Please help guys. My nc35 runs great without the tank on now after having the carbs cleaned, but when I put the tank on it runs for about 3 mins and then cuts out and fuel pours out of the overflow tubes. I've connected all the pipes as they should be but just carnt figure it out.

Did you set the float level correctly,if you did and they are right then its the float needle,

When you say the needles is there anyway of setting them or do you mean that they are worn and I need new ones. The guy who sonic cleaned the carbs set them up as well which is a bit worrying. It runs great when the tank is disconnected and the carbs are running on the fuel that is in them all ready.

Does anyone know if there's a good garage in the south Wales area that can set my bike up. I'm really at a loss on this one. I seem to sort one thing out and come upagainst another. Sorry to be so down but I've had it with carbs.

I also think it may be the floats are sticking, as Hunter said before.
Do you feel confident in working on the carbs yourself?
Do you ever get down to Pembs, as i am not a million miles away. I am not expert on carbs but have seen the inside of mine plenty and would be willing to lend a hand.
What jets are you running, and do you know how the guy balanced the carbs?

I got no problems with stripping the carbs but I just don't understand how carbs work. I did set the floats to 12 mm when I stripped them the first time. The guy who did the carbs has about 40 old fully restored bikes so he seems pritty good at what he does. I'm going to give it one more go tomorrow and have a good look at all the settings again. Do you guys always get these issues with carbs or is it that once there set there set?

I think Cammos' carb tunning sticky is a very good place to start for understanding how they work.
If you set the float heights wrong they will remain wrong. It might be something in the carb bowl stopping the float from operating properly.
If it happens next time you try it might be worth stripping them just to have a look.

Sorry i mean worn,or is there crap in the fuel tank,if some crap gets between the needle and seat it will flood,
but it does sound like worn needles,

TROUBLED OTTER wrote:The guy who sonic cleaned the carbs set them up as well which is a bit worrying. It runs great when the tank is disconnected and the carbs are running on the fuel that is in them all ready.

I don't want to sound like a smart arse, but unlesss the guy that set them up is familiar with V4 carbs, I'd give them a good going over - NC35 carbs are a law unto themselves when compared with the usual in-line 4s, etc.

I think it's just a case of going over everything and checking the settings against the specs in the Haynes manual (for a start)

You say it runs well when without the tank on - when you've tried this have you had the airbox fully assembled as it should be?

TROUBLED OTTER wrote:I got no problems with stripping the carbs but I just don't understand how carbs work. I did set the floats to 12 mm when I stripped them the first time. The guy who did the carbs has about 40 old fully restored bikes so he seems pritty good at what he does. I'm going to give it one more go tomorrow and have a good look at all the settings again. Do you guys always get these issues with carbs or is it that once there set there set?

The float height is 6.8mm.

How / where are you measuring the float height from.. it sounds like there overfilling and running rubbish, then as the fuel drains out it starts to run better.