NC30 running on 3.

[richyrd5]

[arsey30]

That's proved the carbs, but I suspected them all along.

Strange that the rears now work [but on the fronts], they will now be a different angle, but the jets are in the centre so the fuel level will remain the same.

[mitchyboy01]

That's proved the carbs, but I suspected them all along.

Strange that the rears now work [but on the fronts], they will now be a different angle, but the jets are in the centre so the fuel level will remain the same.

Yeah just started it up and the front pots (formerly rears) eventually cut out at idle.

[TommyTheGun]

Mitchboy, i had something similar happen to mine once where the back two were not firing on idle but did when i opened the throttle a bit. Before when i had the carbs out i had balanced the butterflies by eye just to get a good starting point until i had them properly balanced. The back two cylinders weren't firing because when balancing by eye i had not opened the two rear butterflies enough, so at idle the butterflies were still closed too much. I opened them a touch more to match the master carb that the idle cable uses, put them back on the bike and they were sorted.
It could be worth a look.

[mitchyboy01]

Mitchboy, i had something similar happen to mine once where the back two were not firing on idle but did when i opened the throttle a bit. Before when i had the carbs out i had balanced the butterflies by eye just to get a good starting point until i had them properly balanced. The back two cylinders weren't firing because when balancing by eye i had not opened the two rear butterflies enough, so at idle the butterflies were still closed too much. I opened them a touch more to match the master carb that the idle cable uses, put them back on the bike and they were sorted.
It could be worth a look.

Hi Tommy,

I balanced the carbs to the master carb and have checked the with a feeler gauge over again. Do you think I should open the rears a little more?

[Cammo]

Mitchboy, i had something similar happen to mine once where the back two were not firing on idle but did when i opened the throttle a bit. Before when i had the carbs out i had balanced the butterflies by eye just to get a good starting point until i had them properly balanced. The back two cylinders weren't firing because when balancing by eye i had not opened the two rear butterflies enough, so at idle the butterflies were still closed too much. I opened them a touch more to match the master carb that the idle cable uses, put them back on the bike and they were sorted.
It could be worth a look.

Hi Tommy,

I balanced the carbs to the master carb and have checked the with a feeler gauge over again. Do you think I should open the rears a little more?

There's little point if the cylinders don't start firing when you wind the idle up a bit (since that is just opening the butterflies a bit more).

[TommyTheGun]

Mitchboy, i had something similar happen to mine once where the back two were not firing on idle but did when i opened the throttle a bit. Before when i had the carbs out i had balanced the butterflies by eye just to get a good starting point until i had them properly balanced. The back two cylinders weren't firing because when balancing by eye i had not opened the two rear butterflies enough, so at idle the butterflies were still closed too much. I opened them a touch more to match the master carb that the idle cable uses, put them back on the bike and they were sorted.
It could be worth a look.

Hi Tommy,

I balanced the carbs to the master carb and have checked the with a feeler gauge over again. Do you think I should open the rears a little more?

There's little point if the cylinders don't start firing when you wind the idle up a bit (since that is just opening the butterflies a bit more).

Worth a try though, maybe balancing properly using the proper tool by vacuum would sort it. Do they fire when the idle is would up fully?

[arsey30]

I am still unsure from your posts if the poor cylinders do/do not cut in at higher revs/throttle opening.
Do they fire at 2000rpm plus, are the pipes hot if the engine is revved hard a few times?

[mitchyboy01]

No they no longer come in when revving in neutral apart from the odd pops. On the road all 4 pipes get hot but the longer I ride the worse the problem gets. Very strange. Every passageway in the carbs is clear. I've checked them over and over again. Bloody thing!

[arsey30]

Does fuel flow full bore through the tap/hose, and is it clear to both pairs of carbs.

All cylinders fired with carbs reversed, was the position of the tank a factor, how did you maintain a vacuum to the tap and seal the vacuum hose from the port.

Set up a dummy tank or funnel in the fuel hose to prove the tap is/is not working fully.