Short stroke Model 50

Many moons ago I had a M50 converted to run a B50 piston giving close on 500cc. It went well enough although the balance factor was wrong so it vibrated rather badly. However, it did crack its cast iron flywheels which put an end to the experiment.

Hi John

i had this done last year by Mike p and the performance over a standard m 50 is fantastic.My bike cruises at 80 but the best part of 3 grand might put you off that is probably the only non plus point.

The spec of my bike is a 350 bottom end with a es2 head all ported and polished running his race cams and lightened rockers It has an alloy barrel with a yam piston which Mike sourced for the application

it runs a 34mm Amal concentric carb and a bth mag.i had a big problem on getting it running last year but with help from Mike and Tony Harris the problem was down to a faulty Magneto .The balance factor is right for this bike and does not cause me a problem.

My bike is in the forground with Tony Harris es4 road holder no 335 November last year on the back page.Any more info let me know

Regards

Geoff

I gather the way to maintain engine integrity if you are going to extract a heap more horsepower is to modify steel Ariel flywheels to replace the cast iron originals. A bit more expense. Iended up fitting a twin.

You should NEVER over tune or rev a single with 50/60 year old cast iron fly wheels. Having seen first hand what happends when they let go on more than one occasion, your 3K motor will be worth very little.

Just make or have made, or modify steel wheels. I always used Weslake ex speedway wheels and rod with strengthened cases in my race ES2 bike in the 80's which spent most of it's time at about 7k rpm.

Its no good tuning the top end if the bottom won't stand it.

Regards Tony