ESE's works engine tuner

[Ns1Montesa]

Josh, with additional boyesens, try to close crankcase intake port ( fully or partially, red line) , this is very easy to do with the base gasket. It was like, close the door when another opened.
Port map looks like really capable for 20hp.

I made a dyno run with duct direct to crankcase completely closed. Only Boyesens and ports in the cylinder bore open. I am suprised, engine makes exactly the same power. I will no longer spend time trying to optimise the intake. I think in my case it is not worth the time and effort. Thanks anyways Katinas!

Josh, 0,45 mm squish should make the engine more deto-resistant, but because of the squeezed base gasket the compression ratio will have risen quite a bit. Moreover, the squish geometry on many Honda engines is less than perfect, with mixture entrapment in the outer part of the squish area.

You were lucky to experience the base gasket squeezing with that Honda cylinder with its long studs. Many cylinders with short studs and ears would show their displeasure by having an ear break off. Kawasaki and KTM are notorious in this respect. If you need to raise the cylinder more than 0,2 mm, better use a metal gasket, sandwiched between the thinnest paper gaskets you can find. Or do it the quick and dirty way and apply liquid sealing. And do not overtighten the stud nuts.
Attachment 346694

What Frits said.
The closer squish will increase the com as well as increase the squish turbulence - that has the same effect as advancing the ignition by lifting the flame speed.
You can pull out some advance if running a digital ignition , or simply retard the stator some.
And yes , check that the squish band is not the many times stupid reverse taper , whereby the end gases are trapped at the outer edge , near the bore.
With the exact result you have shown , piston edge deto.

Frits and wobbly, you are right. Shape of the head is not following piston dome perfectly. I pushed the piston against the head and twisted it. You can see the "ring" on head and piston.
If my calculation is correct, comp was around 14:1. In combination with bad shape this was a bit to much, as I am using 98 octane gas from petrol station.
I have to fix the shape issue and lower the gap.

Thanks.

cheers

josh

[Frits Overmars]

Nothing to do with two-strokes, but I think you may want to see this anyway: footage from yesterday's Austrian MotoGP, the most spectacular GP, fortunately with a happy ending, that I have ever seen.

Moto2 crash
https://www.youtube.com/watch?v=muEW5EwHl08

MotoGP crash
https://www.youtube.com/watch?v=UGPrHj1nPt0

https://www.youtube.com/watch?v=q2oVM2SAIfM

[yatasaki]

When you find yourself for few weeks in city of Pesaro first what you think of are two strokes.
TMracing closed for ferragosto...
Morbidelli museum not existing any more..
Benelli museum..now we are getting started, one floor is reserved for motoBi buckets and found piovaticci 125 (air cooled head and watercooled barrel) and mba250 piston ported air cooled.

Lazzarini bmw store...offers 12 gp bikes from kreidler, iprem (looks like kreidler to me) and piovaticci 50 to125 garelli, morbidelli and mba which could tell a lot of stories at least technical..if Italians would or could talk english. A pleasant guy gave me some notes about Lazzarini bikes..on dutch
Some pictures tomorrow

[Frits Overmars]

When you find yourself for few weeks in city of Pesaro first what you think of are two strokes. TMracing closed for ferragosto... Morbidelli museum not existing any more. Benelli museum..now we are getting started, one floor is reserved for motoBi buckets and found piovaticci 125 (air cooled head and watercooled barrel) and mba250 piston ported air cooled. Lazzarini bmw store...offers 12 gp bikes from kreidler, iprem (looks like kreidler to me) and piovaticci 50 to125 garelli, morbidelli and mba which could tell a lot of stories at least technical..if Italians would or could talk english. A pleasant guy gave me some notes about Lazzarini bikes..on dutch
Some pictures tomorrow

TM racing closed for ferragosto? Make that 'Italy closed for ferragosto'; Italians are pretty resolute about summer holidays. I remember trying to get some work done in a racing department in August; I couldn't even buy an M6 bolt in Italy in August. Until I mentioned 'Reparto Corse', then suddenly anything became possible. Nice people. And they are quite willing to talk English, if only they could.
If you run in to Eugenio Lazzarini, please give him my regards. He is one of the nicest guys you can hope to meet.

[yatasaki]

Didn't mean to be annoying to no Italian in ferragosto. If Mr. Lazzarini would be present at the time I would ask him for half an hour of his time.
Very nice people and place indeed.
TM opens on monday but we're gone tomorrow. Corona is uprising again..Have missed twelve bucket races this month because of Pesaro but let's say it was worth it.

[Frits Overmars]

Didn't mean to be annoying to no Italian in ferragosto. If Mr. Lazzarini would be present at the time I would ask him for half an hour of his time. Very nice people and place indeed. TM opens on monday but we're gone tomorrow. Corona is uprising again..Have missed twelve bucket races this month because of Pesaro but let's say it was worth it.

The pictures you took at the Museo Lazzarini brought back memories. The cylinder sleeve is from Lazzarini's Maico-engined 125cc Piovaticci. Jan Thiel, who just had joined Piovaticci in 1975, had a brief look at it, after which it was one of the fastest Maico-engined bikes of its time. Funny that its 27 hp was exactly half of what Jan later extracted from the Aprilia RSA125.

Lazzarini naturally wanted to show the internals of the Garelli 125cc twin on which he was very successful. He would have been a multiple 125cc world champion on that bike, if it hadn't been for a bloke named Angel Nieto, who happened to be in the same works team and took the title six years in a row.

Lazzarini took his racing job very seriously, keeping fit during the off-seasons by doing a lot of sport, eating healthy, no smoking and no drinking. Nieto on the other hand spent his off-seasons at Ibiza, smoking and drinking all he could, while his sporting activities mainly consisted of multiple push-ups. Multiple meaning: he wasn't alone while doing 'm. Then, when the racing season started again, Nieto went on winning and Lazzarini kept collecting second places.

But I was talking about the Garelli innards in the Museo Lazzarini. The carburettors are genuine but the cylinders are not; the real deal had four additional head studs. But I can understand that Lazzarini displays a couple of lookalikes because the originals are really rare (I've got one at home ).

Below Jan and Eugenio at the Piovaticci dyno in 1975, Nieto and Lazzarini on the unbeatable Garelli 125cc twins, the internals of the Garelli twin, and the parts in the Museo Lazzarini.

[yatasaki]

There, few more to come

[jbiplane]

One interesting topic to discuss. Classical tuning pipe could be to bulky for many applications.
Rc model helicopters use different compact expansion chambers which are lightweight and compact.

I trying to make design of tuning pipe screwed to spiral. Any other ideas or experience?

[yatasaki]

Frits whats the story with van Veen and iprem kreidler?

[Frits Overmars]

Frits whats the story with van Veen and iprem kreidler?

I couldn't say. For all I know it was a Van Veen production racer, tuned and ridden by Lazzarini and sponsored by Iprem. Eugenio should be able to tell you all about it if you see a chance to meet him before you leave Pesaro.

[SwePatrick]

Long time no see
I´ve been busy building.
A friend of mine sent me a TZR250 engine from Greece.
I bought an old TZ spondon frame.

It´s built for 'moped dragracing' biggest class.
This is second startup, still a lot to adjust, is a very mild ignitioncurve in video.
But it sounds promising.

It is a Hybrid, newer 3xv jugs(ported) on an old 1kt engine.
Further on after testing it will be downsized in bore to meet up with classrestrictions(212cc)
it is 250cc now, searching for pistons, 50mm bore and 16mm wristpin, one ring, gap at 6 o´clock.
Feel free to point me in right directions if there are any

[Muciek]

Will You use ignitech to control the airjets on the carb or there will we fixed ones used?

[husaberg]

Long time no see
I´ve been busy building.
A friend of mine sent me a TZR250 engine from Greece.
I bought an old TZ spondon frame.

It´s built for 'moped dragracing' biggest class.
This is second startup, still a lot to adjust, is a very mild ignitioncurve in video.
But it sounds promising.

It is a Hybrid, newer 3xv jugs(ported) on an old 1kt engine.
Further on after testing it will be downsized in bore to meet up with classrestrictions(212cc)
it is 250cc now, searching for pistons, 50mm bore and 16mm wristpin, one ring, gap at 6 o´clock.
Feel free to point me in right directions if there are any

Nore sure re the peg but YZ100 is all of those but might have windows.
F5dave might have one left to measure.
fctory was 1 ring i think and wiesco was 2 ring

[SwePatrick]

Will You use ignitech to control the airjets on the carb or there will we fixed ones used?

There are no elecric valves at all on these carburetors, they are from rgv250 and bored out to 35.5mm(as i will run less volume in engine later on)
And i figure there aren´t need for any as i only run 201m(1/8th) and running either methanol or e85.

But i could use it if wanting to make things more refined and difficult

[F5 Dave]

I might have bits of one. Yeah factory was 1 ring. Did it have big 1/2 moon in the back? Jeez seems like a lifetime ago.

Edit. Yeah that's right. Peg was at 7 o'clock though.
Have a look on Evilbay.