05-27-2002, 05:31 PM
Ive just recieved an EX to work on. The problem is, it was just rebuilt with a 420cc big bore and jet kit. It will not run, it will backfire and afterfire. I checked the valve lash, fuel and for spark. I did a leakdown test 10%. The only thing that checks out bad is the timing. The -T in relation to the camshaft is a half tooth off. Ive tried retiming it and its still off. I went by the Factory Manual and still off. The cam chain tensionor is working fine. Has anybody had a stretched chain? And if so would 2 to 3 degrees keep it from running? I know its going to advance it or retard it hair, but Im not familar with the personality of this engine. Thanx!