ESE's works engine tuner

[wobbly]

OK - great, we have a proven data point for a 50cc race engine on petrol making 28.2 CHp im guessing as the dyno video didnt show it @ 16500 rpm.
Thats a bmep of 15.3 Bar , just what I would expect , especially from a couple of Dutchmen in a shed.

Now compare that to what is supposed to be the " best " 30.5cc petrol engine on the market from Quickdraw - makes 8.75 Hp CHp at 16250 = 6.9 Bar = joke.
So now I know what can be done by a Dutchman in a shed = perfectly normal technically achievable performance.
Good , lets see what a Kiwi can do with Laser Sintering , CNC cases , Ti pipes and EngMod , all from the comfort of an office chair.

[Frits Overmars]

Suzuki 50-twin continued

[Frits Overmars]

Suzuki 50-twin continued
Attachment 348001
The left-hand picture, by Kawai Mitsuo, is marked 'RK67', but in fact it shows the RK66, which had a much shorter connecting rod than its successor, the RK67.
The Kawai Mitsuo-picture also shows the third transfer port being fed through the piston, whilst the picture of my RK67 cylinder (center) shows that one year later the third transfer was directly connected to the crankcase.

[lohring]

Are there some model aircraft/boat classes where both spark ignited and glow engines compete?
The 2.5 and 6.5ccm engines have a ringless pistons and that can help produce as much power as they do
Has it ever been tried to modify a weedhacker engine with glow ignition and ringless pistons?

We did an evening of dyno runs on a 26 cc Quickdraw converted to glow ignition with a simplified WYK 33 carb. We couldn't get glow plugs to work. They either blew out the center or wouldn't light the glow fuel. The engine ran fine on the stock ignition on 15% nitro glow fuel, but burned the electrodes off the plug on 40% nitro fuel. We probably could have played with head volume and more glow plugs, but we had no incentive since we were after gasoline records.

Again, our experience with the CMB ringless piston design was poor. We weren't in the business of building complete engines; we went with the best available at the time. My friend, the late Jim Allen, claims he got 10 hp from a 26 cc Quickdraw by chroming the cylinder, running a higher compression toroidal head button, using his custom tuned pipe, and adding a custom 20 mm bore carb. I would love to see what a serious, modern 30 cc design could do.

Lohring Miller

[Niels Abildgaard]

Suzuki 50-twin continued
Attachment 348001
The left-hand picture, by Kawai Mitsuo, is marked 'RK67', but in fact it shows the RK66, which had a much shorter connecting rod than its successor, the RK67.
The Kawai Mitsuo-picture also shows the third transfer port being fed through the piston, whilst the picture of my RK67 cylinder (center) shows that one year later the third transfer was directly connected to the crankcase.

Thank You for some lovely 50ccm pornographs.Do You also have some of the final triple animal?
The picture here:

https://www.kiwibiker.co.nz/forums/a...7&d=1520911705

shows that electric transmission is worth a thought

[Frits Overmars]

Thank You for some lovely 50ccm pornographs.Do You also have some of the final triple animal?

Yes Niels, I do have pictures of the 50cc triple and a lot of other Suzuki racers, about 200 in total. But it is rather impractical for me to post them one by one.
I would gladly ZIP the whole lot but I forgot how to upload zipfiles to Kiwibiker. Anybody?

[husaberg]

Yes Niels, I do have pictures of the 50cc triple and a lot of other Suzuki racers, about 200 in total. But it is rather impractical for me to post them one by one.
I would gladly ZIP the whole lot but I forgot how to upload zipfiles to Kiwibiker. Anybody?

............

You looking for another one?

While we are waiting here is the one Hugh Anderson had here and sold to I think the Netherlands.
https://www.kiwibiker.co.nz/forums/s...post1130374843

https://www.kiwibiker.co.nz/forums/s...post1130616443

https://www.kiwibiker.co.nz/forums/a...2&d=1380532376

https://www.kiwibiker.co.nz/forums/s...post1130618964

[katinas]

So beautiful little engines, thank you Frits.
From spec chart, impressive air cooled twin RV62 250cc 42hp at 11000rpm.

Add few schemes of 1972 spec rotary valve racing outboard Veterok-70 350cc and Veterok-100 500cc (Konig copy). Interesting 350 cc power graphs with different
intake duration and different closing angle after TDC /fixed rpm. Both engines with same bottom, 54 mm stroke, just on 350cc cylinders with 45.3 mm bore.

[JdG]

Just to clear, that 50cc engine is not mine, nor did I have anything to do with it. I wish I was that good

I’m sure that Frits knows the Van Rossem brothers. Jan Thiel helped them a lot on a Dutch forum. As far as I know, this is the most powerful Dutch 50cc in pump fuel.


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[jfn2]

I have 2 questions. Why did ( not just Suzuki but a number of companies) lower the bottom of the ports below the BDC line? I know not much flow happens at BDC but it has to mess with the flow somehow. Also in the pic that Frits posted of the piston from the RK66 engine has grooves below the ring land. Were these used as a type of labyrinth seal. I notice some of the new 4-stroke pistons have the one above the ring. But I haven't seen them very often below the ring. One other question, how do I install this in a simulation program?

[wobbly]

jfn2 - Sorry to ruin your delusion buddy , but most all the flow occurs around BDC , via the large pressure delta across the Exhaust port created by correctly timed diffuser action.
At lower rpm the biggest depression occurs BBDC , it then advances thru BDC to ABDC as the fixed pipe length affects the arrival of the diffusers peak amplitude at the Exhaust port.
When the transfers first open there is more residual blowdown pressure in the cylinder , than pressure in the duct created by the piston descending - this is the sole reason for port stagger , the first transfer
to open , flows last.
The best pipes can suck the chrome off a towball for the greatest dwell time around BDC - thus the latest tuning trend is to increase the A port front wall angle right back toward the boost port
helping to reduce direct short circuiting created by very efficient diffusers.
Best example of this would be a stock TZ350 that simply refuses to make more power with a pipe bigger than 110 belly diameter.

As for having the transfer inner radius ending below BDC , maybe this was found to give a " better " flow regime when using elevator shaft ( love that term ) type ducts , as it attached the
flow to the piston early.
For sure in modern teecup ducts even small discrepancies in height, above or below , wreak the scavenging flow exit from the port.

And my guess re the groove below the ring was to lighten the piston , as it was probably derived from a die designed for two rings and had alot of unecessary skirt material between the top
of the small end and the top ring groove.

[porttiming124]

https://youtu.be/oJcnaM-hB8Q

Zundapp crankcase, std. Derbi cilinder modified. Build in a Dutch shed by 2 brothers.

Lots of hours spend though...


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Good morning all !
this forum is fantastic! thank you for sharing your expertise in 2-stroke engines!
in this video at 20 seconds for example have heard a pop?
what does that? thanks

[teriks]

Good , lets see what a Kiwi can do with Laser Sintering , CNC cases , Ti pipes and EngMod , all from the comfort of an office chair.

Im sure as h.. looking forward to follow this

[Muhr]

Yes it will be interesting to follow!

I myself spends Saturday night trying to master magic of super polish ...
And borrowed a 3d printer for carbon fiber / nylon. has managed to print the first part to the 50cc engine
Has also managed to cut some parts yesterday for manufacturing a connecting rod for the engine

[porttiming124]

Good morning all !
this forum is fantastic! thank you for sharing your expertise in 2-stroke engines!
in this video at 20 seconds for example have heard a pop?
what does that? thanks

sorry I did not copy the correct link! here is the good link to look at 20 seconds thank you


https://www.youtube.com/watch?v=6NwDSwxGpwM