My 3rd carb rebuild, and still it is super rich, help me get out of this misery!

[HamadUP]

I'm trying to start up my '86 ATC 250R using its original carb and two other replacement carbs, they all share the same problem : super rich!, its so rich that I can't keep it idle (I need to open the throttle aabout 1/8 up), and the spark plug will get gas soaked instantly, I tried to rebuild all three of them using the factory jets but none of them seem to fix the problem. As soon as I put in the carb out of my '85 250R it started right up and ran very well. I can't seem to find what causes all three of them to be that rich, obviously I'm doing something wrong, but what is it?!! Here are some pics of the rebuild and some info about the setup :

main jet : 145
slow jet : 42
needle : 3rd groove
mix scree : 2 1/4 turns from fully seated
idle scre : 24 clicks (4 turns) from fully seated.

Please let me know if you see anything wrong with these pics :

[huskydave]

when you clean a carb clean the whole thing not just the internal parts (yours looks dirty on the outside) because when your assembling it you may get some dirt inside. Soak the whole carb in a degreaser with all your jets etc... then take a small wire a torch tip clearer works well and clean all the little holes on your jets. Blow compressed air through all the passageways along with carb cleaner . I would be willing to bet you either have some dirt left in one of your passages or you have some varnish in there still. The best way to clean a carb is with an ultrasonic cleaner some small engine shops will do it for you for a few bucks or you can buy one my 2 cents.

[HamadUP]

when you clean a carb clean the whole thing not just the internal parts (yours looks dirty on the outside) because when your assembling it you may get some dirt inside. Soak the whole carb in a degreaser with all your jets etc... then take a small wire a torch tip clearer works well and clean all the little holes on your jets. Blow compressed air through all the passageways along with carb cleaner . I would be willing to bet you either have some dirt left in one of your passages or you have some varnish in there still. The best way to clean a carb is with an ultrasonic cleaner some small engine shops will do it for you for a few bucks or you can buy one my 2 cents.

These pics were before cleaning everything in this carb to a brand new look. I'm still scratching my head looking for where the problem might be!, its even more weird that all 3 carbs did the exact same thing, and I'm sure its the carb because when I used the carb from my other bike it ran very well.

[onformula1]

Check the float levels and if you did, double check.

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[ironchop]

Is the enricher adjustable on a PWK?

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[onformula1]

Is the enricher adjustable on a PWK?

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No, but that is a PJ

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[ironchop]

Sorry....typo

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[Tri-Z 250]

Sell all the old ones buy a New one CPW www.carbparts.com

If I was to guess its the float level and spring. Soak floats outside test to make sure they float. You try the bunk carb on the other machine? If it runs just swap em! Lol

[newby200x]

Any difference if you move the needle clip to lean it out?

[jb2wheels]

3 different carbs and the symptoms are the same?

Carbs aren't the problem. Time for a pressure test?

[huskydave]

Float level could be wrong or needle may not be fully seating. Did you change the needle and seat? Don't bother with a leakdown test if you had an air leak you would be running lean. Take the carb off drain it and turn it upside down blow through the fuel inlet you should not be able to hear any air going through that will tell you if your needle and seat are good. The only other thing it could be is float level, wrong jets or dirt/varnish. If your needle is sealing good I would lower the float level slightly and see if it helps.

[shortline10]

I have run into this problem several times on the 86 250r stock carburetor . First trying a carburetor kit which did nothing to help with the idle . My best advice is to just buy a new 36mm Keihin and your problem will be solved .
I wish I had the answer of why these 86 carbs have this issue but I don't .

[atc007]

^^ Ditto, leakdown test, new carb, 20 more years care free.

[HamadUP]

I just spent about 5 hours trying to get that carb to work, here are the steps I did today :

- Disassemble the whole carb and cleaned everything very well again.
- blow compressed air in EVERY hole in the carb.
- Assemble it VERY carefully, exactly as instructed by the '86 shop manual.
- checked the needle/seat, did the blow test and it was working fine.
- set the air screw to 2 1/4 turns.
- install it, run the trike, same thing, VERY rich and wont idle.
- tried all the needle clip positions, no change at all.
- checked the float level again, checked the needle/seat again, all were good.
- installed the '85 carb again, and the engine ran very well again, so it MUST be the darn carb!

I just can't believe that all '86 carbs are bad!, they must be good at the time they left the assembly line, so what I'm doing different here?

I get inside the house coming from the garage everyday and smell like an open tank of gas!

[YTZ drew]

I have never had a PJ carb apart, but I've been into a few PWK's, and more round slides than I can count. See those two Torx screws that hold the jet extension into the main body? I will guarantee there is a formed o-ring type gasket in there just like on a PWK. If that gasket degrades it will be impossible to get the carb to perform properly. Sudco might be able to get that gasket for you. Also, I second the notion that you need to clean that carb more thoroughly. I'd suggest 24 hours in 50/50 Simple Green and water. It will look like new afterwards, and simple green won't harm any plastic or rubber parts.