Well, I did the cam mod, apparently incorrectly. I went rididng today for the first time, not including riding up and down the street. I was running fine for about 10-15 minutes and then in 3rd gear my engine just froze. It was like my battery was dead. so after getting towed back, i starting looking at my engine. after taking the plug out, I could not even budge the engine by cranking it manually. SO I pulled everyting back apart in the parking lot. Probably not a good idea since it's dusty. I could not even budge the chain on the motor. To make matters worse, I broke the adjusting bolt on the chain tensioner. The crankshafts did not look like they were anywhere near top dead center. I put it all back together, but now there sounds like a loud screeching coming from my engine??? So, unfortunatley my day was over. Loaded back up and came home. I will tear motor down tomorrow. Any ideas or suggestions on what has gone wrong???

 

Sorry to hear that? It almost sounds like it jumped timing but then you will find out more once you tear it down.

 

sure sounds like you jumped timing to me, too. the screeching sounds like it could be bearings. if it's a steady screeching that gets faster with the acceleration of the motor, it's probably your rod bearings. im not sure how the 450's are built, but check on the camshaft where the timing gear sits. there sould be a woodruff key or a pin that sticks out of the cam shaft. my buddy has a warrior with an aftermarket cam in it, and it sheared that pin off and jumped timing and blew his top end pretty good. it looks like someone took an extra valve and dropped it in the top end a let it jam around in there for a couple hours. hopefully its not that bad, but you never know. good luck.

 

Thanx for the info.

 

I have been reading quiet a few post on here about people having problems with the YFZ450 engine... When you do find out what happen let us know....

 

this is probably a dumb question but it doesnt hurt to ask....i dont know about cam but was there enough oil.was your oil level full..[img]i/expressions/face-icon-small-disgusted.gif[/img]

 

Well,

I re tore the engine down and redid the cam mod. it looks like the cahin was skipping over the cam. I also think I tightened the top down way too hard. I know it was a lot more than 7.2lbs. Anyway, I got everything back together and now the bike won't start. The engine is cranking, but will not turn over. I put a brand new spark plug in and got the same result. So I tried to pop start it and it started to run except for when I pulled the clutch in, it died. I am at a loss. What would cause this????

 

It sounds like the timing is off, way off.

 

*NODS HEAD IN BELIEF*

 

I may be wrong in this, but doesn't the flywheel have two sets of marks on it? Would this problem happen if I set top dead center to the wrong set of marks??