The timing is ok. Marks line up. However the crankshaft will only turn 3/4 of a revolution. Surely it should rotate indefinitely? Something is locked up

Turn it with the cam covers off and see if there is suddenly a large valve gap, I am guessing there is a bent valve which is not closing and is stopping the piston

thanks tiger! good idea that, ill measure valve clearances.

in 0.12-0.18 (0.005-0.007)
Ex 0.17-0.23 (0.007-0.009)


according to manual, ill check em

After talking to garage and a great deal of head scratching. They reckon it's either dropped a valve or the con rod. Either way the engine will have to be opened. How tricky is it to remove the head? Does whole engine have to be taken off bike? . Owners manual says it does

I think the engine does have to come out its a heavy little bugger too.
You will need help but you can do it on your own if you have access to a pulley lift and some sort of gantry/rafter that can support the weight of pulley and engine weight.
I removed mine and replaced it on my own with this method the engine I supported with rope around the base of the barrels to get it out it needs to be fairly level as it sits in the frame there is just room to lift it and swivel it to ease it out.
Take your time and dont try to rush it .
Where are you perhaps there is someone close by that may be able to help.

thanks superjack, ill take my time, sounds dam tricky though


I live in Heswall on the Wirral

dave