I bought a project 2002 300ex that would not run. My first suspicion was that it wasn't timed right so when I went to time it I noticed I could turn the flywheel but the cam wouldn't turn with it. The cam does rotate very freely on it's own tho. There's not much slack in the cam chain so I don't think it slipped off the lower gear. Possibly the gear is stripped completely or is there something else that could cause this? Thanks for all the help!

What all is involved in changing the lower gear if that is in fact the problem? Is that lower gear part of the crankshaft?

 

You will have to heat that gear up an remove it then heat new one an slide it back on crank an let cool off!! Just make sure TDC...

 

Usually you just have to pry the little key out and possibly there will be a reverse threaded nut holding the gear in place. With the $$ you will save by doing this yourself, it is a good idea to grab a shop manual for it!

 

The root of the problem wasn't as bad as I expected. The timing chain slipped off the sprocket. I put it back on and the cylinder, piston and valves all looked good so I fired her up and she runs great.

 

Great.........................Ride Safe...Enjoy..

 

That's great but I'd be concerned about what caused it to slip off the gear in the first place. If that problem is not adressed, it will more than likely happen again.

 

Right I agree. The new timing chain should be here in a few days. The old chain is just too stretched out.

I got this for my girlfriend. Hopefully I'll be able to ween her off her beloved 250ex.