Float level adjustment

[TravEX]

86 250R

Need some help setting the float. I'm trying to follow the directions on pg 133 of the Clymer manual, but it's hard to understand what it means. "Hold the carb so the float arm is just touching the float needle, not pushing down on it. Use a ruler and measure from the carb body to the float. 16mm."

If I adjust it to where it's 16mm when the arm just touches the needle, it rides all the way to the top of the carb when it pushes down on the needle. This thing was leaking gas like crazy out the overflow tube. When I'm measuring I'm holding the carb at about a 100 degree angle.

Any help is appreciated.

[MTS]

Hold the carb sideways pretty much and watch the contact between the floatvalve and the needle, then mesure from the base of the carb to the top of the float(technicly bottem....when carb is right side up)

[TravEX]

thanks man

[Unclediezel]

You can hold the carb upside down, let the float rest on the needle- Float paralell to base gasket will usually get you in the" Park"

[TravEX]

so it shouldn't "bottom out" when the carb is upside down?

[Unclediezel]

No -The needle valve should hold it up--unless the needle tip is worn or the float "TAB" is seriously Bent

[MTS]

When the float height is set right to the 16mm the tab should just be touching the needle., when the carb is flipped upside down it should push the needle all the way back down into the seat.

[TeamGeek6]

86 250R

If I adjust it to where it's 16mm when the arm just touches the needle, it rides all the way to the top of the carb when it pushes down on the needle.

This thing was leaking gas like crazy out the overflow tube. When I'm measuring I'm holding the carb at about a 100 degree angle.

Any help is appreciated.

" it rides all the way to the top of the carb when it pushes down on the needle. "

Congrats, you just found the design flaw in that 86 flat slide PJ.

Hold the carb straight up, as it is when installed. Blow gently in a tube connected to the fuel line (no gasoline, of course) and hear the air come through the needle seat. Raise the float till it stops - thats the instant the needle touches the seat. That is the 16 mm point.

Set it there and itll probably still leak. Once youve set it, DONT change it, DONT bend the float arms and DONT change the float drop tang. If its gonna leak after that, its not a matter of float adjustment and like me, youll destroy the float trying to adjust it.

Take carb cleaner and compressed air (if you have it) and very carefully clean the fuel lines and carb. The tiniest bit of junk in the float needle will cause leakage. Remove the fuel shutoff by unscrewing the 2, 10 mm head screws in the bottom of the gas tank and inspect the fuel screen. Its probably hosed due to age. Thats enough to cause this problem. Make sure the tank is spotlessly clean and a new filter is a good idea.

You may find that nothing will fix it, thats how mine was (86R) because the float needle seat was defective.

A defective needle seat shows up as fuel rapidly filling the bowl until the float raises to shut off, then the bowl slowly continuing to fill. if that happens, inspect the needle end (rubber end) and look for damage. If its still springy and smooth, its probably good.

A bad needle seat means a new carb. I screwed with my PJ for a year off and on trying to fix this and it wasnt fixable, because the seat isnt replaceable.

I ended up eliminating the float altogether and it works flawlessly. Search for my post on it, its here somewhere.

[TravEX]

Thanks alot for your help. Going to try it now.

[TravEX]

Thanks TG6, that really helped me 'see' how it works and I got it adjusted as close as I could. The seat and the needle 'look' to be in great shape. I hate bending around on that tang expecting everything for it to snap off. Thanks again!

Trav

[TeamGeek6]

Good that youre making some progress. Avoid bending or distorting that float because it can bind the needle and cause BIG problems. I have a couple spare float needles if you need one. My old floats are wrecked though so they might not do you any good.

Speaking of... there might be a way to "fix" an old needle seat... hmmm... must think about it.:confused:

[TravEX]

Well, again, thanks for the help. If you make it to TF06, we'll have to meet up, the first rounds on me.

[TeamGeek6]

I C TF06 is at Haspin, that (was, anyway) an awesome place to ride. Have to try to make it if Im stil in the area.

[OldSchoolin86]

" it rides all the way to the top of the carb when it pushes down on the needle. "

Congrats, you just found the design flaw in that 86 flat slide PJ.

So if a carb is out of adjustment it's flawed?

[Jason Hall]

I'm sure there is a way to fix a bad needle seat in a keihin carb:wondering You just need a good machine shop guy. If there's a will there's a way:beer I would'nt let a little piece of brass beat me :D , especially with a rubber tipped needle like a pj carb has. A Mikuni with a steel needle in a brass seat is a little different.:cry:

[TeamGeek6]

I'm sure there is a way to fix a bad needle seat in a keihin carb:wondering You just need a good machine shop guy. If there's a will there's a way:beer I would'nt let a little piece of brass beat me :D , especially with a rubber tipped needle like a pj carb has. A Mikuni with a steel needle in a brass seat is a little different.:cry:

I didnt think mine would leak especially with a new rubber tip needle, but it did. The wear on the seat in my carb was visible, the edge of the seat where the needle lands was worn to a taper. I suppose a good machine shop could recut the seat and polish it, but a new carb is $120.00 and probably the same or less money as the machine work. Cutting a new seat with the brass pressed in where it is will raise the float level and its too high already.

That seat is a high precision part, I dont know whether just any machine shop could handle it without CNC and some kind of precision grinder. Keihin has a special division in Indiana that makes these precision parts, but Ive never seen their machinery.

I eliminated the whole schebang and now I can adjust the fuel level from outside the carb with the engine running:naughty:

[3leggeddog]

it's not a pj,it's a pwk,not thestock 86 carb.glad to see you got er adjusted

[TravEX]

the side is stamped "PJ" and I measured the opening, it's 34mm, I believe it's a stock carb, may be wrong?

[3leggeddog]

hmmm,i thought for sure it was a pwk,the guy at our local shop said it was aftermarket kehin,oops,sorry for the misleading info.did you get her fixed?

[TravEX]

yeah, waiting on my pilot jets and float bowl cap from Duncan racing for it to be completly done. Put a bigger main jet in (162), adjusted the needle and float, kicked over easy, adjusted the idle. Warmed her up and tried it out, much better, going to mess with it more tommorow when we go riding.

New question, is the slide supposed to be completly open in the carb opening when WOT? I adjusted it at the throttle and the top of the carbn to get the most possible travel (highest point) I could, but it still liked about 1/8" on the moon shaped side for the moon to be flush with the carb opening, and it liked quite a bit for the flat side to clear? Make sense? I don't know how to get any more travel out of it?

When it was all said and done, it runs alot better, starts easy with motor hot or cold, idles smooth. Just need my pilot jets to come in and that float cap so it doesn't leak any gas. Oh, TG6, no overflow, so the float looks good.

3leg, changed the oil today, and it's good!

[TeamGeek6]

It should come all the way up, but if the throttle cable is stretched, it might not. Theres an adjustment on the handlebar where the cable enters the thumb throttle assembly.

The PJ wont overflow until the fuel level is insanely high, about 1/4" over. Its only there to prevent fuel from running into the throat - no overflow doesnt necessarily mean teh float is right.

YEp, PJ34 is stock on a 250R, round slide on 85 and flat slide on 86 best I know.

[TravEX]

hmm, i'll have to work on getting that slide to open all the way up. The adjustment screw on top of the carb slips into a nut up in the casing of the cable, is it supposed to screw into there, is so , it's stripped, cause in just kinda pushes in there. I bet if that wasn't stripped, that would be the little extra adjustment i need.

[3leggeddog]

i thought the stock 86 carb was a 36mm flatslide?oh well,i hope you get the bugs worked out.the cable is brand new so that should not be stretched.maybe it needs the shorter 85 cable?i'm glad the oil is looking better,that means i did good changing that seal,woohoo

[TravEX]

i think the cable is fine, just that top adjustment is stripped.

have fun today on the X!!!

[3leggeddog]

well we aren't racing till tommorow.i really don't wanna ride her in the mud.i got another cap if you want it.no adjuster in it though

[TravEX]

I C TF06 is at Haspin, that (was, anyway) an awesome place to ride. Have to try to make it if Im stil in the area.

So, you gonna make it?