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750 k6 carbs

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Bitsa (Ralph Wright - RIP):
Hi to All,
Can anyone suggest a cure to my problem?It is doing my head in, totally restored sonic cleaned, completely renewed internals, timing, balance all spot on.
From cold runs spot on until its warm.When coming to a stop with throttle shut ticks over great go to pull away and she stutters and then goes like a rocket all through the rev range until you stop again.At first I thought it could be weak mixture but from cold its fine and I think if its weak it would jerk about but it does not.Plugs colour grey to tan not white or black.Apart from this problem its as good as I can remember back in the 70s when I had a k2.Everything from the head to the rear of airbox has been renewed.The carbs are off a French model k6 and the motor is US k4.I am open to all suggestions.
many thanks

Seamus:
Does it have the original needles? I understand that the aftermarket Keyster ones do not work too well in the CB750, something to do with a slightly different taper.
Info from Hondaman's book suggests replacing the size 38 pilot jets with 40's. Some K6's had these but worth a look.
Float level is also a point to check.

Bitsa (Ralph Wright - RIP):
Hi seamus.
Thanks for that,no they are the new keysters and I had to raise them one notch to stop them sticking slightly.Slow jets are 40s already and I did the float heights with a Honda gauge to spec 26mm if I remember right.The air screws at best are only a half turn out anymore and the tickover starts to mess about.I have also tried 105 and 110 main jets same problem.
Many thanks
Bitsa

Seamus:
Have you still got the old needles. If so, give them a try.

K2-K6:
If you wind the airscrews out further does it sound rich and hunt about as if it's on choke?

If that is so it could be too rich on slow circuit as this would clean up when you raise the revs and engine load.

Thought most air screws are usually 1 to 1.5 turns out to start with.

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