My brother's '03 trailboss 330 is blowing it's sparkplug out when he rides it. Looked at the plug and the threads look chewed up. The threads on the plug hole also look chewed up. I'm guess it came loose and wallered out the plug hole before it finally blew out. Can this be fixed or is the atv just screwed?

 

worst case you'll have to but a new head for it. i have a plug thread chaser to fix bad threads. so it might be fixable but if it's blowing the plug out of the whole chances are its really screwed up and wore completely out. ( note, if you do try to fix the threads buy chasing them or what ever the filing are goign to go down in the ebgine. not good. i would just take the head off and then decide.

 

Try putting in a new plug........if it still does that, I'd probably say you might need a new head, or some real machining

 

Thanks guys. You wouldn't happen to know a good place online to find one would you? The local Polaris dealer really sucks. Again, thanks for the help.

 

Try a heli-coil or thread-sert. Both will repair stripped threads. you can do it yourself if you are careful. Kits are about $30.00 and you wont have to take the head off. After tapping the threads use compressed air to blow out the shavings or crank it over with out the plug in it. I have used then on aluminum corvair cylinder heads. Should find them at main auto, napa etc.

Steve

 

Whether you tap the head or use a heli-coil, pack the taps with wheel bearing grease. That will hold the metal shavings from dropping into the cylinder. I have used heli-coils on Ford 5.4 and 4.6 with aluminum heads with great success. (Ford doesn't recommend a heli-coil but its cheaper then a cyl head and re and re at 12 hours @ $90)