Fuel leak

[Mopaw]

    I had a whiff of gas as I started my '99 Tourer this morning. When I got to my destination there was a strong smell of gas. Looked at the engine, there was gas running off the left side valve cover. Looked between #3 and #5 carb on the right side and saw gas dropping from above. Took it home (less than a mile), let it cool, pulled the tank. with todays heat most things were dry already, but saw a little wet on the T-fitting between 3&5 carbs.  I suspect a bad O-ring.
    If I pull the rear plate between the carb banks will #5 swing out far enough to change the o-rings?
    I will try to charge the fuel system with tank removed to verify where it is leaking.
    Anyone have other ideas?
Thanks,
Mopaw

[98valk]

tighten the end nuts of the two connecting rods that go through the carb banks holding them together.
they get loose overtime and allow connections btwn the carbs to leak. in 72k miles I've had to tighten them twice. it only took like a 1/16th of a turn.
the oem o-rings are Buna-N aka Nitrile and they can be different formulations. it seems honda used a formula for better chemical resistance but allows them not to be fast reacting to big temp changes. the last time, the one side leaked on mine was a big temp change in the winter time. did little turn on nuts leak stopped. 5k more miles and still zero leaks. I also put some clear silicone on the exposed threads.

highly unlikely they need to be pulled and rebuilt.

[Mopaw]

Yup, tightened the nuts, waiting for the weather to cool down enough to work outside. 106 degrees yesterday.

[The emperor has no clothes]

99% sure you need to remove the carb set and replace the fuel rail o-rings.

[rug_burn]

   Yeah:  I second that about pulling the carb carrier and replacing those fuel and vapor rail o-rings.  It's a time consuming pain in the butt; but that's the only way to fix it.   I've done it twice, and the cleaned the carbs and all jets, once.   An ultrasonic cleaner really helps  ($120 online.)
   Since you have to go to that far, you should replace all o-rings with viton units, check the diaphragms for holes, and in my case I replaced those rock-hard carb-to-intake tube rubber fittings (going down to the cyl head).  that makes the reassembly job a lot easier, too.

[WintrSol]

Less likely, but the leak I had, was the O-ring that seals the petcock to the tank, probably because it got knocked around over the years. Replaced the O-ring and put a drop of green Loctite on the threads, so it won't move unless I want it to.

[98valk]

Yup, tightened the nuts, waiting for the weather to cool down enough to work outside. 106 degrees yesterday.

did u move the T around fore to aft and up and down and then tighten?  worked for me twice and also a owner in my area. neither have leaked since.

[gordonv]

When you rode the bike, was this your first ride/start up of the year?

When sitting for a long time, the seals can dry out and shrink. They leak. After a while of running fuel through them again, the swell back up and seal.

I've never had this problem. Even after a few years of sitting.

[98valk]

When you rode the bike, was this your first ride/start up of the year?

When sitting for a long time, the seals can dry out and shrink. They leak. After a while of running fuel through them again, the swell back up and seal.

I've never had this problem. Even after a few years of sitting.

oem o-rings  are buna-n aka nitrile. they don't shrink, dry up and/or swell from fuel contact. unless left the sun and exposed to ozone, neither happens inside the carb body.