Need help w/39mm PWK

[Chevy454]

Little bro picked up a *worked* R with a 39mm PWK carb on it...when we got it home and finally got it started it ran like CRAP, so we spent the afternoon playing with the jetting and such, and it will at least take the throttle now, but the thing refuses to idle. We sorta played with what appear to be 2 adjustment screws on the left side of the carb, but I was reluctant to do too much as I wasn't for sure what either one effected? I would appreciate any & all advice anyone can lend on helping to straighten out, as there is a race this weekend...thanks!

[450RGNCC]

have you cleaned the carb yet? If not, thats your best bet, if that doesnt work, make sure the reeds aer not broken and are in good condition. One screw is probably the idle screw, does it go in near the top of the carb? the other one is the air screw. best way to set air screw is go the whole way in and move it out 1/2 turns until it idles the best. dont be afraid to mess around with the adjustments, you can always put them back to where they were. good luck.

[Chevy454]

Many thanks...I know my way around a Holley 4-barrel but these little boogers are new to me! The scary thing is the bike is FLYING even with the carb not dialed in!

[wilkin250r]

It's been a while since I have fiddled around on the PWK, but I'm almost positive that one screw is an air screw for adjusting the idle mixture (along with pilot jet size), and one screw is for idle speed adjustment.