ESE's works engine tuner

[Yow Ling]

I have seen in a quite a few right ups from seemingly reputable sources that chains primaries are more efficient.

Now don't get me wrong, i come from a history of British shiter's with chain drives so i am definitely not a fan.
But in the early classic movement the chains were replaced by Belt primary's for a reputed gain of 1.5hp to 2 HP per 50HP and no oil on wheels etc longer life etc quieter ...

So if this is the case why aren't Real COMPETITION bikes running around with Belt drive primaries. As if it were true there would be an easy few HP there?

Modern bikes use mass centralisation , stacked gearboxes etc to deliver a compact engine, using a belt primary necissitates a big gap between engine output shaft and gearbox input shaft to allow the belt to wrap around the small belt sprocket, this allows more teefs to carry the load

[husaberg]

Modern bikes use mass centralisation , stacked gearboxes etc to deliver a compact engine, using a belt primary necissitates a big gap between engine output shaft and gearbox input shaft to allow the belt to wrap around the small belt sprocket, this allows more teefs to carry the load

Too true but the packaging issues are going to be limited by the size of the crankshaft anyway but i do see your point.
Pre-unit construction engines and the bits unit ones as well obviously had lots of room

Actually was the Swissauto Geardrive or Belt drive WOB?Hindsight (and attachment viewing) i think it was the Yank V4 I think the swissauto had only a water pump belt drive like a f3 car.

[dinamik2t]

Ohh look page 500. 3rd bump then I give up

Dave, I have no experience on the matter, but I have a few notes on some pistons/wrist pins, which include the inner distance of piston sides (wrist pin area) and the wrist pin width. I avoided giving you those number, since it's no real reference nor racing specs (not necessarily).
It's not much, but it might help as examples of what a manufacturer would use - which, in most cases, is safe at least. I 'll have them tonight when I get back home. If I forget, do send me a reminder PM!

[Grumph]

Husqvarna of all people did a 50cc moped power unit which used a belt primary - which looks to be about 30mm wide.

A belt primary set for a British single is actually dearer than making up a primary gear set...but it does include the clutch too.

[bucketracer]

Wish youse guys would post a curve with 0rpm as datum to give a sense of perspective

There you go ......

[husaberg]

There you go ......

Oh that clears that up nicely

[dinamik2t]

There you go ......

That's double the power of TeeZee!

[bucketracer]

I have shown several dyno runs with similar peak power, just thousands of rpm less, and over a far wider "band"

Similar power, wider power band, but were they a similar engine to TeeZee's high 20's to 30+ hp 125cc rotary valve air cooled engines running a 24mm carb. Could you post something because I can't find it.

i can't claim responsibility for this engine, but (so far) the highest power i have seen from this capacity with a 24mm carb is this series of runs.

I looked through all your posted dyno graphs, and this is the only one where the text refers to anything that's similar to TeeZees engines.

And that graph was posted less than 3 years ago.

125cc (123.67cc to be exact) Vespas have been putting out more than 28PS for at least 5 years.

OK, I am confused, ....... please help us out here.

[F5 Dave]

Dave, I have no experience on the matter, but I have a few notes on some pistons/wrist pins, which include the inner distance of piston sides (wrist pin area) and the wrist pin width. I avoided giving you those number, since it's no real reference nor racing specs (not necessarily).
It's not much, but it might help as examples of what a manufacturer would use - which, in most cases, is safe at least. I 'll have them tonight when I get back home. If I forget, do send me a reminder PM!

Thanks, it would give me some measurement of what is possible to run.

[SS90]

Similar power, but were they a similar engine to TeeZee's high 20's to 30+ hp 125cc rotary valve air cooled engines running a 24mm carb.





I looked through all your posted dyno graphs, and this is the only one where the text refers to anything that's similar to TeeZees engines.

And that graph was posted less than 3 years ago.


OK, I am confused, ....... please help us out here.

It is 2012.......

Anyway, here is a blank liner 55mm, simple to make, its possibly time your Father made one. I believe GP125 cylinders are "cast in", so it will take a bit of machining.

Perhaps even a new Skin is in order? you can make one from solid stock if need be.

I have used 54mm 55mm and 56mm pistons making my cylinders (small end sizes are a pain in the arse for these rods), as sometimes you have to use what pistons are available.

The best cylinder you can buy uses a 54mm Vortex Piston, high quality 56mm pistons are available for a full retail of the eqivilent of $NZ100, which ends up slighly over 125cc, and the Vertex are at least double that.

28PS, 54mm bore, yea..... that came out about 5 years ago. And you can bet there was a few clever guys doing their own stuff before that.

[SS90]

Not sure where you got that from, maybe a quote or two would be handy.



There is no doubt about how impressivly Av cleaned up at Tokoroa and then again at Te Puke on her RS/GP125. The bike was prepaired by Chambers and based on TeeZee's work, the engine layout followed TeeZee's ideas posted earler.

I don't think anyone doubts that more hp in her hands will be devistating.

Erm, your second quote maybe?

More power? I cant see how that is needed, given that from what I can ascertain, the winning bikes have just over 22 HP or so, and they are all making that power below 11,000 RPM (is there anyone with a power graph of the winning bikes?)

a 125 2 stroke can easily make that type of power, it is done every day.

[SS90]

125 Aircooled with 24mm carb - bucket rules, is the challenge.
I will gladly suck the chrome off anyones towball that can do anywhere near 30 Hp at 10500 - im bloody good at this shit and wouldnt even try - doomed to failure.
That requires around 35 crank Hp, and equals 11.9Bar 0r 175psi BMEP at 10,500 - dreaming , as at that level you are screwing the tuning down real tight and the
perceived advantage of any power-band width has just gone west.
Mr Physics wins again and I keep my dignity.

Im not saying that 30hp at 10,500 is required there Wobbly.

What is possible is say 22-25 HP at 10,500, and that, from my experience is not only feasable, but race winning as well.

Speedpro, from his recent posts in his thread is the most likely person to achieve this. If he runs his planned 192 degrees, and with the time area limitations of his single exhaust port, he will be limited to achieving power with a lower rpm ceiling, and with a pipe deigned accrdingly, he is going to have a grunter.

its nice to see 30 hp buckets, but it seems far less than that is required to win races.

Mind you, if someone was to get hold of a Cagiva Mito (7 speed model), sleeve that down to 100cc, and use the port map you used on Speedpros cylinder, along with that exhaust, you would in all likelyhood have the fastest bucket on the planet (as the fastest bucket in New Zealand is currently a 4 stroke 150, as races are won on lap times, not back straight speed)
I have often wondered why no one has really gone into expansion chambers in a big way on this thread.....

[Haufen]

"heaven on earth" how so?

Last time I checked (this afternoon) small frames are all 4 speed, and other than some short fourth manufacturers, you are limited to either an ET3, PK80 SS50 or Primavera übersetzung... Although the 50s had a "long fourth", and works well with certain set ups.

That's strange. There are dozens of other options. I don't want to get too offtopic here, so I will list a couple of gearing possibilities that come to my mind right now, and if you want to know more just contact me via PM.

Primary Ratios:
the ratios you mention are: 2,54 (ET3+Primavera), 2,86 (PK80) and probably 3,72 (SS90). Apart from these you can also get, for example, 2,34 (68/29), 2,56 (69/27), 3,00 (72/24). For all these straight cut primary gears there are aftermarket pinions available, usually one or two teeth apart from the standard pinion so you can make very small adjustments.

for 2,34 (68/29) there are pinions with 30, 28, 27 and 26 teeth giving a ratio of 2,26 / 2,43 / 2,52 / 2,62
for 2,56 (69/27) there are pinions available with 28, 26, 25 and 24 teeth, resulting in ratios of 2,46 / 2,65 / 2,76 / 2,88
for 3,00 (72/24) there are pinions available with 25, 23, 22 and 21 teeth, resulting in ratios of 2,88 / 3,15 / 3,30 / 3,45

and I am sure I still may have missed some combinations.

As far as the gears are concerned, amongst others, there is at least one five speed gearbox that is able to cope with serious horsepower. But as that is not a mass production thing and thus pretty expensive, let's concentrate on the traditional 4-speed gearbox.

Most commonly used is the following:
1. gear 58/10
2. gear 54/14
3. gear 50/18
4. gear 46/22

using aftermarket gears and christmas trees you have the following chioces (at least, I am not so sure if I am up to date on this)

1. gear 58/10, gears available with 56 / 55 / 54 teeth
2. gear 54/14 gears available with 56 / 55 / 52 teeth, christmas tree availabe with 13 teeth also
3. gear 50/18 gears available with 51 and 49 teeth, christmas tree available with 17 teeth (all can be combined), also 16 teeth tree available (don't know about compatibility)
4. gear 46/22, gears available 48 teeth, christmas trees available with 21(46), 21(47+49), 20(47), 19 (47), 18 (47), 20(46)

And there is even more. Heaven on earth, isn't it?

In F4 a 100cc 2-Stroke can be water cooled and have any size carb, a 125 must be air cooled and is restricted to a 24mm carb.

TeeZee has managed to make 31 hp with his old 125cc air cooled engine from the 70's and with some development I expect he will get it reliable too.

Casting your own cylinder is allowed and a pretty impressive thing to do. RGV250 cylinders have been sleeved down to 100. And TeeZee has looked at air cooling one too. RG400 cylinders are/were also popular.

Basically anything you make or can modify from a non-compitition engine is allowed.

I think you can be very happy with your regulations, as it looks like they allow for a great amount of freedom of choice without any setups / directions being superior to the rest. Too bad I am living on the other side of the planet, if I were in NZ, I'd surely take part. Are there any european 125cc two-stroke street bikes available in NZ, for example Aprilia RS125, or Cagiva Mito (Evo)?

And, by the way, this thread is a great read! I really like the attitude of sharing experience and helping each other which is present here

[SS90]

That's strange. There are dozens of other options. I don't want to get too offtopic here, so I will list a couple of gearing possibilities that come to my mind right now, and if you want to know more just contact me via PM.

Primary Ratios:

and I am sure I still may have missed some combinations.

As far as the gears are concerned, amongst others, there is at least one five speed gearbox that is able to cope with serious horsepower. But as that is not a mass production thing and thus pretty expensive, let's concentrate on the traditional 4-speed gearbox.

Most commonly used is the following:
1. gear 58/10
2. gear 54/14
3. gear 50/18
4. gear 46/22

using aftermarket gears and christmas trees you have the following chioces (at least, I am not so sure if I am up to date on this)

1. gear 58/10, gears available with 56 / 55 / 54 teeth
2. gear 54/14 gears available with 56 / 55 / 52 teeth, christmas tree availabe with 13 teeth also
3. gear 50/18 gears available with 51 and 49 teeth, christmas tree available with 17 teeth (all can be combined), also 16 teeth tree available (don't know about compatibility)
4. gear 46/22, gears available 48 teeth, christmas trees available with 21(46), 21(47+49), 20(47), 19 (47), 18 (47), 20(46)

And there is even more. Heaven on earth, isn't it?

None of these are new (DRT was making crank gear "conversions" many years ago), the bottom line is that no matter which way you shuffle the cards, there are only 4 gears to play with (making layshafts is an expensive process, by any ones standards, although I have recently seen cheaper ones on offer)
5 speed conversions? I am yet to see one that can last the distance. The restriction of gear ratios is a constant thorn in your side, but it does force you to create engines with wide power spreads, which is always nice.

[Yow Ling]

I have often wondered why no one has really gone into expansion chambers in a big way on this thread.....

They have you just wernt looking. In fact your first rants were about how Thomases cousin stole the worlds best pipe design from your mate the pipe genius and that was why all asians could not be trusted ever again