My 2003 Grizzly began to back fire, then stall. I brought it back to the dealer, and they changed athe rev limiter pin under warranty. The next ride I had, this time the bike would just die out. I would be riding, with my thumb on the throttle, and the bike would just lose all power and come to a complete stop. When I tried to re-start, the bike would not start. I had to wait about 5-10 min to restart. This happened all day. I already had the modifications done to stop the vapor lock and gas boiling, but why is this still happening> I'm still waiting for the Yamaha district service manager to get back to my dealership. The dealership doesn't know why this is happening....Does someone have any clue?

 

is a winch installed on it? this is a stupid question but sometimes if the person isnt familiar witrh it they can pinch hose around the frame when tying off the winch cable to and from the soleniod.

It may not be the problem, but worth a check. The mechanic may have thought of this already and checked it.

 

The vapor-lock mods might not be working. Did you check your tank for boiling fuel?

 

I would make the only sense. I'm not sur if the gas is boiling. I'll have to check for that. Thanks

 

The gas does not have to boil to cause vapor lock. If the gas in the tank heats to the point of expansion the gas will have to cool and contract, and, at some point cause vapor lock. If the Grizz cuts out again unscrew the gas cap to see if you can hear suction release from the tank. Then try to restart the engine.
This sounds like it could be the cause of the problem you described to us.

 

well this is one of those stupid but easy questions! Did you ever try your vent tube coming off your gas cap?? Gets plugged!! Mine will do this! Kills the engine!

 

Yea one dude we were riding with on a Grizzlys bike backfired then stalled. Some guy came and took his gas cap off and tried to start it it fireright up and he rode for the rest of the day.

 

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I VERIFIED THE GAS CAP, AND CHECKED THE HOSE. THE HOSE WAS FINE BUT THERE WAS SOME DIRT INSIDE OF THE CAP, UNDER THE METAL PLATE (I REMOVED THE 3 SCREWS ). tHE BALL BARING WAS ALSO DIRTY, SO I CLEANED IT TOO. I DON'T RECALL HEARING ANY SUCTION NOISE FROM THE GAS TANK. I DID TAKE OFF THE CAP TO SEE IF THE GAS WAS BOILING.
IF ANYONE HAS ANY OTHER SUGGESTIONS, PLEASE SEND THEM.

 

I would say that you probably fixed the problem. Have you taken it for a ride after this fix? Is it still doing it?