I did the cam mod on my '04 YFZ 450. I followed detailed instructions the whole way through and now my bike doesn't want to ideal and it wont start without giving it throttle while cranking. It used to start very easy.

However i haven't rejetted it yet. Could this be part of the problem or is there something more going on?

 

It is common to go up 1 size on the pilot with the cam mod. If you were lean before doing it, I could see those symptoms coming up. The other thing is, are you positive you retarded the exhaust cam instead of advancing it?

 

yes i retarded it. there are 13 teeth between the marks now instead of 14. I got it to where it will ideal a little better but if its gonna run like crap now i would rather put it back to stock

 

Something else is wrong then. The mod can make for a bit harder starting but nothing dramatic. I actually have one right now with the cam mod and running high comp. that starts at the first touch of the starter button.

 

ha i actually fixed it today. i took it apart agian to see what was going on and i discovered that i had it retarded right but i managed to knock the timing off of TDC so the cams weren't timed right. But i got it all taken care of and it fired right up.

Thanks for your advice though!