I have a 2004 YFZ450. It starts, idles and goes great when cold. After some time riding it and it get hot it starts to pop and sputter at high rpms. Also battery dies when it gets hot. Recharge battery and let it cool down and it starts and runs great again until it gets hot.

 

If the battery is kept charged when hot, does that help?

 

By the time it hets charged the bike cools down.

 

how about jumping it from another battery temporarily? Electronics hate heat, so anything that might be touching the engine could be cutting out, something like a regulator.

 

Will try that. Thx

 

If the battery is going flat, sort out the charging circuit. Either there is a very heavy drain on the battery or it isn't charging. Test by starting the bike up and putting a voltmeter across the battery. It should rise with revs and stay there or fall away, but should always be more than when the bike isn't running. The max is 14.5v. To check for a drain, disconnect one terminal and, with ignition OFF, connect an ammeter between battery post and lead, any more than 0.01 amps is too much. This doesn't check for drains in the wiring circuit beyond the ignition switch, but a heavy drain would blow the main fuse.

 

Had that same issue on a warrior once and it was the stator.