xr80 shut down

[wornknobby]

my xr80 still only runs for like 5 min and then just dies. everything is cleand(carb,aircleaner,oil, etc..) when the bike is running though it runs great. i did find that the ignition cover broke a piece of aluminum right in front of the srpoket and dirt and some metal got all in the flywheel. i cleaned it all out and JB welded the little arm that comes off from the stator plate and holds some kind of senser that trips with some oter senser on the flywheel because there is a little rectangle of metal on the flywheel. i put a new cdi box in it. when i pull the plug the very tip is somewhat white and the inside with the electrode is still black. can any one help i can't think of anything else to do!!!!!!

 

[03YZ85Rider]

I used to have a '78 XR75 and I had the same problem you are having. It turned out the ignition coil was bad. When it started to get hot it would start bogging and die and wouldn't start until it cooled off. After pushing the bike all the way home it would fire up on the first kick! Check or have or coil checked with an ohmeter, check the specs in the manual for resistances. Hope this helps

 

[Jasle]

when the bike quits running then have a spare plug handy. pop it in the plug wire and hold it to the head while kicking and look for spark. Then you can eliminate 1/2 of the equation. find out if its a spark problem or fuel problem. also testing the coil while its cold won't hlep. if you do ohm it out do so after the bike has warmed up and quit running.

Personally I'd pull/clean the fuell petcock and make sure my float level was adjusted properly as I think this problem is much more likely to be fuel related but ignition problems do happen just not as likely.