I was trying to extract on of the screws that attaches one of the float bowl covers, but I messed up the thread really bad, and now I can't get a screw in there. Someone mentioned that I could put some epoxy around the hole and just put the screw back in, and it should cure. I'm not too sure about this as I've never used epoxy before. The hole is pretty gounged. I don't know what I was thinking 

Quote from: rock_rebel on August 22, 2011, 05:17:55 PM
I was trying to extract on of the screws that attaches one of the float bowl covers, but I messed up the thread really bad, and now I can't get a screw in there. Someone mentioned that I could put some epoxy around the hole and just put the screw back in, and it should cure. I'm not too sure about this as I've never used epoxy before. The hole is pretty gouged. I don't know what I was thinking 

I have never heard the epoxy trick before, my thinking on that is what will do you if you have to take the float bowls off again?  What I would look into is buying a tap and trying to repair the threads, that would be the best fix.  Just be careful to clean everything in the carb after doing that, you would not want metal shavings / flakes to end up in the combustion chamber. 

Depending on how bad, a thread restorer tap with some grease on it might work.  Otherwise you're gonna have to drill it and tap new threads. 

As an alternative, you could simply fill the hole with JB-Weld; be sure to get the surface as smooth and level as possible before the JB-Weld hardens. Then drill a SMALL pilot hole, then one almost as large as you need, then finish by tapping the hole to the proper size.

JB-Weld is GREAT stuff; you can drill/cut/file/sand it without a problem. It is certainly strong enough to repair that hole with; the threads won't be under a lot of tension, so as long as you allow it enough time to cure properly, it will probably outlast the rest of the motorcycle.

You could also take good notes and photos, then document how to do it for others who have a similar problem in the future... just a hint...

nvm misread thread

http://tds.loctite.com/tds5/docs/FORMSTRK-EN.PDF

Not a very good pic but it will give you an idea of how far gone the screw hole is:



Tried to re-thread but it just made the hole worse. I think I might bring it to a machine shop tomorrow that might  be able to re-thread a new hole.

If all else fails, maybe one of you guys have a carb lying around that I could get parts from 

As you can see the screw isn't really essential as it just holds the bracket.

I'd argue any screw is essential in a system like a carburetor.

Have you looked at heli-coils? I've never tried them, but they might work for you. I didn't do much reading on their heat rating though.

Ideal application for a thread insert. Quick and easy and dont worry about heat, if they can hold spark plugs in they will cope with that bracket. Take it to shop and see what they say.............or..............

If you are in a bodging mood find a suiitable fastener, cut the head off it, glue it into the hole with Araldite and use a nut/washer to hold the bracket onto it.

I decided to give the epoxy idea a shot and picked up a tube at my next door auto parts store for around $6:



The epoxy works at a maximum temperature of 250C (482F for you US folk). At first I wasn't sure if it was good enough to withstand the carb heat at operating temp, but I will give it a try anyway. I took a small piece of epoxy with my finger and filled the screw hole. Then I attached the bracket and stuck the original screw in there. The screw didn't insert all the way so I put some additional epoxy around the area of the screw and bracket. After waiting an hour for the epoxy to cure this was the end result:



The epoxy is pretty solid. I put a decent amount of pressure on the repaired area and the screw didn't move. I hope it stays that way.

Thanks to many for your help and ideas!

Hey man, it looks like a good fix to me... Of course, now that you've epoxied the screw into place, you'll probably never be able to get it out again, but that might not matter to you. If the repair suits your needs, then it works for me as well... not that my opinion counts for anything here, just sayin'...

I've actually used Tech Steel a few times; seems like a good product, and it worked for my needs. As I previously mentioned, I've also used JB-Weld (and JB-KwikWeld), I prefer JB-Weld for most jobs because I can mix it to set-up slowly, then add catalyst (hardener) to it when I'm dealing with something fragmented; adding catalyst makes the epoxy cure faster. There are times when I need time to get fragments aligned; JB-KwikWeld works pretty fast, so there isn't always enough set-up time to get a lot of tiny fragments into position.

You probably already know this, but if you wrap the remaining Tech Steel in plastic, it will stay pliable and usable for years. I still have half a stick left, wrapped in a baggie; I orignally bought it back in the spring of 2004.

Modern epoxies are incredible products; I wouldn't hesitate to use them when more tradional metal repair (such as welding) simply isn't possible. Epoxies can't fix everything, and with some items I would only use epoxy for a temporary repair, but within limits, there's no reason why you can't take advantage of them.

Let us know if you ever have a problem, though I don't think you will, especially if the epoxy cured properly. I've drilled it, sanded it, polished it, tapped it, and painted it, all without a single problem.

Got a gas tank with pinholes in it? You've got the right stuff to repair it now...

I guess I've jinxed myself  Applied pressure again this morning and turns out the screw isn't sticking to the epoxy  I put some vaseline around the screw and re-applied the proxy. I hope it works this time. I can't think of any other easy fix.

Quote from: rock_rebel on September 01, 2011, 06:29:38 AM
I guess I've jinxed myself  Applied pressure again this morning and turns out the screw isn't sticking to the epoxy  I put some vaseline around the screw and re-applied the proxy. I hope it works this time. I can't think of any other easy fix.

You probably applied too much. Cure time is a function of the amount you use. Unless it's cheap epoxy, which is entirely possible, and it will never "steel harden" like it says.

I would seriously take it to a professional though. You should be able to find a machinist who will rethread that hole for cheap, or even install a heli-coil, which will probably be even cheaper. I wouldn't take any chances on something so integral to the running of your machine (and the catching fire of your pants...).

If the epoxy isn't sticking to the threads, you still might be able to solve the problem, AND make the screw removable at the same time... try this:

Fill the hole where the screw was with epoxy; once it begins to harden, use the screw to CAREFULLY cut new threads into the epoxy BEFORE the curing process is complete, then CAREFULLY REMOVE the screw and allow the new epoxy to FULLY CURE before you try to reinsert the screw. The epoxy should harden enough to make the threads retain their shape and work as functional threads, while NOT sticking to the screw, making it removable.

As I've mentioned previously, this is why I prefer working with a product (JB-Weld, for example) that I can ADD catalyst to; being able to "cook" the epoxy with a coat of catalyst makes it cure MUCH quicker. In fact, you could probably do this with JB-Weld, then dip the screw in the catalyst BEFORE you screw it back into the hole. This should make the threads around the screw cure quickly; the screw itself should still be removeable, and the threads should be tough enough to allow you to remove and replace the screw without ruining them, though it is obvious that you're not really concerned with that...

I know this can be frustrating, but let this be a challenge to your resourcefulness; I think you CAN kick this problem right in the ass, it's just a matter of finding the best method. The epoxy might not stick to the screw, but you should be able to use that to your advantage. If the screw is too long for the hole, use it to cut the threads in the PRE-cured epoxy, then cut the screw down a bit (Dremel with eye protection), or maybe get a shorter screw...

Dealing with these types of problems isn't always easy, but I think the solution is right in front of you. I understand why you chose the Tech Steel product, but JB-Weld allows you to add catalyst AFTER the curing process has begun, which is why I originally recommended it.

Go for it man; this forum could use an epoxy-repair expert, and you seem halfway to that point already...

If you were to epoxy a short length of stud into the hole and use a nut and washers to secure the bracket onto it you wouldnt have to worry about any threads and you will still be able to remove the bracket......or am I just thinking too hard 

Well, the obvious question seems to be, will the epoxy stick to the stud?

Keep over-thinking this Sledge! H3ll, I'm doing the same thing! rock_rebel has encountered more than his share of frustration with this GS, so along with you and a cast of thousands, I'm trying to help him with the problem-solving...

My guess is that if it will stick to the carb body it will stick to the thread  But hey...... if JB weld and all the other chemi-metal bodging compounds that are getting a mention wont, good old Araldite will 

OK, I had to use Google to learn about "Araldite", I don't recall ever seeing it on a shelf, or even hearing about it until you mentioned it earlier in this thread, so I figured it was another "UK-only" product not available in North America... turns out I was wrong:

http://en.wikipedia.org/wiki/Araldite

Looks like great stuff; I'm going to try to find some locally this weekend. If I can't find it here, I'll track it down next time I'm in Los Angeles... the more I learn, the more I want to learn, can't wait to start experimenting with this stuff...