Yz426 won't start IN GEAR

I hav a 2000 yz426 I recently bought, and i jetted it perfect I starts every time 1st or second kick, but if it's in gear I just kick and kick and kick and nothing (clutch is pulled in) hot start choke nothing it just won't start in gear, but it will bump start if I roll down a hill

And idk if this has any thing to do with it but sometimes if it's cold out and I don't let it properly warm up all the way to temp when I kick it into gear the first time it kills it but if I fire it right back up and pop it into gear it's just fine

Completely normal, my bike rarely starts in gear.

Neutral detect switch going bad?

I disabled this circuit per advice here on TT many years ago, but it was supposed to have the opposite effect by making it easier to start in neutral. There probably was some psychological effect going on too, but it actually did make the bike easier to start. That being said, I can start the bike wearing flip-flops if I really wanted (but DO NOT recommend it for safety), as long as I don't have to kick too many times. By disabling the neutral detect switch (light blue wire), it makes the bike think it is in gear ALL the time supposedly making a better spark in neutral. Not exactly what you were trying to do, but you still may have some issue with the switch.

There's too much drag in the clutch in 99% of all YZF's to get them to be very willing to start in gear. A few will, or will for a while when the clutch is fresh, but most won't.

Disabling the neutral switch helps starting in neutral, but only in a very indirect way. The neutral signal causes the CDI to lower the rev limit to 7000 RPM, and to retard the timing for a slower idle. But what ends up happening is that the timing then gets to be so late that the spark signal occurs as the energy developed by the magneto is fading instead of peaking. So the spark energy is marginally better, and on some bikes this is apparent as more reliable cold starts. There's nothing about the neutral switch that tells the CDI to deliberately decrease the spark output, as some believe, but in a back door kind of way, it sometimes works out like that.

There's too much drag in the clutch in 99% of all YZF's to get them to be very willing to start in gear. A few will, or will for a while when the clutch is fresh, but most won't.

Disabling the neutral switch helps starting in neutral, but only in a very indirect way. The neutral signal causes the CDI to lower the rev limit to 7000 RPM, and to retard the timing for a slower idle. But what ends up happening is that the timing then gets to be so late that the spark signal occurs as the energy developed by the magneto is fading instead of peaking. So the spark energy is marginally better, and on some bikes this is apparent as more reliable cold starts. There's nothing about the neutral switch that tells the CDI to deliberately decrease the spark output, as some believe, but in a back door kind of way, it sometimes works out like that.

That was a great explanation of how the neutral detect circuit functions, thanks. I just learned something today.

Edited by Pooley

BTW, disabling the neutral switch on any YZ450 will not help starting or anything else.

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