I drained the carb bowl this spring to get the bike started - worked like a charm. But now it's leaking through the carb bowl drain. I've noticed that there is only a small noticeable leak on significant downgrades.

I have pulled the drain screw out all the way and opened the petcock to flush anything out. I put the screw back in all the way and still slowly leaking fuel. I've checked the screw tightness and am worried that if I tighten anymore I will strip the screw head.

Any thoughts?

 

That's odd since there's no o-ring or anything much to leak. There must be something like grit or a sliver of metal or such wedged in the seating surface between the screw and carb bowl. Maybe you could get a small brass brush like a very small caliber gun bore brush...maybe .17 caliber...and work over the carb bowl hole with it. You could use a regular brass brush to scrub the tip of the screw in hopes of dislodging a crushed object or substance embedded in it.

The only other thing I can think of is that there's something not allowing the screw and carb bowl threads to fully seat.

 

RB & TNC, you're both sure there's not any kind of plastic, brass or copper washer, or o-ring, meant to go there? I don't recal what the KLX's is like myself, but other carbs i have worked on definitely do...It's a CVK 34?
Perhaps the screw is damaged(?). Try looking through a loupe under bright light.
RB, if you can't resolve the leak with a cleaning, and no washer is missing, you might try a little teflon tape. Be careful not to allow any little bits of it into the float bowl itself though; there's a risk of clogging a jet that way.

 

Nope, there is no sealing medium like an o-ring or washer. It's like a metal-to-metal pipe fitting kind of seal. I just pulled mine out to check it, as it's sitting on the shelf. I'm still thinking about a possible cross-threading problem. If anything is upsetting that perfect metal-to-metal blunt tip into blunt hole, fuel is going to dribble out.

 

There's no cross threading issue and its only leaking down the drain tube, not out the screw. I haven't been able to look at it again. Still, weird that it doesn't leak while stitting or when riding on level ground.

 

Get some Teflon tape that gas resistant.....easy fix

 

Oh...that's a whole other issue. That sounds like a fuel level issue.

 

I concur! LOL

A float needle/seat issue or the float fuel logged or not adjusted correctly.

Welcome to KF RB if I have not already.

 

Thanks Dragone and TNC.

I'm gonna be attempting a re jet in a week or two when I get a slip on. I dont know much about carbs but i want to learn by doing this stuff myself. What's this fuel level/float needle thing I need to look at?

 

Setting the fuel level is best done by using the clear tube method. It's similar to the factory method described in the shop manual, but it doesn't really require their special tool. All you need is to get some fuel resistant hose...like chainsaw fuel line...that fits the fuel drain nipple that the black OEM drain hose attaches to. You get a length of hose long enough to attach to the bowl drain nipple and bend it without kinking it to the side of the carb bowl and carb body line. Follow the directions in the shop manual and check the real fuel level that's in the carb rather than just the static height of the float. I've seen many times where the float's buoyancy characteristics aren't just perfect, so the static height measurement of the float as it rests against the needle isn't always an exact science. Plus, using the clear tube fuel level method allows you to know for sure what the real fuel is, and it eliminates any issue with a needle/seat, sticky float pin, or imperfect float.