Carburator setup with my 72cc kit!???

[vermi]

Long time i try to found my caburator problem!
I have Kymco People 50S 4T with a 72cc kit, 6G rollers, original air box and a Tecno exhaust.
My valve are set at .003 Intake and Exhaust. I play with the mix air screw, now is at 1 1\2, my idle is good.
The Pilot jet #35 and a main jet #90 but my spark plug is always dark black (too Rich).
I try a main jet #85, the spark plug look better (lite tan brown) and top speed is around 43~45 mph on the speedo.

Normally we suppose to use main jet #90 or more with a 72cc kit, no?

Plus i always have a little hesitation when I restart after a stop(ruling) or if i slowing down and re-accelerate!?

Is it possible is the choke always on and it make always rich!?

Thank's for help!

[wordslinger]

..you need to replace that airbox with a K&N or similar type free-flow air filter...

[art]

Yes,not enouph air. You are choking it down with oem airbox. You could try a few holes in your box or try running with the cover off to get an idea what you are missing.

[thebatman]

absolutely... i am a FIRM believer in a open air filter now..(ran my oem box for a while too, sux)..jerk that box off and rejet again!!.. itll make a nice difference... (then you want MORE AND MORE)......

[vermi]

I remove the cover of the original air box and i ride the scooter.
The acceleration was faster and i think the top speed was better too.
So i buy ( Uni Filtered Air Vent ) to put under the air box. It help a lot but my little miss in acceleration alway there...
If i start very slow i didn't have the miss in acceleration but if i start fast it's there.
Now the spark plug look lean and the jet is a #100 i try the #110

The last thing is the acceleration pump i think it's the problem!!!
I open it to check, it look fine....

What i do, i order a new carburator today 
I'm tired to open and try to see where the problem come!!!!

What size of jet you think i need, now i have a #100 and always lean?

[thebatman]

are you sure its lean.. metals edges looking oily...if its lean, go bigger...how lean?? if pretty lean jump 2 sizes or just one at a time... see there, big difference w/o that box..lol..try and get a tan mix ring going..leave the stock box off during the rejetting, it will change it... did you try the 110??  outcome was???

[thebatman]

oh yeah, that miss you feel could be your pilot jet or your needle hieght...mine has a similar problem just off idle