NC30 misfiring when hot

[Neosophist]

Random idea - but try and run it with the airbox off and spray a little fuel into the cylinder (plastic spray bottle or similar), see if the cylinder comes alive ... that should help decide if it is a petrol or electrics issue

That's a good idea. The misfire got better, it only happens now under high load around 12000rpm high gear and only for a split second and sporadically.

You didnt say at 12000rpm before.

That sounds like fuel starvation.. perhaps fuel vaccum pipe is collapsing at high rpm, does it stop if you back off the throttle for a second?

[krisztian_andre]

It only lasts for a split second, it's more like a sudden loss of power then recovery, and it occurs only sporadically, usually after riding it hard.

[tigerclaw]

Be very careful that your fuel mixture is correct, leaning out at high rpm can cause power loss (this may or may not be what you are feeling), but it ups the cylinder temperatures and can cause piston damage or maybe heat seize... I think you need to put that bike on a Dyno to make sure

[Cammo]

Random idea - but try and run it with the airbox off and spray a little fuel into the cylinder (plastic spray bottle or similar), see if the cylinder comes alive ... that should help decide if it is a petrol or electrics issue

That's a good idea. The misfire got better, it only happens now under high load around 12000rpm high gear and only for a split second and sporadically.

You didnt say at 12000rpm before.

Yeah that would've helped diagnose the issue!

Your bike is lean - main jets are too small for your setup: viewtopic.php?f=24&t=41702&p=306118#p306118

Fit a standard honda air filter, 118f/120r jets and the issue will be gone. Simples.

[Jac-al]

where u from in SA tigerclaw

[tigerclaw]

Hay Jac-al... Close to you I reckon :) I stay in Sundowner (near northgate) ... where do you stay?

[Jac-al]

East Rand. Who and where do u go riding tigerclaw?

[tigerclaw]

I'll PM u

[krisztian_andre]

Now it started misfiring all the time, cold and hot, all rpms. pulling in the choke only makes it worse. I doubt that's because it's sligthly lean.

[Phil Norton]

Did you change the coils yet? They tend to start playing up only when they get hot, but then get worse over time.