NC30 running on 3.

[mitchyboy01]

Well my theory didn't work lol.

So back to basics and had the carbs off again and I'm 100% sure the pilot circuit is clear. Bike still won't idle below 2k and the rear 2 cylinders only fire the odd pop here and there.

If I run the bike with the vacuum hose for the tank venting to atmosphere and spray carb cleaner into the pilot AIR jet (by the needle diaphragm), the non firing cylinder would fire. Not sure what this means?

Took the bike out and on hard acceleration all 4 kicked in and the bike felt strong. Let it idle again and back on the front 2 cylinders. When warm the choke would no longer make the rears kick in. After a thrashing it would begin to run badly even on WOT.

Reading other threads where people had similar running problems all the solutions were quite simple: Plugs, leads, pilot circuit blocked etc. Why is mine such a pain in the ****!!

[mitchyboy01]

This issue could also possibly be caused by throttle butterflies needing synchronising. i.e. cylinder 3 butterfly may be fully closed at idle.

To eliminate this as a cause you could try increasing the idle speed (via adjustor) to about 2000 revs. If the bad cylinder starts firing consider synching the carbs.

Hi Cammo,

I did bench sync of the butterflies using a feeler gauge. I read that most people use a drill bit but I couldn't find one small enough.

[richyrd5]

have u tried new plugs?

[mitchyboy01]

have u tried new plugs?

Yes, and leads, swapped coils around, etc etc

[bikemonkey]

Is there anyone you know that's close to you and can swap carbs?

Might give you an idea?

[mitchyboy01]

Is there anyone you know that's close to you and can swap carbs?

Might give you an idea?

There is a guy on here who has kent in his sig but ive not been on here long enough to get to know who's from where. No friends near me I'm afraid.

[arsey30]

The bike will not idle below 2k if the 2 rears are not working.
Vacuum hose will draw air into cylinder [weak ] if disconnected from the tap or inlet port.
Choke will not work well on a warm engine.

So, it now looks like the 2 rears are not working well.

[mitchyboy01]

The bike will not idle below 2k if the 2 rears are not working.
Vacuum hose will draw air into cylinder [weak ] if disconnected from the tap or inlet port.
Choke will not work well on a warm engine.

So, it now looks like the 2 rears are not working well.

It's just confusing as no.3 wasn't firing at all. Removed vac hose and sprayed in carb cleaner to the air jet and it started to fire. Why doesn't it fire normally. Bloody bike. Neighbours must think im mad. Carbs off, carbs on, scratch head. Repeat 4 x per day 3 days in a row. Is this borderline madness?

Just spoke to my dad about it and he jogged my memory that when we started started it when I first bought it wasn't firing on the front right cylinder. How can a problem keep swapping cylinders? Im just confused. Will buy some matches tomorrow

[richyrd5]

if u spray into carb and it starts to run its gota be carb or maybe inlets/carb rubbers maybe.wat condition sre they in.are the bottom clips tight.??

[bikemonkey]

I think it's a carb passage blocked.

If anyone could lend you a set of carbs to test that might help massively.

Put a wanted ad up in the parts wanted section asking to borrow a working set, I'm sure someone will be willing to help.