Can I permatex my float bowl gaskets?

[DogBunny]

I have a VB22A carbset on a 1981 CM400C.
It appears to be leaking from the float bowl gaskets. I carefully tried to find the leak source by pulling the carbs and then re-attaching the fuel source, so I'm pretty sure it is only the float bowl gaskets that are leaking.

Otherwise, the carbs are fine, so I don't want to buy a kit if I don't have to. I have not disturbed the gaskets. Can I fix the leak by applying Permatex on top of the existing gasket? If so, what should I use?
Is this a common problem?
Thanks...

[cb650]

Use a little Holamar.  I think thats how its spelled.   A little with the gasket and youll be fine.  Its very sticky and never dries.

[ExTex]

It is my understanding that the float bowls do not fill to the gasket level, unless the needle valves are not sealing.
So make sure that the needle valves are working.  I do not think you need a great seal on the gaskets.

Ride safely,

[DogBunny]

Thank you for the fast replies.
cb650, it is Hylomar, it looks good, I will try it.  Will report back.
ExTex, the needle valves look brand new, and the seats look good.  I think you are right about the fuel level being below the gasket, which is fine if the bike is on the centerstand, but the gaskets leak like sieves if I park it on the side stand or if I am in motion.

I find it kind of interesting that the float level is not adjustable on this carbset.  I have never seen a carb like that.  Maybe it's a good idea.  In any case, the float level is correct.

[muttstang]

fuel will eat through permatex.  Your best bet is to try to find the proper gaskets.

check here:

http://www.newmotorcycleparts.com/fuel_system_parts/bowl_gaskets.html

[muttstang]

call them to order if you want them to ship it in an envelope so you can get a bit cheaper shipping

[jerjohn]

The p.o. of my 450 put permatex on the bowls instead of replacing the needles. Eventually my left carb began to drip when parked, then drizzle a bit, then pour out all the time while parked and moving. The rubber on my needles also looked good and the seats (which are not removable) looked fine. After assembling the carbs twice with new gasksets and still having leaks I ordered new needles. I installed the needles valves and polished the seats with a metal polish coated qtip in a cordless drill.

Save yourself the headache and frustration I went through and order some new valves and float bowl gaskets. I am a pennytech guy on some repairs but believe me its worth the money to just order the parts 

cheers

[DogBunny]

Again, thanks for the fast responses.
muttstang, excellent find. 
jerjohn, I think you meant to say that the PO put permatex on the bowls instead of replacing the GASKETS.  In any case, you have convinced me to do the right thing.

I really would have liked to see what the Hylomar would have done, as it is supposed to be fuel resistant, but who knows when the gas has ethanol in it?  Also, I am selling this bike, this is all it needs, and I guess I can spring for two $6.50 gaskets.  Will report back.

[cb650]

I used it on a set of carbs 15 years ago and its still tacky.   Dont leak.  Never have bought bowl gaskets.

[DogBunny]

Well, now you're making me feel bad for not trying it...
Thanks again, this is great Forum.

[jerjohn]

Yea, I didnt mean he put permatex on instead of gaskets. He put it on top of the gaskets and closed the bowels with out fixing the root problem. The permatex stopped the gas from leaking out of the carb but it didnt prevent the bowls from overflowing. By sealing the symptom and not addressing the problem all the PO did was guarantee that the carbs would be flooding and letting gas seep through the intake, past the rings, and into the oil.

Since the carb bowl is leaking a lot while the bike is in motion that may indicate that a your needle valve is not seating and flooding the carb. Since you will have the carbs off and opened up, why not replace the needles and clean up the carbs?

"Cleaned carbs and replaced float valves" sounds a lot better than "fixed carb leak" in a for sale ad. Good luck

[cb650]

Ok "permatex" is a brand name that makes several products.  Hylomar is one of them.  no I wouldn't use their silicon based  product on a carb.  Yes maybe you need to replace a needle valve.  That being said in the real world your bike should be subject to turns bumps and vibtations.  That might slosh the fuel around some and leak at the bowl.

[jerjohn]

Mine had the red high temp rtv silicone sealant on it.  Im gonna get some of the hylomar for my tool kit. From the permatex site on usages,
"Thermostat housings, differential coverings, hydraulic drives and motors, gearbox assemblies, intake manifold assemblies, oil, fuel and water pump housings and seals, fuel injectors and fuel pumps, transmission and torque converter seals" Sounds like a good product to have.

[DogBunny]

I fixed my leaking float bowl gaskets.  I bought a pair of gaskets on eBay for $12, including shipping.  I am thankful that the gaskets really were the source of my problem, and that it was such a cheap and easy fix.

I have to say that I think the gasket design is weak on these old carbs, but I guess that isn't news.  Thanks to everyone who responded to my post.

[Bumblebee]

I have to say that I think the gasket design is weak on these old carbs, but I guess that isn't news.

Any kind of rubber gasket is going to be ready to fail in 25 years. It's an inherent problem with rubber.

If you look at vehicles in general, they're expected to stay on the road about 10 years before the owners replace them with something newer. I wonder if the CB series designers realize they outdid themselves with something that goes 30 years and is still running nearly like new.

[mikefootusa]

Is there a need for any kind of gskt sealer if you have new gaskets?  PO had used something and the old gaskets were stuck in there pretty good...and not pretty...lol.  Ready to reassemble...got my gskt set and float needles yesterday.  The vacuum slides had some wear on them...should I buff them up a bit with 3M pad?

[gammer]

The vacuum slides had some wear on them...should I buff them up a bit with 3M pad?

This is normal. Just leave them as is.

[mikefootusa]

What about the gskt sealer with new gaskets?

Also, during my search for parts and info I came across this:

http://www.hondanighthawks.net/82_450_CarbSB.pdf

thought someone else may come to find it useful.

[mikefootusa]

Pulled the air cut-off diaphram from carb #1 yesterday...junk...will that necessarily mean that 2,3 and 4 are the same?  Anyone find these cheaper than $24/ea?

After hours of searching found these as a set of four (4) for $42 including shipping:
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=290611134815&ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649