Hi there,i've got Keihin CV carburatores on my super four '93 and just can't get proper mixture from them.Even if i remove the air filter still there's a black smoke when i rev from the exhaust .the fuel consumption is about 10l/100km... .The carbs are perfectly cleaned,with proper jets,fuel level is ok and at the moment i blame jet needles for my problem.The thing is they haven't got settings ...is that so? There are washers that i've removed(moved the jet needles little bit down) and the engine feels better since than.
I doubt if the jet needles are original.In every jet needles kit for keihin that i've checked there are several positions in leveling the needle(not with mine).The bike is Japan import and i just can't be sure about anything.
You may say to buy some needles and try,but don't know what to order.There are hundreds numbers of needles and none of them has close sizes(may be i just couldn't find my model by now).And the other thing is i live in Bulgaria and it's not easy to order things from here .ANY IDEAS?ANY..???

P.S
I'm pretty sure about engine condition-the compresion ratio is between 12 and 13....

I'm not sure but i'm almost certain that a 13:1 air to flow ratio is right on the money ! Is the black smoke possibly caused by oil getting into the engine some where??

Well,smells like fuel(not oil) and i miss only fuel .And about mixture screw i think it's working only with slow jet emulsion pipe(correct me if i'm wrong)

I had mixture problems with My SF when i got it first. The previous owner had the carbs set up for racing. I took it to a carb specialist and got them re-adjusted and balanced. Never had a problem since. Ask around for a motorcycle mechanic who will adjust and balance the carbs for you. This should solve your problem.

Frank.

Well,thanks for advice....maybe i'll do it at the end. But i feel close to solve it.There's almost nothing you can play with mixture except jets and jet needles(air jets are fixed) and as it seems at the moment mine are fabric.A friend of mine told me that is possible because of bad quality fuel(which is constant for my country )for the jet halls to become bigger.I'll try to change them and see...Anyway,i'm open minded for any ideas.

Problem was electrical...it was regulator-rectifier.I've put now dominator's one.It was the closest i could find like the generator coil resistance.Let's see...

Still my problem is going on...and more i look more i think someone changed the jet needles.mine are-j4bf.is it possible for anyone to see his?