NC30 carby jetting - DIY guide

[Jac-al]

tell me i put somwpe other jets in my bike will it matter? they fit obviously but are a little longer and fatter that the original, they dnt have a name stamped

[Jac-al]

?? pls anybody reply, i wanna know before i pop carbs back in

[CMSMJ1]

of course it matters! But you'll not know how much til you try it

[Jac-al]

put them in, when i rev its very rough and battles to go over 8k rpm, guess they arent compatible, oh well have to change back again

[Cammo]

The shape of the jets shouldn't matter, they come in a variety of shapes from different manufacturers.

I'd suggest if you're unsure about this then it's best to leave the carbs alone and perhaps take it to a professional.

The symptoms you describe are not applicable to most minor jet changes.

[Jac-al]

i know how to do the carbs, ive done it plenty, was just wondering if the shape would make a difference as ive been told. also cause its just been behavin odd sinceci changed from 110's to 120's. thanks for ur concern

[Neosophist]

i know how to do the carbs, ive done it plenty, was just wondering if the shape would make a difference as ive been told. also cause its just been behavin odd sinceci changed from 110's to 120's. thanks for ur concern

Cammo is one of the most helpful and knowledgable people on the site, you'd do well to listen to his advice.

If you know how to do the carbs surely you wouldnt need to be asking questions right?

First off why did you change to 120s? Is your exhuast and airbox standard?

If your in south africa you could be at a high altitude, which is great with smaller jets and awful with larger ones.

A longer jet will make a difference to the fuelling as your changing the float height but it shouldnt make it unridable unless you really cock the jets up.

Based on other members id say due to altitude you need the smaller jets.

But please post up why you thought it would be good to change the jets (any problems before?) and if the bike is standard.

[ant_v4r]

Cammo is one of the most helpful and knowledgable people on the site, you'd do well to listen to his advice.

Maybe there should be a Cammo Service and Repair Manual! haha
(I'm looking at getting a Tyga twin stack full system when I've got another couple hundred quid... any help on where I can get a new high performance air filter from to match the high performance race exhaust? I've looked about a little but not found much myself... I was suggested to look at K&N but they don't do them any more. Maybe you or Cammo have a specific place you'd each recommend?)
I'm glad I'm randomly browsing the site though, this will be a massive help for when I have to re-jet after getting my new parts! I thought my old RS125's jet was a pain... now there's gonna be four of them! but this time, I have a little experience with carbs and I have what seems to be a great how-to!

[CMSMJ1]

^^ Honda air filter is as good as you get...

[Cammo]

^^ Honda air filter is as good as you get...

+1

Please don't use anything but a genuine honda air filter, it just opens up a can of worms when it comes to jetting and midrange driveability usually suffers.