Bad o-rings on pilot-screws

MFolks wrote: You'd think somebody here will have the parts you need:

Carb Parts
www.nrp-carbs.com
www.carbkitscapital.com
www.pjmotorsports.com/carb-rebuild-kits.html
www.mikuni.com/fs-carburetor.html
www.jetsrus.com
www.carbparts.com
www.oldbikebarn.com/Motorcycle_Parts/Carb-Rebuild-Kit
www.siriusconinc.com/


And if no luck, try www.z1enterprises.com

From personal experience if you are in a hurry or good customer service I would not use Carbkitcapital unless I absolutely had to. I waited 3 weeks before I called someone just to find out they do not actually stock anything.

Bunty27 wrote: And on that same note, I may have to replace the o-rings on my drain screws too.

I notice that fuel's leaking out of overflow tube on one of the carbs. I adjusted the fuel level and it seemed to be ok but I'm not really sure. Could it just be the o-ring or something else?

And if it is the o-ring, can you please point me to an ebay link again? I tried looking but was unable to find anything.

There are two orings on the drain screw. The tiny one is what seals when the screw is all the way in. The large one is just to prevent leakage of air and/or fuel around the screw while draining the carbs or setting the fuel level.

If the little one leaks, it will drip all the time. If the large one leaks, it will only drip while draining or setting fuel level (using the clear tube method).

Neither oring will stop the flow if the real problem is the fuel level being too high. It s designed to let the fuel out if the floats are letting in too much.

Very very rarely, you can develop a leak even when the fuel level is set just right and the float valve is working perfectly. This happens because the brass overflow tube develops a crack, or is not sealed into the bowl casting. This is very rare.

Most often, the cause of leaking from overflow tubes is the float valves leaking. Look at the float needles. If there is a visible wear groove around the tip, then the needle is history. It's normal for there to be a slightly polished ring, but it should not be a groove. Once it's a full groove, the needle will sometimes seal, and sometimes leak.

If you do get new float valves, you will have to reset the float height. You do that with the clear tube method described in the manual, but you can get them in the ball park if you check the maintenance page on my TK22 website.

After spending some time this morning looking again, I noticed that the petcock valve(on the tank) had developed a leak and the fuel was leaking even when the switch was not in the PRI position. I soon realized that the one of the plates on the valve had actually rotated which caused the leak and once I put it back it place, the leaking stopped. I plan on doing a maintenance on this valve soon.

Now back to the leaking carb issue. I just replaced all 4 float valve assemblies with the new ones I got from z1enterprises. When I was installing them, I noticed that the springs on one of the float valves didn't seem to be as strong as the other three. By this, what I mean is that after installed the float valve assembly and the float, when I'd tap on the float(against the valve, upside down)), the float would actually almost bounce a couple of times before stopping on all 3 carbs except one. I moved around that float valve assembly between the carbs and the problem moved. To play it safe, I installed this valve on one of the far-end carb and sure enough, this is the one that has the leak. My best guess is that the float valve is not closing all the way and is not plugging the fuel flow. I tried adjusting the float tang to set a lower fuel level and that didn't seem to help. When I did the fuel level test yesterday with a clear tube, the level was a bit lower than the other carbs (not much though). I'll also inspect the lower o-ring again today to see if there is a problem there.

Thanks to all of you for taking the time to explain this stuff to me. I'll keep you posted.

Thanks for posting that. It doesn't sound good. Try moving that float valve to another carb to see if it will seal for you. If it doesn't contact Z1, I'm sure they will fix this for you.
Aren't carbs FUN!!! :whistle: :silly:

Bunty27 wrote: ...back to the leaking carb issue...My best guess is that the float valve is not closing all the way and is not plugging the fuel flow...When I did the fuel level test yesterday with a clear tube, the level was a bit lower than the other carbs (not much though)....

The float valve must be functioning correctly -- not leaking -- when performing the clear tube test.

A leaking float valve invalidates the clear tube test, because the fuel level keeps rising above the correct level, until escaping through the overflow circuit.

Where fuel is escaping through the overflow, the fuel level is already too high.

The clear tube test relies on the float valve to stop fuel flow into the carb float bowl, at which point the clear tube test reveals the fuel level, which level must remain stable throughout the test and not be changing due to a leaking float valve.

Good Fortune!

I verified this evening that the float valve is working fine and is able to stop the fuel flow when the float presses against the float valve spring. It looks like I had a bad O-ring at the tip of the float bowl screw. This seems to have allowed the leak to have happened.

Anyways, I have the carbs out again and I plan to inspect all o-rings, do float checks,inspect and clean all jets, verify carb valve heights etc. etc. before I install them back again.

Thanks much for all your help and time in getting this resolved.

I cleaned up all the valves in the carbs, adjusted the fuel levels, set the air screws correctly and re-installed the carbs back on the bike with the air ducts and air box installed correctly. And viola, everything sounds so much better and the bike's running very well. Thanks for all your help again. For those who haven't seen my bike yet, here's the link:

kzrider.com/forum/11-projects/549241-int...y-first-project-ever