1999 Yz 400 ??

I just got my first four stroke, it's a 1999 YZ 400, It runs good but backfires and the header pipe glows red sometimes and the bike doesn’t want to idle , I was just wondering if this is normal? It has an fmf power bomb header with the fmf power core 4 muffler. When you’re riding the bike it seems to run good, just backfires and doesn’t want to idle and the header pipe was glowing red. Any info you can give me would be great, Thanks.

Ok, That's good to know. Thaks for the info.

backfire is a sign of running lean, try getting 1 size bigger main jet or move your needle up one

try getting 1 size bigger main jet or move your needle up one

Neither of these has anything to do with decel backfire.

backfire is a sign of running lean, try getting 1 size bigger main jet or move your needle up one

It can also be a sign of running rich...but check the easy stuff first...is the gasket at the header to midpipe joint in good shape and is the clamp tight?

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