Scooterotica

I'm running an 'ali' 185kit, 42mm clubman, through a 24mm PWK carb breathing directly. My jetting is 34 pilot, 116 main, JJH needle on middle (3rd) clip. The 2 problems I have are; on 1/4 throttle it holds back and takes off, holds back, takes off (as if breaking on and off) if I accelerate through this it's OK. I have experimented with the needle clip in different posistions, with no real improvement. Plug colour is OK.
The 2nd problem is it spits quite alot of fuel out the carb mouth.
Any advice appreciated.
Dave

Download and read the section on the SCK lammy catalogue.

http://data.scooter-center.com/download ... 2007_E.pdf

Try this link, page 73 onwards.... one of the best easy guides to setting up a carb I've found, and the example they give is for the PWK.

Follow their methodical method for setting up the carb, going from tickover and upwards.

Try a JJK form scoot RS Europe, just a few quid.
It's leaner at 1/4 throttle which may help, this is the needle I use to clean up the bottom end a touch.

djh66 wrote: on 1/4 throttle it holds back and takes off, holds back, takes off (as if breaking on and off) if I accelerate through this it's OK. I have experimented with the needle clip in different posistions, with no real improvement. Plug colour is OK.
The 2nd problem is it spits quite alot of fuel out the carb mouth.

That sounds like a weak spot, your pilot sounds about right and if raising ther needle didn't cure it then try a larger main. In theory the main shouldn't affect below 3/4 throttle but in practice it certainly does as all circuits in carbs overlap each other. Beware though of compensating for an air leak, make sure that the manifold to cylinder joint is sound and that the rubber is sealing properly.

Spit back is always a problem to some extent, my Mugello makes a horrible mess if I run it open mouthed anbd it's a bugger for warm starting if I use a remote filter, it's caused ny overlapping port timings