGV. The pistons are forged instead of cast, are incredibly strong and last approx 3 times as long in race conditions. They are lighter than standard and are a direct replacement for the genuine pistons. We have had a batch of pistons made by Wiseco exclusively for SS Tuning.

The RGV pistons have a flat top.

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TZ350

9th May 2009, 10:03

The 2008 Yamaha YZ125 uses a flat top piston which matches the specially designed combustion chamber, designed for maximum power delivery and achieves a more complete burn at higher rpms for exceptional power output. http://www.totalmotorcycle.com/photos/2008models/2008models-Yamaha-YZ125-2Stroke.htm

Yesss the 2008 YZ125 uses a flat top piston just like I do in my bucket.

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TZ350

9th May 2009, 10:18

A New Zealand company has redesigned the two-stroke combustion engine with the intention not only of overcoming the shortcomings of the conventional sliding-piston two-stroke engines, but also to produce a combustion engine that can better exploit hydrogen as a fuel. http://www.greencarcongress.com/2006/03/pivotal_piston_.html

Hows that for different!!!!! It looks like the underside of the piston sweeps a much larger volume than the piston side does. So the motor looks like it is supercharged like the old DKW racers were.

And a water cooled piston no less!!!!

Something different and made in NZ.

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TZ350

9th May 2009, 10:36

Not a 2-stroke I think but a very clever piece of German kit.

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Kickaha

9th May 2009, 10:43

Hows that for different!!!!! It looks like the underside of the piston sweeps a much larger volume than the piston side does. So the motor looks like it is supercharged like the old DKW racers were.

And a water cooled piston no less!!!!

Something different and made in NZ.

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http://www.pivotalengine.com/

Thats been around for a while I remember seeing it at Ruapuna on display at at Race meeting quite some time ago

I see it says 02 on one part of the site

TZ350

9th May 2009, 10:51

TZ350

9th May 2009, 11:54

http://www.pivotalengine.com/

Thats been around for a while I remember seeing it at Ruapuna on display at at Race meeting quite some time ago

I see it says 02 on one part of the site

Did they have it running? I see the power output is not that high. Still clever stuff though.

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TZ350

9th May 2009, 12:47

The effects of higher compression ratios in a 2-stroke:-
http://www.vintagesleds.com/library/manuals/misc/jennings/higher_compression.pdf

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TZ350

9th May 2009, 13:02

"You may be interested to know, that in many cases a non-squish combustion chamber, with its complete utilization of the mixture to offset the power-limiting effects of a necessarily-lower compression ratio, has proven to be best in absolute terms of power and economy."

Read it all here:- http://toostroke.blogspot.com/2007/12/squish-bands.html

"Our application here, of course, is strongly biased toward maximum horsepower, and that points toward a squish-band head - which is what you will have in most motorcycles in any case. I will warn you, now, that it may be unwise to follow the old-time tuner's habit of increasing an engine's compression ratio as an opening gambit in the quest for better performance. Indeed, before your work is done you may find it necessary to reduce your engine's compression ratio below the stock specification. You see, in the final analysis it is not so much compression ratio as combustion chamber pressure that determines the limit - and these are not at all the same things."

It looks like combustion chamber shape can be a trade off between broad power and maximum horsepower.

As team ESE is running basicaly identical Suzuki GP125 engines except for combustion chamber shape it will be interesting to see how this plays out over the next few dyno runs at Henderson Yamaha.

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TZ350

9th May 2009, 17:10

A cataloge search engine of all things!!!!!!

Lots of 2-stroke piston stuff. Probably can find rod-kits and other bucket stuff if you look.
http://www.who-sells-it.com/r/mahle-pistons-2-stroke.html

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TZ350

9th May 2009, 18:33

If there is any rule for the inexperienced to keep in mind. it is that everything a reasonable intelligent person should intuitively believe to be right will probably be totally wrong.

http://www.bmw-m.net/techdata/cylinder.htm

The inlet port needs only a slight convergence of 1.5 degrees included angle, which doesn't sound like much. But a 12 inch section of aluminum pipe taper-bored for a 1.5 inch inlet and a 1.498 inch outlet flows better than a parallel-wall pipe, and a lot better than air going from the cones' small end to it's beg end. Sound waves love a divergent duct, air flow does not.

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k14

9th May 2009, 19:05

The Two-Stroke Shop
Stephen Rothwell and Wayne Wright (Wobbly)

www.twostrokeshop.com
Email: info@twostrokeshop.com

THE most advanced high-performance two-stroke motorcycle engine on the market today.

http://www.twostrokeshop.com/two_stroke_shop_engines.htm

Toroidal head and flat top piston.

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In 01 RS125's converted to a head like that, supposedly it gives a better power delivery for running off unleaded. I think around 03-04 they went to flat top pistons for the a-kit ($10k+ engines) for again better power delivery for the unleaded fueled bikes. Afaik all the world gp bikes run flat top pistons and i would guess a combustion chamber of some shape like that. I was told it helps push the fuel mixture back down towards the piston before the spark plug fires.

For the leaded fuel everyone still runs dome top pistons and a standard shaped combustion chamber. Its a bit hard to know what to do though. Since world gp converted to unleaded in 97 (I think?) all the development has gone down that avenue. There are only a couple of countries that still allow leaded fuel so we just stick to the tried and true and that seems to do the trick :)

Chambers

10th May 2009, 17:50

TZ as your looking at combustion chambers and transfer patterns I found this for you. It talks about the pistons head/squish area on the left being from the old school of 50% bore dia and the one from a head made with an eye on the MSV Mean Squish Velocity produced.

From:- http://www.saltmine.org.uk/shoeman/heads.htm

"Piston on the left came from a motor using a conventional head design. It has suffered some detonation as shown by the small pieces of carbon that have been knocked off the centre of the dome. Note how the baked on stuff extends all the way to the edge of the dome in parts. The piston on the right was used with a well developed squish design head. The area of maximum heat has been confined to the centre of the dome. No carbon and oil residue approaches the sides of the dome at all, indicating no mixture is being trapped there and burning on. You can also see evidence of the flow pattern in the cylinder by reading the shading on the dome. The cooling effect of the flow from the secondary transfer ports is very easy to see in the two very light coloured small areas at the top of the piston. This is what you like to see when you remove the heads from your motor."

More from the auther can be seen here:- http://www.saltmine.org.uk/shoeman/