Keihin PWK question

[Caddy 16v]

Hi,

my fuel mixture screw (pilot air) fell out of my carb while riding and I want to replace it, while searching around I found some aftermarket ones, but one says PWK 28 but I believe I have the PWK 38 in my KX250, I'm pretty sure the screws are all the same from 1988 on and are from KX85 - KX500 !?

I just need some reasurement from you guys

Here are 2 links:
http://www.splatshop.co.uk/jitsie-pwk-28-air-mixture-screws.html

https://www.scooter-center.com/scoweb/pages/productdetail.grid?product=288939112192608&target=productdetail&category1=C&category2=CAT

Thanks, Bjoern

[byron909]

all keihin flat side carbs run same air screw.
 so all pwk 28-41, pj 34-38, pwm 38.
make sure you have spring for it as well.
a dab of liquid thread sealer helps keep it there. the kind for pipe threads, not loctite kind of stuff.

[Caddy 16v]

Thanks, that was the info I was looking for! Do you have a product name for that thread sealer?

[don46]

I would NEVER put any sealer on my air screw threads, don't do it, it doesn't need anything. besides the screw, there is a spring, o ring and washer. And remember the screw is only turned out 1/14 to 2 turns out so there should be adequate pressure on the screw, I have never had one back out, I have worked on carbs that the screw wouldn't come out and in many cases they ended up getting new bodies.

[Caddy 16v]

My screw was all the way in when I got the carb, so I went ahead and turned it 1.5 turns out and went riding, after the ride it was gone grrrr, I suspect there wasn't even a spring in there as that carb had also the throttle stop screw missing.

I took the mixture screw and spring out of my other bike for now but will order some replacement soon.

[byron909]

on keihin carbs there is not a washer or oring at air screw. some oems had them on their stuff but you could not buy. if you have an aftermarket keihin it will only have a spring and the actual air screw. every bike i own has some form of a pwk, and every bike gets real dirty around the air screw area, like there is a leak. installed oring/ washer, no help. have had many come loose as well.  i put a tiny tiny dab of loctate 592 on the screw just to keep it there, and it also prevented the dirty mess i always see. the stuff does not dry, it just get tacky. you can still adjust screw no prob. i guess some of my carb bodies are worn at the threads or something. even tried longer spring, stretching spring, etc.
anything can freeze up, all in how you take care of it.

[don46]

on keihin carbs there is not a washer or oring at air screw. some oems had them on their stuff but you could not buy. if you have an aftermarket keihin it will only have a spring and the actual air screw. every bike i own has some form of a pwk, and every bike gets real dirty around the air screw area, like there is a leak. installed oring/ washer, no help. have had many come loose as well.  i put a tiny tiny dab of loctate 592 on the screw just to keep it there, and it also prevented the dirty mess i always see. the stuff does not dry, it just get tacky. you can still adjust screw no prob. i guess some of my carb bodies are worn at the threads or something. even tried longer spring, stretching spring, etc.
anything can freeze up, all in how you take care of it.

I don't mean to say that you don't know what your talking about, but, you don't know what your talking about. Since this is a kawasaki forum I'm talking about kawasaki, and they DO have a spring oring and washer. and to go further I don't think I've ever seen a carb with out a sproing on the air screw. 

Since you might need to find some I've attached a diagram so you can order the parts that should be in there.

[Caddy 16v]

The carb that I have doesn't have an o-ring and washer, just a spring, it's a 88-93ish model:

 

[kaw rider]

if i had to guess that o-ring is not shown because its not a replacement part from kawasaki.

[byron909]

don thanks, but like i already said some have, some have not. your diagram looks like 99 up kx125/250 carb. it was a pwk, the bore, hole whatever for screw same as any other keihin. look at same carb for yz, it won't have. but then old pj from honda will, newer pj from late 90s won't.
every pwk i have ever removed from kx250 or kx500s didn't have washer/ oring
if you buy new carb from cpw, sudco, it will not have, and if you try to buy they will not have part number, but is same washer/ oring as late model fcr 4 stroke.
go figure