OMG Carbs STILL leaking gas

[Chrondor]

Hello,
I am having a nagging drip from my carb that just won't go away.
Cleaned carbs thoroughly and changed valve needle seat along with 24mm float height.
What am I missing here?
1973 TX650
Gas was coming out of overflow but is now seeping out of bowl and dripping off the flat plate facing the engine.
I have tightened the s*** outta the bowl screws & don't want to strip them.
Any topical advice is appreciated.
Thanks- Chrondor

 

[ThatXS650Guy]

Petcock? I've had problems with getting Yamaha petcocks to stop weeping. My Kawasaki petcocks don't leak at all.
I would suggest setting the float heights via the clear tube method. Dry float heights are just a starting point. It's fuel level that is important.

 

[5twins]

Aftermarket float needles and seats? Many of those are junk right out of the wrapper. Originals are still available and even though they may cost a few dollars more, they're worth it .....

http://www.boats.net/parts/detail/yamaha/Y-168-14190-20-00.html

 

[Chrondor]

I actually got those "boats.net" valve seats after it became obvious the ones I bought were junk.
Is it possible my floats are "hanging up" somehow?
The fuel should be getting cut off and yet it is perpetually leaking in the most annoying ways.

 

[5twins]

I suppose it's possible. The float may have gone bad too, started leaking and taking on fuel. That makes them heavier and they don't float on top of the fuel level like they should, they sit lower in the gas. That makes the bowls fill more before shutting the float valve off. I think you need to give them a good inspection. Remove them and shake them to see if there's any gas in them. Submerge them in a cup of hot water and watch for bubbles coming out.

 

[grizld1]

It's rare, but leaks can occur where the brass standpipe that vents the float bowl is pressed into the float bowl bottom. When that happens fuel leaks from the vent barb on the bottom of the float bowl as if fuel level was too high or the float or float valve had failed. I tried sweating solder into a bad standpipe joint once, and that attempt was a fail. The only sure fix I know of is replacement.

 

[TwoManyXS1Bs]

Both of my XS1B's float bowl overflow tubes were split and leaking. After 2.5 years, this fix is still holding.

http://www.xs650.com/media/71xs1b-carbs-overflow01-attach-a-hose-to-the-bowls-overflow-barb.23289/

http://www.xs650.com/media/71xs1b-c...e-blow-into-the-hose-watch-for-bubbles.23290/

http://www.xs650.com/media/71xs1b-c...tubes-but-from-vertical-splits-as-well.23291/

http://www.xs650.com/media/71xs1b-c...long-these-sleeves-will-repair-the-ove.23292/

http://www.xs650.com/media/71xs1b-c...-epoxy-and-slid-down-onto-the-overflow.23293/

 

[Wingedwheel]

If everything inside the carb checks out I would agree with ThatXS650Guy. I kept noticing fuel leaking and it turned out to be the petcock, replaced it and issue disappeared.

 

[grizld1]

I like it, 2M! The covering tube also gives more area at the base for the epoxy to adhere to. Original formula JB Weld?

 

[TwoManyXS1Bs]

Original formula JB Weld?

Yessir, the good stuff...

 

[5twins]

I repaired one of my petcocks with it maybe 6 to 8 years ago and it's still holding up fine.

 

[gggGary]

Overtightening the bowl screws is a problem creator. The bowls are soft enough to easily bend up at the corners from too much screw pressure Twomany details his travails with bent bowls. He mentions VERY carefully working them back to straight. Think I've done that at least once or twice.

 

[5twins]

I should also mention that when you set/check the floats by measuring, you should check both sides of each float, measure each float "bulb". Many times they are tweaked or twisted and one side will sit higher or lower than the other. If you don't measure from both sides, you won't catch this. If they are twisted, the fuel level you think you set may not be what you're actually going to get. This is a pretty common occurrence. Probably near half the floats I check are tweaked some. Even new ones can be. These brass floats are a pretty fragile assembly, easily bent or twisted.