Thanks, good to know that it can be done. I was starting to look for a replacement crankcase!
Alan

The thread in my engine casing that holds the swinging arm spindle has stripped. What's the remedy for this? The threaded hole is rather inaccessible.
Thanks
Alan

Finally stripped the gearbox down today to try and find out where 4th gear had gone. Seems to be a selector problem, see photo. The engaging surface of the fork has about 0.010” wear DDA7D436-5945-44DB-95E2-03E7BF471F28.jpeg
This didn’t seem enough to prevent 4th engaging, so I looked further. The ...

Yes, well spotted, it's the same bike. I started off with a siamesed system,using 2 arrow front pipes, and the 4 stroke exhaust from the Bullet. I also have a Yamaha TDR 250(what a bike!) and this came to me with a spare exhaust system. I wanted an expansion chamber and decided to use the TDR pipes ...

Maybe this crankcase was fitted with alloy barrels at one time. These have bigger transfer ports. Looks like fitting reed valve kit increases crankcase volume quite a bit, so it could be to reduce crankcase volume.
I fancy a feed valve conversion for mine, it does give you far more flexibility with ...

Having built up my 250 engine, originally planned for fitting into a Bantam frame, I was concerned about the brakes and suspension on the Bantam, having had a few, and decided instead to fit the engine into my Royal Enfield Bullet. This has a 7 inch TLS brake and well sorted suspension front and ...

Yes, that’s the one! Thanks Alan

Having assembled and run my 250 arrow engine, with new exhaust pipes and sealing rings, I cannot achieve a gas tight seal. One of the barrels has adifferent thread depth for the threaded collar,approx 5mm different to the other side. I suspect that the collar is bottoming out on the thread rather ...

Keith, thanks for your help! I turned the whole plate through 180 degrees and bingo, points operating correctly and with plenty of adjustment. The eccentric cam makes setting the timing really easy.
So that was the answer, thanks to all who have suggested solutions. This is an excellent
Forum, I ...