XR650 l starting trouble ?

[Bobby Blumps]

My 02' 650l occasionally has trouble re-starting after about a 40min ride. Here's what's done to it so you know what was messed with. Removed smog pump & snorkel. UNI filter. Dave's carb mod with 55/160 jets (sea level). FMF power bomb header & powercore 4 muffler. Some have said my main is to rich but the bike runs great all through it's range. It's only once in a while after a little ride that it doesn't want to start. Every time this has happened it's when I've tried to start it shortly after shutting it down (about 10mins). The ol pig only has 7800 miles and I'm not sure what this problem could be. Last night after one of these 30min rides I stopped in the store and it took about 5mins to start. After it starts it once agains runs great. Any experience or ideas would be appreciated, thanks. 

[ScottRNelson]

The short answer is for you to shut off the fuel about half a block before you shut the bike off if you know you'll be restarting it sometime within the next half hour or so.  That seems to work for these bikes.

Your main jet should have nothing at all to do with starting the thing.  Still, a 158 or even a 155 is likely to work better with your modifications.

I'm not sure anybody knows for sure, but it is the theory that when you shut off a hot XR650L, some of the fuel in the carburetor evaporates into the intake, or something, and makes it too rich when you try to restart it later.  Shutting off the fuel a little before shutting off the bike uses up some of the excess fuel, making it easier to restart.  I'll usually flip the fuel back on about three seconds before hitting the starter button and my hot starts work just fine.

If you can't get it to start in the first 30 seconds when hot, flip the run/off switch to off, hold the throttle wide open, and crank it for a little bit.  Then turn it back to run and try starting it with the throttle closed.  I don't have much experience doing it this way because I don't usually have the need when I shut the fuel off before the engine.

I would be interested to hear other ideas about this.

[brianhare]

Mine did that the first year I had it,,,,,,,,and is also why I wrote the CDI repair thread,it would run great till I shut it off,then took awhile to start after,,about 10 minutes or so...resoldering the CDI fixed that issue...

 

but it became an issue 4 years later again.....if I shut it off hot on a trail,,i was stranded for awhile,that time it was the pulse generator....another known  no-spark failure point..

 

you need to check for spark when it won`t start,bring a spak plug with you,,and when it doesn`t start,,pull the plug wire,insert your spare plug,,ground it to the head and see if it fires ...

 

B

[ScottRNelson]

Brian, that reminds me of how it went with my bike.  Until I replaced both the CDI and the Pulse Generator, hard starting when warm was a frequent issue.  Now that I have a solid CDI in there and a new Pulse Generator, I haven't had much of a problem getting the thing to start.  I may have to do some experiments with that, shutting off a hot bike without switching off the fuel and see how it starts 20 minutes later.

[Bobby Blumps]

Thanks guys. Gonna start shutting the fuel off before I stop and see if the problem continues or not.