Hi.recently purchased a Uk spec nc30.

The problem that i have is that the bike will not rev.

The bike starts and idles.If you throttle slowly the revs will pick up,give it a handfull of throttle and it dies.

I have changed the coils and leads.

cleaned carbs.
checked fuel flow from tank.

I noticed that the jets were the wrong way round 122f and 120r instead of 120f and 122r.

swaped them round but still no joy.

Could this have killed the spark plugs?

Got some new plugs on order.

Will the bike rev without a air filter and lid on or do i need to put it back on to test.?

the bike also has a carbon open air box and foam filter.

Any help would be greatly appreciated.Thankyou

These bikes don't like their intake being messed with.

But first, is the exhaust stock?

Carby vacuum hose fitted and in good condition?

Full Tyga system and fuel tap mod done.

The mixture screws are 1 3/4 turns out also.Thanks

If you have cleaned the carbs correctly most importantly pilot jets,
If this has been done with no improvement then fit a standard airbox and filter.

trevor1 wrote:The mixture screws are 1 3/4 turns out also.Thanks

Wayyyyyy too lean, especially for a full system. Try them 2.25 turns out.

And as above if that makes not a lot of difference then get the intake standard.

Might be worth balancing the carbs too

Your problem is the foam filter IMO. They like the HOnda filter best and there are no gains in my experience in using something other than that.

You absolutely need the bike back together and ideally riding it to test the fuelling. No airbox lid - too lean, no revs

Did you ride it or run up the engine before you bought the bike, if so, has the fault come on since.
Have you done any thing to the bike before the fault appeared?

Also not that this is causing your problem but UK bikes run the main jets the opposite way to JDM bikes so your jets were right in the first place, Ive no idea why honda saw fit to do this but im sure they know their onions.