I have an 07 Trx 420 that starts fine and runs 5-10 minutes then suddenly looses power and the engine dies. Sometimes it will restart fine but will die as soon as throttle is increased. Other times in restarting it will crank and backfire before starting. Plug has been replaced. Any Ideas?.......Thanks

 

Try a new fuel filter. It may not be the problem, but can't hurt, and is one of the most common causes of the "it stops when it gets hot" symptoms.

 

Thanks for your reply. Where is the filter located?

 

Let it get warm and check your spark, the ignition could be the culprit.

 

I checked the fuel filter and it's ok. If it is the ignition how do I fix it? Plug has been replaced.

 

To check the coil with out a meter, run the motor till hot and when it dies, put some gloves on pull the plug. Ground it to the engine then crank the motor see what type of spark it's got. Fat blue is what you want, orange isn't good.

With a meter set to ohms, put black lead on ground wire where the coils mounted and the red lead in the plug cap and see the resistance. Not sure the spec on that bike but my 2 yamaha are 18k or so total.

 

Thanks to all. I will give it a try.