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Re: NC30 misfiring when hot

Posted: Wed Apr 10, 2013 5:19 am
by Neosophist
krisztian_andre wrote:
tigerclaw wrote: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?

Re: NC30 misfiring when hot

Posted: Wed Apr 10, 2013 12:16 pm
by 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.

Re: NC30 misfiring when hot

Posted: Wed Apr 10, 2013 5:33 pm
by 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

Re: NC30 misfiring when hot

Posted: Thu Apr 11, 2013 12:26 am
by Cammo
Neosophist wrote:
krisztian_andre wrote:
tigerclaw wrote: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. :peace:

Re: NC30 misfiring when hot

Posted: Thu Apr 11, 2013 8:28 am
by Jac-al
where u from in SA tigerclaw

Re: NC30 misfiring when hot

Posted: Thu Apr 11, 2013 4:19 pm
by tigerclaw
Hay Jac-al... Close to you I reckon :) I stay in Sundowner (near northgate) ... where do you stay?

Re: NC30 misfiring when hot

Posted: Thu Apr 11, 2013 6:06 pm
by Jac-al
East Rand. Who and where do u go riding tigerclaw?

Re: NC30 misfiring when hot

Posted: Thu Apr 11, 2013 9:04 pm
by tigerclaw
I'll PM u

Re: NC30 misfiring when hot

Posted: Fri Apr 12, 2013 9:25 am
by 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.

Re: NC30 misfiring when hot

Posted: Fri Apr 12, 2013 10:06 am
by 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.