NC30 carby jetting - DIY guide

[webby16]

hi i am thinking of going for the tyga full exhaust system with single carbon can, also thinking of going for the tyga carbon air box to increase free flowing air volume... would the hrc carb kit work with this set up i have a hi flo airfilter fitted aswell?
thanks webby

[Cammo]

hi i am thinking of going for the tyga full exhaust system with single carbon can, also thinking of going for the tyga carbon air box to increase free flowing air volume... would the hrc carb kit work with this set up i have a hi flo airfilter fitted aswell?

Is it a road bike or a track bike? The nc30 hrc carb kit should only be used on track bikes that have no airbox or air filter, it will make the bike perform far, far worse for road riding.

If you were using a genuine honda air filter then fitting a full system would probably require increasing the carb main jets by 1 or 2 sizes. I'm not a fan of aftermarket air filters as they all flow differently and jetting the carbs for them requires a bit of guesswork.

[webby16]

ok thats great thanks for the help so with regards to hrc jet kit il give it a miss i was thinking of road/track bike but i dont fancy having a bike with is a nightmare on the road with regards to ideal and high rep etc! i have had track bikes before and i know what sort of running problems you can have but i just wanted to jen up on the subject.
thanks cammo!
webby

[juggernaut]

I've just done the K&N panel filter mod and have an ART exhaust can on my nc30, I've got a H reg nc30 so there's a good chance it'll be running very lean now if its running the smaller jets the early 30's run.


What kinda sizes should I pop in it now?

Cheers
Luke

[Drunkn Munky]

Jet as per the guide mate, one size up from whats in there for a end can.

[speedy231278]

As per the above, but NC35, with a Scorpion can. Earlier in this thread the advice is that a loud can or half system on a 35 would merit 112s all round, however on the thread about the K+N panel DM suggests that with the can and filter 112s would probably be OTT. I have ZERO experience with rejetting, and I only understand the basics, ie less restriction on air intake and less restriction on exhaust improve flow through the engine, therefore need bigger jets to prevent the engine running too lean. The only deviation from a completely stock setup will be the end can and filter (and the main jets, obviously!).

[Cammo]

The only deviation from a completely stock setup will be the end can and filter (and the main jets, obviously!).

I'm reluctant to recommend jet sizes when an aftermarket filter is used due to the different airflow characteristics, the trial and error often needed can waste your time and money.

Induction changes make far more difference to jetting requirements on NC's than exhaust and other changes.

I've never used a K&N, if it flows exactly the same as a standard filter then 112 jets would be fine with your muffler. If it has a higher flow rate then you'll need bigger jets in there. I don't imagine teh flow rate would be less than standard, but it could?

[speedy231278]

I'm sure it will flow more. I guess I'll have to find someone else that's done it and see what they found to be best. I don't like the idea of buying loads of different sized jets until I find the best size considering that pukka ones are more expensive per set than an air filter! If the jets are too small in comparison to the filter's flow rate, what characteristics will I notice in the way the bike runs? I presume higher air flow plus too small a jet size means it'll run lean? IIRC, while you don't want to be excessively rich either, lean is worse and can cause damage to the engine in the long term or of it's thrashed, whereas too rich will cause the plugs to foul up?

[CMSMJ1]

lean would usually still rev and sound crisp - but will be weak

rich is fluffy and boggy IMO - does not rev out cleanly

In my experience - get it dyno'd to be sure..or be prepared to take some time to sort it and make lots of notes

[speedy231278]

Well, with the current carbs it could already be both of those depending on what part of the rev range you're in, when you change gear, what the air temp is like.... hence why I want to sort the bloody thing out with the 'new' carbs. I guess if I got someone to tune it on a dyno, what I lost in money on their time, I'd save a little back on sets of jets....