PWK- mixture screw seeps gas?

[3wheelrider]

My PWK carb seeps gas SLOWLY from the air/fuel screw & does it while sitting over time (not running)- It hasnt been fiddled with excessively either. And seeps even at 1 turn open. Ive searched the net & found a few other cases on different carbs tho?-but no answer as for the cause or solution. -Do I replace the screw???-dont think thats it ......Theres no washer or O-ring. Cant really seal up the threads -Tho I dont mess with the adjustment really.
I'm sure someone here has seen this before......lol

[El Camexican]

Providing your fuel isn’t on and your float needle isn’t leaking and allowing your engine to fill and spill fuel into the air box there is no reason that that screw should leak gas as it is on the air side of the carb. Granted a little fuel will make its way back into the air box especially if your reeds are worn, or even if you just tip your bike while riding. I am guessing that all you are seeing is residual oil that has settled down into the orifice that the needle tip lives in and has started seeping past the screw threads. No biggie, my brand new 38 AS has all kinds of oil and fuel residue on it after a long ride.

[oscarmayer]

w.o the oring and washer it can leak.i would ensure you get a rebuidl kit and use the new parts to repalce the ones your missing or are bad on your carb.

[El Camexican]

w.o the oring and washer it can leak.i would ensure you get a rebuidl kit and use the new parts to repalce the ones your missing or are bad on your carb.

I haven't pulled a screw out of one for a long time, so I can't swear to this, but I don't recall a washer or O-ring and I don't see any on the diagram I looked up. Fuel screws need seals, but this is an air screw making a perfect seal less critical.

[3wheelrider]

Right- No washer/o-ring on THIS carb. Yes I do leave the petcock on but no overflow anywhere or smell of gas in my shed.

Update: El Camexican was right!! It was more OIL than it was GAS. (I assumed it was GAS- so sorry for the confusion.)-I pulled off my filter (Airbox dry-Filter not soaked) & it was wet/oily in the intake tract. Was reddish on my fingers (KLOTZ)- but no gas smell. So it must be the reeds as he said- residual oil is running down the tube into the orifice for the screw. I'm relieved my carb is fine! Reeds are 4 yr. old VF3 that have original petals. I know-I know.:lol: Not sure about getting new petals cause the damn cage wears out where the petals contact since its a composite material. Not made to last long -but I'm not about to shell out $150+ for a new cage again either so its gonna have to get new petals alone.


Thanx EL Camex!

[El Camexican]

Right- No washer/o-ring on THIS carb. Yes I do leave the petcock on but no overflow anywhere or smell of gas in my shed.

Update: El Camexican was right!! It was more OIL than it was GAS. (I assumed it was GAS- so sorry for the confusion.)-I pulled off my filter (Airbox dry-Filter not soaked) & it was wet/oily in the intake tract. Was reddish on my fingers (KLOTZ)- but no gas smell. So it must be the reeds as he said- residual oil is running down the tube into the orifice for the screw. I'm relieved my carb is fine! Reeds are 4 yr. old VF3 that have original petals. I know-I know.:lol: Not sure about getting new petals cause the damn cage wears out where the petals contact since its a composite material. Not made to last long -but I'm not about to shell out $150+ for a new cage again either so its gonna have to get new petals alone.


Thanx EL Camex!

Good to hear. I would not change the reeds unless they leak as it is the nature of a 2 stroke to push a little fuel back into the carb before the reeds seat. Do you know how to check them? My one and only experiance with Vforce was not good. They (Vforce) blamed the damaged CF reeds and cage on Mexican gas (Most Mexican gas is processed in the USA, it dosen't get its bad rep untill it sits in leaking underground tanks for months on end). Anyway, the test involves sucking on the intake side of the cage and if air passes the reeds they are toast. Make sure you clean them up good first or you'll get oil all over your face.

If the leaking screw bothers you try puting some heavy high temp grease on the screw threads, that might hold the oil back.

[3wheelrider]

OK -I assumed some residue was normal but it must be excessive? I looked at the reeds months ago by holding them to the light & theres gaps. But gonna have to try that vacuum test somehow.-Wait!-With your mouth? How will it get on my face?-:lol:-Bike runs fantastic tho! Surprised a new Raptor 700 the other day with my very mild setup...:naughty: Runs good for what it is.....

Lets say reeds do NOT seal under vacuum...Besides my seepage issue- What are the other side effects usually? Lost efficiency, power? ?
Is idle affected directly? How do you usually know when theyre toast without the test?

Oh yeah-great Buckwheat pic in your avatar-LMFAO

[El Camexican]

Yea, with your face, as in clean it up, push it into your face as hard as you can and suck. If it’s leaking around your face push harder till it seals:lol: There is another way and perhaps better if you have a large cage and that is to pull the carb, put your hand over the boot hole and turn the engine over with the reed block in place. If you feel constant pressure as the piston is coming down I would be suspect of the reeds. Suction on the up stroke is normal and very necessary.

While you might see light that doesn’t mean they are bad. Remember that on the down stroke of your piston force is put against the reeds and that causes them to seal against the cage almost instantly.

If it runs good odds are everything is fine and as far as how much 2 stroke oil, fuel or filter oil ends up on the intake side of the carb I wouldn’t worry to much. It’s a messy environment, just as long as there isn’t any dust or sand in there you aren’t hurting anything. I’d just drive it.

Re: Buck Wheat, I like him too. Reminds me of my politicaly incorrect childhood.

[barnett468]

w.o the oring and washer it can leak.i would ensure you get a rebuidl kit and use the new parts to repalce the ones your missing or are bad on your carb.you need the seal on the screw as mentioned. it may be cork instead of rubber since it is for air not fuel.

air screw seal item 30.

http://www.trialspartsusa.com/diagrams/pwk28explodedview.gif

[3wheelrider]

you need the seal on the screw as mentioned. it may be cork instead of rubber since it is for air not fuel.

air screw seal item 30.

http://www.trialspartsusa.com/diagrams/pwk28explodedview.gif




38mm not 28mm. Not exactly the same. Anyway-youre showing me a spring for idle??....This carb does NOT have a seal/washer-just spring/air screw...thanx tho lol

[barnett468]

38mm not 28mm. Not exactly the same. Anyway-youre showing me a spring for idle??....This carb does NOT have a seal/washer-just spring/air screw...thanx tho lolyes i see you are correct, i must get off the bottle or get some glasses.

[Rigaman]

Yea, with your face

That's too funny! You had me laughing El Camexican. I do that all the time to check my reeds. On numerous occasions people have told me I was crazy or stupid. But it works very well.

There is no seal or o ring on the air screw. Just a spring and the screw. Only way for anything to get in there is if the overflow is clogged or if it's oil dripping back down from the air box. If the overflow is clogged and your float valve is bad, it would fill up your motor with gas. You would have a lot of gas all over.