How to made a 30hp Kreidler 90cc dragrace cylinder, read below the tuning information

This is how it runs • In 3,85 sec to 100km/h...
Read here the history about the symmetric twostroke engine:
www.kiwibiker....
Ofcourse the cylinder is a very important part in tuning, but not the only one. The whole set-up has to be in the right balance, so every part has to be dedicated for exactly the same rpm range.
Read all 2stroke tuning information in my notes: www.facebook.c...
This is how I made my 30hp dragrace cylinder in 2006.
This is the only cylinder I made for the 90cc dragracer, never made a second one. I used this cylinder from 2006 - 2015
All pictures in this video are from the year 2006
The first runs were made with a 4 gears engine and 28mm carburettor. The power at the start was about 22hp at 12000rpm, which result in:
2006: 150m time 7.35 sec endspeed 115km/h
After 2006 there were made small changes and with 30mm carburettor the power was 23.9hp at 13.800rpm, result:
2007: 150m time 6.91 endspeed 119km/h
After 2010 still some little changes were made, all ports were made to the limit and with new pipe and 34mm carburettor the power ent up to about 30hp at 14.000rpm,
2011: 150m time 6.64 sec 125km/h
2015: 150m time 6.53 sec 122km/h
Engine specifications now:
Bore / stroke 53.7 / 39,7mm
UCR 14:1
Crankcase pressure ratio 1.41:1 (which is to high)
Timing 198 - 133 - 236 Rotary intake 146/82
Ignition UltraSap Curve Curve 4/1000rpm 180mJ
Power backwheel 30hp 14.000rpm
Initially I thought in 2005 it will never work well, with such a heavily oversquare engine bore 53.7 mm stroke 39.7mm. Oversquare gives less cilinderfilling, so not advisable when tuning for max power.
Also the piston was much heavier so that the crankshaft balancing would come under heavy pressure with a balance factor of 23%.
The transfers don't have a good radius, because Kreidler cylinders has no space for it.
Why made this cylinder? Because I want it simply and with the use of a Kreidler look as original as possible.
It all turned out to be particularly noticeable and drove well above expectation very soon I drove one record after another.
But also with higher power the problems became more clear, the crankcase room was to small, so the prepressure become to high with 1.41:1
This was first discovered end 2014.
I hope
In the new 100cc version for 2019 this will be corrected, incl. a stroke of 44mm, a 38mm carburettor, a new dedicated pipe and cylinderhead.
22 dec 2021 still not ready after 1 year cancer and 2 years covid problems.
Calculations
Still working on 2t program which will show very easy the engine capacity.
I stopped to made calculation for third parties (cost to much time).
I want to have more time for many special projects, not only 2t.
Searching for power might be a long way / 10200785536639832
How to make chamber and exhaustpipe / 3578245633884

[@user-vs8nt1vu5d]

Цилиндр как произведение искусства!

[@JerryLee..]

Love the innovation and determination.

[@cristianr3712]

Waiting for the 2019 Version! :D

[@schirmeyerb]

Thank you ..Luc. ... we dream......I am sure during the night ....you DREAM kreidler..

[@50ccRacing]

Sometimes ! but not every day !

[@FunAllDayLong4353]

Amazing work.

[@alfabethe1753]

Just beautiful !

[@50ccRacing]

Exhaust 198 degr Transfers 133 degr

[@50ccRacing]

@tormen with optimal transfers is about 15 procent more. Full optimised is 30 procent higher.

[@Brittvanegas]

Good work

[@user-vv-o9r]

Hello. With such a suction phase, there is a connection of the tidal channels with the suction channel. Does this help fill the cylinder better?

[@BigEsGarage]

When you say pressure became to high, do you mean primary compression pressure? Just curious. Awesome job by the way!

[@50ccRacing]

Primary compression was to high, due to the standard 50cc Kreidler engine.

[@SOVEREIGNDesigns]

♥

[@notagunfreak8146]

Beste Foekema, ik lees hieronder dat je liever niet last aan het onderblok. Wat gebruik je dan wel om bijvoorbeeld meer "vlees" te creëren? gebruik je een metaal epoxy van de winkel of mix je het zelf? En hoe borg je het epoxy dan, zet je er een pin in of? Bedankt.

[@50ccRacing]

Onder de plaat van de roterende inlaat zit een gegoten stuk aluminium met epoxy vastgezet. Ook inlaat opvullen met gegoten aluminium deed ik in 1966 ook al. De carters heb ik voor geen enkele uitvoering ooit hoeven aan te passen. Mensen denken dat zoiets direct nodig is als de spoelkanalen niet mooi aansluiten. Maar ik heb de ervaring dat zoiets eigenlijk nauwelijks iets oplevert. Voor een top racer anno nu zou ik speciaal vervaardigde carters nemen. Voor snel straat gebruik is dat totaal overbodig en kun je met standaard carters ook ruim over de 20pk halen. facebook.com/notes/1326294627709426

[@eduardbenschop8509]

When can we see the end drag results (video), and the piston+ring, and the ring closing area, how fast will it be in 400/500/600 meters? Can we also see the exhaust this cilinder will used, what about a picture of the cilhead? Can't wait to see the results, if I had that bike , original ,I would use 45 mm piston, original cilinder+ head, little bit ported (no extra ports), kitaco powerplant, 20 mm mikuni carbo.japan, and a expansion pipe for 400 meter made by myself. And then the right front and rear sproket, booom, blast fast, 23 years experience in timing, porting, pipes, ect , now I'm 49 , but still we go faster

[@50ccRacing]

You still need some time to go, I was in de front group of 5 racers (see my titelphoto at Facebook) at de TT Assen in 1968, only 4 years after I was for the first time on a circuit. So my tuning experience is more than 50 years. The end result of this cylinder you can read in de description and see in all the video's from 2006 to 2014. After that I was not ready and my health was not good enough to ride again. May be next year, but I'm sure it wil take much time to recover fully. From 2003-2018 I made about 1500 calculations for people who wanted to win races and you can read those results too in a FB note.

[@likunkmfracing8477]

Saya tertarik dengan riset anda,,apakah masih terus di lanjudkan

[@JaapGrootveld]

Beste Heer Foekema, U vermeld in uw text dat u werkt aan een 2 takt programma. Ik ben heel benieuwt of dat inmiddels tot een bevredigend resultaat gekomen is?

[@50ccRacing]

Ja heel goed zelfs. In grote lijnen is het al een tijdje gereed, maar ik werk nog steeds aan detail verbeteringen. Op FB publiceer ik daarover.

[@timoiepsma1506]

Hallo Luc Wat voorn materiaal is de bus van en waar kan je dit kopen? Timo

[@50ccRacing]

Is gewoon 51st maar 28st is nog beter om te nicasylen. Te koop bij Elcas Rotterdam.

[@ezequielartigas454]

What is the diagram of cylinder? Transfer , exhaust port boost ports?

[@50ccRacing]

Exhaust 198degr Transfers 133 degr.

[@Alwaysbusy300]

Ooo

[@zeca8864]

Hello Mr Foekema, i believe you will use rotary inlet. How much degrees will the rotary valve have? Thank you

[@50ccRacing]

The duration of the rotary valve is 230 degr.

[@AbdulHadi-hs1uf]

does the engine got power valve ?

[@50ccRacing]

No I don't like powervalves on twostrokes. A racing engine never needs one, because you never run in the rpm In which it should work. Only at the start 1 second.

[@Patricks_Projects]

Ever been dynoed or just simulated? If dynoed, crankpower, sprocket power?, having hard time beleiving it should be rear wheel hp.

[@50ccRacing]

On track, on dyno and calculated !

[@Patricks_Projects]

@@50ccRacingcrank, sprocket or wheel?

[@gg-yp1ow]

Do you welded the engine block with mig?

[@50ccRacing]

No never welding on engineblok, it create many problems.

[@gg-yp1ow]

@@50ccRacing what did you instead of welding? Since your cilinder won't fit on the original casing.

[@50ccRacing]

@@gg-yp1ow use liguid metal/epoxy to fit extra material and sqrew it to keep it fit.

[@jurgenrunge1745]

@@50ccRacing is there no problem of something like a heat barrier when using epoxy to glue the race?

[@jurgenrunge1745]

@@50ccRacing what clearance do you use to fit the new race into the cylinder. Very tight (maybe 0,02mm) or more likely about 0,05mm to give the epoxy some space?

[@cristhian89movil9]

What is the length of the connecting rod? What ratio of precompression use in the crankcase

[@50ccRacing]

Conrod lenght 85mm. Crankcase CR 1.41. But this should be lower.

[@cristhian89movil9]

How many degree open exhaust aids and when do they close?

[@50ccRacing]

Open 81degr ATDC and close 81degr BTDC

[@cristhian89movil9]

What did Rc use? And could you tell what ignition curve it uses? How many degrees of progress and how much is your maximum RPM

[@cristhian89movil9]

Can I also use the previous low compression on a reed valve motor?

[@NiekSchramaofficial]

Hoeveel spoelpoorten zitten er in?

[@50ccRacing]

Van 7 aan de voet naar 5 aan de cilinderwand.