Can anyone tell me the amount of turns out i should be setting( or starting with) my mixture screw to. Carb is a phvb 20.5 and the mixture screw is a 2.2mm with a spring only (no "O" ring) I have tried it at 1 and a quarter but the scooter sounds crap (4stroking) at anything under 35mph. It gets better the more I turn it out and is really smooth at 2,1/4 to 2,1/2 but it just seems a bit far out to me . slow running jet is 50 and main jet is 90. standard airbox used. Any advice would be helpful ps is the part on the airbox side of the carb with the two electrical wires coming from it, a carb heater or an air temp sensor for the auto-choke?
turn scooter on, set the idle high so its revving higher then usual at idle. Then play about with the air/fuel mixture so its revving at its most on that set idle point. Then turn the idle back down.
Thanks for the reply M.R , that is how I would usually do it ,but just thought I would ask as I have found so much conflicting data on runner/dragster carbs, jet sizes,etc and wanted to be on the safe side. :nerd:
If it Four stroking then its defently to lean. Richen it up (screw it out). Try checking the plug colour aswell. try to get it a nice light brown. If its a dark brown then it may be too rich. Dont Go near White!!! Its too lean!
