mattyholmes100

If your measurements are in mm and your first number is diameter then i get it as 430cc. Don't quote me on it as its a long time since i was at school!

Motors TV have been showing indoor trials lately. Sky channel 413,

You should be able to get a resistance reading through the fan motor. If you have put the fan in a circuit with a battery and it still doesnt run then sounds like its had it.

Royal Enfield used to do a diesel motorbike. Maybe they used to trial them???

I find Birketts great to deal with. Not had any dealings with warranty issues but find them very helpful with technical advice and parts supply. Will talk you through a repair rather than sell you a new part.

I use putoline boot wax. Seems pretty good.