I took my 06 yfz450 for a short little daily ride the other day down a trail by my house, it wasent even 15 minutes of riding then headed back to the house down the road in 4th gear and it shut off. Hit the start button and all it did was click. I let it sit a minute and tryed it again..it clicked,clicked,then started to turn as in if the battery was really low with a sluggish sound then caught and fired up. It ran for about a minute then cut back off. I can hit the start over and over and it just clicks, but once in a blue moon it will fire up and run fine for about 20 seconds then will just shut off. I took the little gear/flywheel lookin deal off thats by the starter and hit the start and the starter spins strong everytime. It does have a pro armor kill switch, and when i pull that cable thats suppose to kill it, the starter will still spin when i have that flywheel/gear off.I'm not sure if its supposed to do that or not. This atv has been flawless since i have owned it. Its driving me crazy that it might be something simple, i cant stand not riding it. The battery is fully charged also. Any help will be a great help! Thanks again!

 

Did you run out of gas?

 

Nope its full of gas. Even if it was empty it would still turn over just not fire up and run. The starter wont turn the motor over.

 

Am i looking at a coil problem? What would make it cut off and then not turn over? it'll start up and run strong for about 15 seconds then cut off.

 

Your lower crank bearing could be siezing up, I have seen a few do this.

 

I called the local Yamaha shop, they said its probly not the crank bearings because when it does run that the motor runs smooth and quite.

 

Sounds like a wiring problem to me. A loose wire or bad ground or bad wire to the starter etc....

 

OK, then try this one more step. Remove the plug from the bottom of the fuel bowl, drain it then turn on your fuel and see if a lot of fuel comes out at one time. I had one where the needle was stuck in the seat area and allowing very little fuel in the carb.

Oh and to let you know all the other 450 engines with bad lower crank bearing ran and idled fine as well till they blow up.

 

yeah i'm starting to think its somethin that came loose..i've been looking and havent found it yet.