139qmb 2006 key west 50cc moped (Help Needed!) Witts End.

[madisonmarineman]

backing off or changing throttle doesnt do anything, its a constant popping that doesn't change from half to wot, it looses all further power at that 50% range. doesn't seem to do it on a stand only under load. if i go wot from sitting it pops but reaches 15-20mph but then popping completely drowns out and any further gain in mph is gone. I noticed that introducing more air by removing filter slightly helped but not enough. Slightly closing valves from .0055 to .004 had no effect last night.

i am leaning towards the vacuum fuel release/pump limiting fuel causing this running issue.

i read through the complete carb adjustment on this forum (WHICH IS IN DEPTH AND A GREAT RESOURCE) and feel confident geting it dialed in tonight, i am almost out of time.. I am changing to a on/off petcock tonight hoping i ordered the right one which i am fairly confident i did.

If i get it dialed in i am replacing brakes + puting on improved variator/clutch before sending it down the road.

I will report back

[madisonmarineman]

Update:it runs 35-40mph. It was running way to lean. It likes to currebtly only start on kick start when cold. Where should I turn idle air for lean condition Main jet change to .80 made a difference. I wanted .82 but didn't have it in kit. The fuel venturi pump was not working that great. Changed to petcock and closed off vacuum line. I'm wondering if I have the valves just a touch to tight but not willing to adjust again after coming this far. Starts best with throttle open it's one kick. It's currently 70f. I'm wondering if it will run as good as it is now at 50f. The top needle I tried a few positions on the notches but didn't seem to make a huge difference mid range.. Im 2 down from top atm.. Also I swear the cap is slightly plugged. I kept the cap off last night while dialing in the carb. Replacing that and the belt tomorrow night before I send it off to aimes Iowa sat am.

Also note. The spark plug i used was so cheap it was blowing through the plug. Swapped to oem plug...lots of things were not ideal. Stock air box is on. Have to use it . Runs to lean as it was.