Do these carbs bowls just weep gas?

[Juan1]

These are my data points leading to this question.

On my old '89 GS500:
1. I personally rebuilt the carbs, installed fresh gaskets, checked to make sure the needle valves and seats were stilll in great condition, the floats were in spec, and all vacuum lines were clear. It still wept gas, although less of it (likely due to the fresh gasket). 
2. Assuming my lack of experience resulted in me making a mistake in #1, I took the bike to a shop.  The shop said everything was OK, though they did rejet the bike for me.
3. I took the bike to ANOTHER shop that I trust more.  They took everything apart, said the carbs looked fine, and their best explanation was that the float bowls are held on by two, rather than the four bolts, which eventually leads to the bowls not being held on tightly enough where the bolts are missing.

My new '98 GS500.
1.  I just bought this at the beginning of the month.  Guess what?  It leaks a bit of fuel from around the float bowls, particularly on the sidestand side.
2.  Now that I have worked on several carbs (GS and otherwise), I have more confidence in my analysis.  I took the carbs off last weekend, and know that the float bowl gasket looks good, and the needle valves as well as the seats look nearly new.

Do GS500 carbs just leak when left on the sidestand and the petcock in the ON position?  If not, what am I missing?  My other carbed bikes haven't had this problem.

[Funderb]

That is an interesting problem, I've never had a carb leak fuel for reasons other than a faulty gasket.
My 98 doesn't have a fuel leak, and oil leak, sure, but its air-cooled, i'm okay with it.

Check the gasket carefully for rolls or cracks, if a gasket rolls, it will look serviceable, like it should seal, but when you torque it it sits funny and leaks. My valve cover gasket is doing that right now, as I type.

One thing I did change, the bowls were held on by crappy, soft, 'brite' machine screws with phillip's head drive, i changed them all to powdercoated allen key drive screws, they dont strip out easily, and you can torque the bowls on nice and tight. (not too tight)

oh! it just occurred to me: Tightening sequence: if the screws are tightened one at a time, not evenly, the bowl will warp, and will may never seal properly again, or may be remedied by re-tightening the bowls evenly. (Like the way you would put the valve cover on.)

Leaking fuel is bad, i hope you can remedy this!

[Dizzledan]

It could be the previous owner tried to get the bowls off with a screwdriver after he stripped out the JIS screw heads that come stock.

A more realistic scenario, is you have a sticking float and you're seeing gas leak out of the carbs with no-where else to go.

[Kijona]

Mine did that after the 3rd time of re-using the carb bowl gasket. Please replace your JIS screws with cap-head-bolts, preferably of the stainless steel variety. That way you can easily and safely tighten the bowls down AND you don't have to worry about stripping the head off - just gotta be careful you don't over-tighten it.

[twinrat]

juan you may have a warped bowl,do a test get a bit of flat glass and put some emery paste on it then put your bowl on it and move bowl in a figure 8 motion for about 30 seconds then clean bowl and look for even contact marks across the face of it.If its not even you will have to do it again till you have contact across it ,this is called lapping .you could also put felt pen on the bowl face also just to check it .

[piresito]

Also, the bowls can be switched, the left one on the right carb and vice versa.
On solution could be that universal gasket sealant silicone that I personally hate, but might work for you.

[BaltimoreGS]

Also, the bowls can be switched, the left one on the right carb and vice versa.
On solution could be that universal gasket sealant silicone that I personally hate, but might work for you.

A lot of silicone sealers will not hold up to direct contact with gasoline.

-Jessie

[piresito]

Yeah, you got that problem either. Altough in my case the silicone was there for 6 months and no single drop of fuel leaked, it holded pretty well.
See this:

http://gstwins.com/gsboard/index.php?topic=58875.msg670260#msg670260

A problem with that is that some of it might go into the bowl messing with the carbs function. But if there is no other way to stop the leak, it worth's a try.

[Kijona]

This may work:
http://www.permatex.com/products/Automotive/automotive_gasketing/specialty_gasket_maker/MotoSeal_1_Ultimate_Gasket_Maker_Grey.htm

I don't know for certain though - it does say it specifically resists gasoline.

Here's another:
http://www.permatex.com/products/Automotive/automotive_gasketing/gasket_sealants/auto_Permatex_Hylomar_Universal_Blue_Racing_Formula_Gasket_Dressing_Flange_Sealant.htm

Even says under recommended uses "fuel pump."

Good luck dude!

[Juan1]

Thanks for the tips guys.  I boiled the carbs and put them back together.  The sidestand-side float was 1mm above spec.  If the problem persists I'll order a new float bowl gasket (this one is intact, though definitely harder than new).  If the problem still persists I'll take the silicone option.

If leaks are unusual, my old GS500 probably did have a warped bowl.