Motor won't start after it's at running temp

[5pennys]

Hi guys, I've had this issue with this motor for the entire time I've had it.

The quad will fire up quickly and easily when the motor is cold/cool, but as soon as I get it up to operating temps it doesn't want to start again.

Example: I start it up, let it idle for a little bit, and then begin riding. If the motor dies any time after that, I have a hell of a time getting it to start again with the electric start (most of the time I have to either get pulled or pushed to bump start it, but it fires up really easily when I do this). If I let it sit and cool off for a while, then it will fire right up again using the electric start.:confused:

To add to the confusion (at least for me), the motor runs very strong with no issues while its running. It idles well, and throttle response is very crisp with no hesitation anywhere in the rpm range. It just doesn't want to start up once it's hot.

Here's the info that I know of on the motor given to me by the previous owner:
2005 YFZ450- Ported head, web decompression cams, cp 13:1 piston, WR crank.

I've talked to a couple of local riders and the only information I got was that the valves might be adjusted to tight, and that that can make it hard to start once the motor is hot.

Any help is much appreciated. Sorry for the long post.

[Ride1Rob]

Valves could be tite and that could cause the bike to do that. Check to make sure their in spec 1st and if they are it's more than likely your bearings. Either rod or crank.

[sand45]

sound like the valves to me too....check to see if you have them to spec's.

[5pennys]

Thanks for the help guys. I will check them as soon as I get a chance, and make another post in this thread with anything I find out.

[Sweendogie]

is the cam mod done? if it is put it back to stock timing i had the exact same problem and when i put it back it ran flawlessly and started flawlessly every time

[5pennys]

Sweendogie- I don't know if the cam mod has been done or not on this motor. The previous owner didn't say anything about it being done or not when he gave me the description of what all was done to the motor.

I'll check it out though when I take a look at the valves.

Thanks

[mbx5]

Might seem odd, but check your neutral switch!! Mine did the same thing to me - would start cold, but if stalled I had to be pull started again - ended up being a bad neutral switch...took forever for me to figure out - I thought it was carb related, etc.....