Carb leaking

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vmax1998

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Hi on the left side of my 98 vmax it seems like the carb is leaking. I recently synced the carbs to the best of my ability and went around to all the carbs and made sure the af mix screws were all 2.5 turns out. My back left carb on the left side is wet around the outside and it smells like fuel. I was wondering what might be causing this. Maybe I could get a picture later. The bike has supertrapps with 7 discs and a drop in k and n filter. Other than that it is stock. Also seems to run really well in the midrange but coming right off of idle it seems to not have the same instant response. It’s a little laggy. And on the top end it seems to have lost some power.... I’m not a carb expert I’m more knowledgeable about fuel injection so maybe someone might know where I can start with tuning?


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How much fuel are you talking about?

Could be a stuck float. Thats usually a lot of fuel coming out the airbox hose.

Could be leaking past the float bowl drain screw. Id drain all the float bowls individually into a glass container and mark the container with the fuel level in each as a comparison. Its good to know if one us way out of whack.

While you drain them, you can polish the tips of the screws that seal the flat chamber. Polish the seats too. Check the o-rings.

Check to see if diaphragm screws are tight.


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How much fuel are you talking about?

Could be a stuck float. Thats usually a lot of fuel coming out the airbox hose.

Could be leaking past the float bowl drain screw. Id drain all the float bowls individually into a glass container and mark the container with the fuel level in each as a comparison. Its good to know if one us way out of whack.

While you drain them, you can polish the tips of the screws that seal the flat chamber. Polish the seats too. Check the o-rings.

Check to see if diaphragm screws are tight.


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It’s just enough fuel to make the carb visibly wet unlike the others and it smells like fuel all the time. I’m not too familiar with carbs as I am 21 years old I know how they work but haven’t taken one apart before. I did a Barnett clutch replacement on my vmax and brakes and stuff so I’m mechanically inclined. Thanks for your input I’ll have to take a look at it this weekend as the bike is my daily.


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The design of the carb drain screw is such that it will leak even if closed if the o-ring is bad.
 
The design of the carb drain screw is such that it will leak even if closed if the o-ring is bad.
Been there, done that, had leaks and smells from two carbs one on each side, replaced orings and tada problem solved:eusa_dance:
 
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I'm having this issue also. Does someone know the size of the wrench needed to remove the drain screw?
 
I'm having this issue also. Does someone know the size of the wrench needed to remove the drain screw?

3/16" slot head screwdriver or a #2 phillips screwdriver

Vmax carb drain screw.jpg
 
Last edited:
Thanks Fire-Medic, The drain bolt I'm looking at is the one that has an o-ring. It's located on the bottom of the cover of the float. Hope you're keeping safe and healthy in FL.
 
Thanks Fire-Medic, The drain bolt I'm looking at is the one that has an o-ring. It's located on the bottom of the cover of the float. Hope you're keeping safe and healthy in FL.
10 mm main jet access bolt
 
Just arrived, a bunch of OM carburetor parts to finish a re-build on a set of Gen 1 carburetors. Gaskets, jets, plugs. Eats-up $150 in a hurry. Thank god the diaphragms/slides are OK.

VMax jet block clean-up.01.jpgVMax jet block clean-up.02.jpgVMax pilot jet drill-out.01.jpgVMax pilot jet drill-out.02.jpg
 

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