CBR 600F3 1995 - 1998 CBR 600F3 Forum

Need help with gas leak

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Old 03-20-2010, 09:31 PM
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Default Need help with gas leak

Today was finally above 50 degree's so I decided to start my bike for the first time since storing it last fall. It started up ok, but shortly after I noticed gas leaking on the driveway. I figure I left one of the screws open from draining the carbs last fall. That wasn't it. I tore everything down and got a closer look at the leak. I know this is vague, but it seems to be coming from beneath carb #4. (See pic #1) Now that I'm this close to the leak, I'm not sure what to take a part next, and not really sure what I'm looking for? Anyone have any suggestions where this could be leaking? Sorry this is kind of vague, but that is about all the info I can give right now. Also, when taking the air filter off, I noticed an oily gas substance, on each carb. (See pic #2) I wouldn't think that should be there. It is on all four carbs.

Sorry for the long post. Just wanted to give details. Thanks in advance for any information anyone might have as to my next move. I'm at a loss....btw it's a 97 CBR
 
Attached Thumbnails Need help with gas leak-general-area-leak-1.jpg   Need help with gas leak-oily-gas-carb-2.jpg  
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Old 03-20-2010, 09:45 PM
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It might be the float bowl gasket that needs replacing, it's an old bike.
 
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Old 03-20-2010, 09:52 PM
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Given where you're pointing in pic #1 and assuming there's no gas directly below the float bowl cover, I'd guess the o-ring on the breather tube to the #4 carb has let go

http://fiche.ronayers.com/Index.cfm/...Y_-_F3_-_95-96

Part #10 in the gasket set.
 
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Old 03-21-2010, 08:57 AM
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Thanks for the quick replies. I'm always amazed how helpful people are here.

The gas is definitely coming form above the float bowl, so I will check out the two things mentioned above (float bowl gasket and o-ring on breather tube.) I assume it will be obvious if I inspect these items as to whether they are the culprits or not?

Also...should I be concerned about the oil/gas shown in pic #2.
 
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Old 03-21-2010, 09:14 AM
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Well since you say it's coming from above the float bowl, I'd not worry about the o-ring till you try the gasket. The o-ring I'm talking about will require you to completely disassemble the carbs.

Hard to say if pic 2 is an issue or not. Can't tell if its an old deposit or something fresh. I'd take a cloth with some degreaser on it, clean it off and then put everything back together. Check it after a week or so to see if it came back
 
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Old 03-21-2010, 09:28 AM
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The "O" rings on the fittings between the carburetors are getting old and brittle. If you look in the photo below, the light blue arrows indicate where air travels through, the dark blue arrows are where water flows through, and the red arrow is where the fuel supply is.

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Your fuel line T looks like this. You can see that the "O" rings are pretty encrusted with years of use.
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Even after cleaning, they still look really bad and pitted. The pits are what let the fuel leak out.
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If you look at the microfiche above you'll see that you have several choices for purchasing "O" rings and such, but it's hard to tell what you get. Well, here's what you get depending on the part number you choose. The upper package includes the "T" fuel tube, which you don't need. This item is around $20 and you'd need 2 of them. There is nothing wrong with the "T" fitting, just the "O" rings. The bottom package sells for about $7.50 and contains 2 different "O" ring sets. One of the light blue arrows points to a white "T" fitting and the red arrow is to the fuel "T". Since you'll have your carbs this far apart, you're going to want to order 2 of these packages (the bottom one).
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Here's what you get for that package.
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Make sure you clean out the openings real good before putting back together, otherwise it will still leak. I use a piece of ScotchBrite pad on the end of a small screwdriver and spin it around in the openings.
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For the oily stuff, you're going to need some carburetor cleaner in a spray can. Get a couple of cans so you can use is liberally without the worry of running out. The spray is hard on "O" rings and plastics, so remove those thigns before going to town on the carb bodys.

Good luck and let us know if you've got any other questions.
 
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Old 03-21-2010, 09:43 AM
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Gotta love IDoDirt. He makes everything better with pictures

The orings on the fuel T junction were the ones I was talking about. From the pics posted of the #4 float bowl gasket, it looks ok. Hard to tell since it wasn't the focus of the pic. But it looked like it still had roundness to it and extended above the lip of the float bowls.

O rings are funny things. Had an oil leak at the water pump cause of one. Pretty bad one and the oring looked fine when I pulled it off. But a new one fixed it just fine
 
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Old 03-21-2010, 10:07 AM
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Originally Posted by Kuroshio
From the pics posted of the #4 float bowl gasket, it looks ok. Hard to tell since it wasn't the focus of the pic. But it looked like it still had roundness to it and extended above the lip of the float bowls.
I think you might be a little confused on what you're looking at. The gaskets in his photo's are where the velocity stacks and the base of the air cleaner box go. Those rarely go bad unless they've had carb cleaner sprayed on them. No big deal though, easy mistake.
 
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Old 03-21-2010, 10:22 AM
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Originally Posted by IDoDirt
I think you might be a little confused on what you're looking at. The gaskets in his photo's are where the velocity stacks and the base of the air cleaner box go. Those rarely go bad unless they've had carb cleaner sprayed on them. No big deal though, easy mistake.
yup, my bad. Not enough coffee yet. Love my girlfriend but she just can't seem to remember to fill the coffeemaker for the mornings
 
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Old 03-21-2010, 11:33 AM
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I belong to a few other forums for cars and such, and I'll say it again..this is by far the most helpful and friendly forum. The fact that someone will give detailed info and post pictures is amazing! Thanks IDODirt! Sounds like you have dealt with this before.

In the next few days of my hectic life, I hope to look at those o-rings. Update to come!
Thanks again.
 


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