Carb sealing

Discussion in 'Motorized Bicycle General Discussion' started by meowy84, Jun 18, 2010.

  1. meowy84

    meowy84 New Member

    Joined:
    Jul 18, 2009
    Messages:
    238
    Likes Received:
    0
    Assembling my engine and I already see that I'll probably need a way to seal the carb to the intake tube to avoid air leaks. Any suggestions?

    I know some of you have used silicone sealant but obviously that would have to be done on the outside of the tube/carb joint and I want to avoid the messy-silicone look. I know that some of the websites also sell an O-ring that's fuel resistant that seats on the little ridge in the carb entrance. I'm leaning towards ordering one but I hate to wait. So I checked my local plumbing shops and they have tons of the right size O-rings (3/4" diameter) but of course they're rubber and so not so good for fuel. Even if I use just a regular rubber O-ring and have to change it every couple of weeks when it degrades I could live with that. Any other options?

    What solutions have you guys used?
     
  2. charles.paskell

    charles.paskell New Member

    Joined:
    Feb 25, 2010
    Messages:
    201
    Likes Received:
    0
    I would steer clear of a permanent weld like application those rubber o rings sounds like the way to go also you could seal it with a couple wraps around it with electrical tape
     
  3. 2door

    2door Moderator
    Staff Member

    Joined:
    Sep 15, 2008
    Messages:
    16,308
    Likes Received:
    30
    I'm not a fan of the 'O' ring method. The rubber will swell and begin to deteriorate quickly. You don't want your engine injesting that stuff and it isn't a good seal because it cannot be clamped in except with hand pressure against the carburetor while installing it. Several members have also had the 'O' ring come loose and get sucked into the engine. Not good. Some suppliers offer a flat gasket, gasoline compatible, that will work better than standard rubber 'O' rings. I think you'll find that most silicone based sealants are not compatible with gasoline, (says so right on the package). There are some sealers that will do the job and if done correctly will not look like heck. When using a paste type sealant you want to fill the gaps (slots) where the throat of the carb attaches/clamps to the intake manifold as well as the entire surface of the intake where the carb goes.
    This product is a little harder to remove but I've had good luck with Seal-All. It is a clear semi-liquid sealant and will take gasoline. Good luck. Let us know how you do.
    Tom
     
  4. meowy84

    meowy84 New Member

    Joined:
    Jul 18, 2009
    Messages:
    238
    Likes Received:
    0
    Thanks for the input Tom. It did dawn on me that the O-ring or bits of it could get ingested so I thought I could make a little sleeve out of soda can aluminum to fit inside the intake tube and protrude ever so slightly beyond the end of the intake tube that should stop the O-ring from being ingested. The bend in the intake tube would stop the other end of the sleeve from trying to slide into the combustion chamber. Additionally the soda can aluminum is so thin that the effect on airflow should be virtually nil. As for silicone I was more leaning towards some of the auto gasket makers which have the consistency of silicone sealant (I should have been more precise) that are typically oil/fuel resistant but I remember most being red or blue which I wouldn't want to goop on the outside because of their looks.lI might try Seal All though as you suggested since it's fuel proof and clear in color so it won't be so noticeable.
     
  5. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

    Joined:
    Jan 8, 2008
    Messages:
    11,529
    Likes Received:
    3
    If you are having a problem getting the carb on enough to cover the "slots", I grind some of that end of the carb off with a belt sander.
     

Share This Page