[39mm PWK carb jetting] - ATV Riders Forums - Honda, Yamaha, Suzuki, Kawasaki, Polaris, CanAm, Arctic Cat, Kymco ATVs

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39mm PWK carb jetting
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Posted by: 2StrokeGod

I just bought a PWK 39mm carb and need jetting help.
My 250r is stock exept paul turner race pipe and cr250 rad valve with no air box lid. curent jetting with stock carb is 160 main 48 pilot and needle in 3rd clip. The guy i bought it from is local and ran it on his 310 jetted with 172 main 55 pilot and dgj needle in 3rd clip. Any help on a starting point on jetting would be apreciated. And will the stock cable work on it and im asuming its a 39 but heres what it says on carb PWK 72ra4 neh.

Altitude 2000 tucson arizona.

Posted by: 2StrokeGod

Need help ASAP.

Posted by: wilkin250r

I can't really help you. There are many different factors to jetting, like engine size, carb size, reed type, filter type, porting, altitude, ect.

I've never run a 39mm PWK on a stock-bore motor with a CR reed cage. So I don't know where to start with jetting.

It's very likely that someone on this board has run a similar setup, and can give you a starting point. But we aren't all sitting on the computer waiting for your beck and call. Give it time, it may even be a couple days.

Posted by: EXtreme-

the 72r is definately the pwk39. Trial and error time

Posted by: DPR250R

Drop to a 50 pilot.

Up the main to a 175.

The needle is OK... but you may want a CGJ if you can't get it right.

From there.... do your normal plug chops... etc....

This is only a starting point....

Posted by: sandspanker

in my 350 I run a 60 p dgk needle middle pos. and a 172 main. the big bores draw more fuel then a stock cyl. thus the smaller main.

Posted by: 2StrokeGod

Alright this is what im thinking of starting at 172-170 main cel needle one clip up from the middle with a half step spacer 52 pilot and about 2 turns out on air screw.

Anyone have any comments lets hear em.

Posted by: 2StrokeGod

Almost forgot will stock cable work or will i need to get a diferent one if so what one.

Posted by: beerock

quote:
Originally posted by 2StrokeGod
Alright this is what im thinking of starting at 172-170 main cel needle one clip up from the middle with a half step spacer 52 pilot and about 2 turns out on air screw.

Anyone have any comments lets hear em.

a half step spacer? under the needle clip? i dunno about that sounds like something else for the carb to suck into the motor

Posted by: 2StrokeGod

This is where i ended up with 170 main cel needle in middle clip with half step spacer under the clip, 50 pilot with 2 turns out on air screw. I may be a little fat on the main and needle but with winter coming it should be ok.