Out of ideas and ready to break!

[CharlieK]

I still cant get my NC30 running right, its driving me mad. I took it to have the carbs balanced last week and a week later the mechanic announces he can't manage it because he can balance the front two cylinders and the rear two but as soon as he tries to balance front and rears together it throws the the pairs out. I got it back worse than it was when it left and 50 lighter, fucking irritating. I got it home had the carbs off again, rechecked float heights, needle seating, cleaned the slides, reset the screws to 2.25 turns out, everything thats recommended. When ridden it revs up nicely on low throttle openings, but as soon as you try and open it up with a wider throttle it coughs and splutters and won't pull, as soon as you roll off the throttle it dies on me. (Its not the speedo connector, I have checked that)
I just rang David Silver for a laugh to see what a new set of carbs would be, 1500 quid was the answer!
Anyone got any ideas before I break the bastard for spares, or alternatively if anyone is willing to give up a day and have ago, I'll pay them for it. Cheers chaps.

[mattUKNC]

Something is screaming "electrical" to me!

Where are you located?

[CMSMJ1]

That is fixable... no worries about that..

As Matt says, where you at!

After next weekend I could loan you some carbs that work..try them..but either you have a fecked jet setup or plugs breaking down under load etc.

What have you done to it to try and fix it - and what was the inital fault?

Also, why did you pay the dickhead as it was not fixed? Sod that.....

[ibby4585]

why did you pay the dickhead as it was not fixed? Sod that.....

I agree!! Ive got some carbs you can try and borrow running 115 and 118' jets.

im far from being being an expert, could it be the cdi? ive got a spare standard one of them too.

Kris

[Neosophist]

Where are you located?

Check the electrics first.. a bad earth is going to cause 'carb' like problems.

As for the carbs themselves.

Is your air-filter clean, standard and in the right place, theres no air-leaks around the rubbers?
Your exhaust system is normal?

What do you have the float-heights at (and how are you checking the level)

It sounds rich to me... start with 2 turns out on the pilot screws.

As for fine at tick-over dying at throttle..

Jets / free slides / vaccumn pipe / fuel tank supplying enough fuel / breather blocked?

[CharlieK]

Im down in Northampton, NN141PJ. If anyone with some skills is willing to come and have a look at it Im happy to pay 100 quid to get it sorted. Electrical is an interesting thought,I have read a lot on carbs in this forum and tried everything. Its got new plugs so they are ruled out, the pulse generator and CDI I think are OK, Im not sure about the reg/rectifier, (It's showing 12V across the battery when running) surely that couldn't cause a problem like mine? What about HT leads? I don't know how to test them. The wiring loom on the bike is certainly a weak point, because it was a right old rat bike when I bought it.

[Neosophist]

yeah that would most likely cause very similar problems

12v is no good.

Rev it to 5000rpm and measure the voltage

13.8 or higher or you have electrical problems.

[CharlieK]

Neosophist, in answer to your questions, its got a brand new air filter, the airbox is sealing, the carb rubbers are brand new and seal fine, the exhaust system is standard with a Viper end can, but one of the front exhaust manifolds blows a little bit, I have a new copper gasket but haven't fitted it yet. The carbs are running 118 fronts, 120 rear jets, slides drilled to 2.5mm and needles raised by 0.5mm, the float heights are set to the recommended setting and are correct cos I've checked them three times now. The pilot screws are all 2.25 turns out. The jets were new from Rick O so unlikely to be blocked, the slides are all operating as they should, I stripped and cleaned them all again today to make sure. The breathers not blocked, the vacuum pipe is not snagged and there is a gallon of fuel in the tank.
I hope it is electrical because I have done about all I can to the carbs!

[Neosophist]

On that basis i'll take it as your carbs are in 'working order'

Raising the needles richens the mid-range.. sometimes I find this isn't needed (makes the bike bog more) so it's touch and go.

If it's really struggling to pull it sounds electrical.

Check the voltage like I said.. the bike charges between 13.8-14.4v @ 5000rpm and get back to me :)

[CharlieK]

Just had the ole multimeter out, its reading 14.46V at 5000rpm, that sounds about right.