Help! My bike is hemmorhaging gas!!!



14 replies to this topic
  • Ridin'_MD

Posted January 18, 2004 - 05:35 PM

#1

Hey guys, I need your mechanical help. Took my '03 WR 450 to the track and noticed that the tube that drains the float bowl at the base of the carb was leaking gas. I tapped the carb a bit (thought the float was stuck) and it didn't stop. Did a few more laps and the leaking stopped. Few laps later and the leak was going again.

Went home and took apart the carb.... didn't see any problems. Took about a full can of contact cleaner to the inside of the carb (tried to get all the jets and clean the hell out of the float). I reassembled the carb and turned the gas on and gas now pours from that tube. What the hell?? :)
What is the deal. Does anyone know what the issue may be?

When I turn the gas off, the flow stops. It only flows from the tube at the base of the float bowl.

Thanks in advance for your help.

Bud :D

  • Indy_WR450

Posted January 18, 2004 - 05:45 PM

#2

That might be your drain bolt. Little 3 mm allen head bolt that locks the flow to the bottom of the carb float bowl drain line. :)

  • Ridin'_MD

Posted January 18, 2004 - 06:17 PM

#3

Meaning what? If I tighten this down, it won't leak?

I hate being clueless.

Bud

  • drzphatkid

Posted January 18, 2004 - 06:30 PM

#4

This happened to me one time.In my case i had just changed my main and pilot jets and when i put the bowl back on the little plastic splash guard that surrounds the main jet fell off and the float was stuck wide open. :)

  • Ridin'_MD

Posted January 18, 2004 - 07:05 PM

#5

OK took it back apart. When I blow into the gas line (into the carb, air still leaks in). This may be the problem, but what is the fix??

Also, what is this float needle that may have a nick....how do I check that?

Also, how do I remove the float to check where it is supposed to stop the gas in the upright postion and to see if it has a hole in it (don't think it does).

Thanks again, Bud :)

  • Ridin'_MD

Posted January 18, 2004 - 07:07 PM

#6

Also, Indy_450 (or anyone for that matter), if I crank down that allen screw, it may stop the flow but then would the gas that is supposed to drain just get in the engine??

Bud :)

  • gfergtr74

Posted January 18, 2004 - 07:25 PM

#7

Have you checked the float level? When reassembling it you may have bent the flange on the floats allowing too much fuel into the carb. The other possibilty is a bad float valve (needle). You should do a pressure test on the float valve. It should hold at least 5 psi. You can do this with a mighty vac or a pop off tester. Make sure to hold the carb upside down when doing this otherwise you will not get a correct reading.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • Gadsen

Posted January 18, 2004 - 07:36 PM

#8

Also, Indy_450 (or anyone for that matter), if I crank down that allen screw, it may stop the flow but then would the gas that is supposed to drain just get in the engine??


No, this overflow has two exits, one at the extreme top and the drain at the bottom. As long as the set screw is snugged down, the bottom drain is just for draining it or setting the float level only. Here is a picture to give you an idea

Posted Image


If there is debris in the needle and seat, you can turn the fuel off, run the engien till it starts to missfire, thsi will assure the float has dropped all the way down, leaving the needle/seat wide open, if some small piece of debris is in there, it will come out easier, now turn the fuel back on, this will usually wash it out. If not, it will require dissasembly. The picture is actually the way float level is set and its from a KLR650, but the same principle, though, the specs may be different, ie .5mm +/- 1mm etc.

  • Indy_WR450

Posted January 18, 2004 - 08:16 PM

#9

That drain should be shut when riding. It is only there to service the carb when you take it off the bike and dont want gas spilling all over the place. The bolt may have debris in it and cant shut the gas flow off. Clean it and tighten and you should not be able to blow air through the tube. The normal overflow lines and vents are the other hoses on the carb. :)

  • Machster

Posted January 18, 2004 - 08:19 PM

#10

I had the same problem.. I had changed the main jet, and somehow dislodged some tank plastic that was in the float bowl. You need to check it out with a fine tooth comb..I am sure this is the problem
Good luck!

  • John_H

Posted January 18, 2004 - 09:29 PM

#11

Just something to look for. I kept finding crud in my carby and finally found the plastic tube with the screen in the tank (on the petcock) had come off and was sucking gas without a filter. Fixed it, and put on an inline filter.

Also, may want to look for a slight groove on your float needle. Have had that problem too. :)

  • Ridin'_MD

Posted January 18, 2004 - 11:37 PM

#12

OK guys. I have messed with the screw in the picture and it seats well (seems to be working).

I think the problem may be with the float. If I manually push the float as high as possible up into the carb and blow on the tubing that carries fuel into the carb, I still hear the hiss of leaking air. When I let the float down the air flows unobstructed, but shouldn't there be a complete stoppage of air flow in the highest float position.

I mean isn't this how the thing is supposed to work? Gas fills the bowl causing the float to rise. It rises to the highest position completly stopping gas flow - right?

Questions......

1) Am I right about how this works and couldn't this cause the problem of overflow of gas into the carb and out the drain tube?

2) How do I remove the float to inspect it and inspect the valve which stops the inflow of gas into the carb (if there is such a thing). I think this may be the problem.

Thanks so much for all your help so far. I've got too much pride to take the bike to the shop!! I have to get it fixed by Wed. to go riding though :)

Thanks, Bud :D

  • gfergtr74

Posted January 19, 2004 - 10:37 AM

#13

OK guys. I have messed with the screw in the picture and it seats well (seems to be working).

I think the problem may be with the float. If I manually push the float as high as possible up into the carb and blow on the tubing that carries fuel into the carb, I still hear the hiss of leaking air. When I let the float down the air flows unobstructed, but shouldn't there be a complete stoppage of air flow in the highest float position.

I mean isn't this how the thing is supposed to work? Gas fills the bowl causing the float to rise. It rises to the highest position completly stopping gas flow - right?

Questions......

1) Am I right about how this works and couldn't this cause the problem of overflow of gas into the carb and out the drain tube?

2) How do I remove the float to inspect it and inspect the valve which stops the inflow of gas into the carb (if there is such a thing). I think this may be the problem.

Thanks so much for all your help so far. I've got too much pride to take the bike to the shop!! I have to get it fixed by Wed. to go riding though :)

Thanks, Bud :D


Yes you are correct about the fuel flow. There should be a small pin holding the floats in pace. Take the pin out and the floats come out. The floats opperate the needle valve which stops the fuel flow. I think they are a viton tip needle, meaning the tip of the needle will look like black rubber. Check for a ring around the tip of the needle. When these stop working usually there will be a vissible ring around the tip. Now look in the seat. The spot where the needle goes into. Look for any areas that seem more polished than other areas. Check for any debris that might be in there. Take the seat out and check underneath it. I am not sure if these seats have an oring or not but if it does it will be twards the bottom. This helps seal it into the body of the carb. Check to make sure that the oring is in good shape. I always use a very small amount of grease on the oring to help seal it when I reinstall it. Hope this helps.

  • Ridin'_MD

Posted January 19, 2004 - 11:12 AM

#14

HEY!!! I THINK THAT DID IT!!!! :D

I removed the float and took it out. The pin looked fine, but there was a small piece of plastic stuck in the opening that was keeping the pin from closing the hole!!!

I tracked that down to a small piece missing from the rubber o-ring in the petcock mechanism - go figure. How the hell did that happen??? Oh well.

I will reassemble the carb in a few hours to see if it works, but I am pretty sure that was the answer.

Thank you guys so much. As always, you are an invaluable resource. TT Rocks! :) :D

Bud :D

P.S. I will bump the thread if it doesn't work! Thanks again

  • Machster

Posted January 20, 2004 - 08:11 PM

#15

Just like I said!! I had that exact problem! Great work peeps! :)




 
x

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.