Float bowl screws/leaky carbs

prue1

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Hello everyone! My 72XS2 has two leaky original carbs. The float bowls are secured to the carb bodies by 4 screws per carb. Each carb has one screw that has stripped threads in the aluminum receiving carb body. This has caused a imperfect seal and therefore fuel leaking from the lower carb or float bowl. Does anyone have a recommended repair other then trying to locate/buy new carb bodies? I was thinking I might be able to use an epoxy/jb weld filler and drill them out and retap? Any ideas out there?

Thanks!
 
A pair of vise grips is what I usually reach for first before drilling. They sell smaller sizes that can grab the head of the screw. Make sure you soak it in some penetrate before attempting to loosen since it’s probably locked up.
 
Striped threads Bushy,
I have gotten away with using a machine screw with a little different threads, in that situation. You might only get one or two in and out with it but it grabbed enough to stop a tappet cover leak for me on two covers. Other wise heli coil or there is another similar product the name escapes me right now. But try a bit fatter screw or more aggressive thread screw for a quick temporary fix.

Also... Welcome, I'm sure you will be happy on this site an amazing wealth of knowledge and no question is to simple or plain.
 
Is there room above the float bowl to put a nut up there?
If so use a bolt the same diameter and thread long enough to go up through the body so a nut can be used. Hold the nut in place then thread the bolt up through.
Leo
 
This is not a structural repair so the JB-Weld fix might suffice. If not, I like the nut on top idea, done it may times but not in this particular application. If there is not room for the nut, grind or file one of the flats until it fits the space. This will also keep the nut from turning when you tighten the screw.
 
I've had luck using the longer screw and nut trick on two fuel bowels that some PO was rather ham fisted.....

tim
 
Thanks for the idea's guys. I have done the screw/nut combo on at least one where I have enough room. Currently I am using a machine screw, slightly larger/more aggressive thread in one, but I cannot get tight enough and It's a little mickey mouse. I hadn't thought of the helicoil Idea, I hadn't thought you could get one this small. Does anyone know where I can get the helicoils and what size I would need? Thanks.
 
BS38 bowl screws are M4's, the tops are M5's. On the BS34's, both bowl and top screws are M5's. There are many kits from different manufacturers available on Amazon. The Helicoil brand will be one of the more expensive ones.
 
I concur with Marty and 5Twins that the best way to make a repair like this is with a Helicoil thread insert. That will put a nice strong steel thread into the carb body in place of the margarine-grade threads in the soft aluminium. The result will actually be stronger than the original tapped aluminium part. However, Helicoils do require a bit of an investment, plus some skill to use.

I hadn't seen it before but given the company's reputation, I do like that Loctite product. Clearly, it is some sort of two-part epoxy and these modern adhesives have great properties. The real secret, IMO is the release agent on the bolt. I'd guess it is some sort of grease which doesn't interfere with the epoxy curing process.

Anyhow, lots of great ideas here to keep the old gals running.
 
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