Grasping at STRAWS to fix broken carb post.

[79XS11F]

I have still been having some issue with my carb bowls overflowing into my air box on my 1978 restored bike so i have the carbs off again to see what's going on. While I have the carbs apart I decided that I would repair the one broken post that I have on Carb #1. I wasn't sure how I would do it but figured JB weld would be involved. The only question was how to create a form to shape the JB weld into an acceptable post. While I was going over this in my mind I was by happenstance picking up straws off the kitchen floor. The cats love to play with them. It occurred to me that these straws were very close to the same size as my carb posts. Off to the garage I went and WOW, the straw fit snugly over the post and created a near perfect form to shape the post. I cut the straw off at the right height from the shoulder of the post and mixed up some JB. I added it to the form and removed trapped air with a tooth pick to make sure the JB was in full contact with what was left of the post. After about 4 hours I sliced the straw down the side and removed it. It came off very easily. I then used a drill bit being turned in my fingers to create the pin hole on the newly formed post. I used the pin hole on the good post as a guide. I used a sharp razor blade to flatten the sides of the post so it would not pinch the float.
This morning the newly formed post is as close to perfect as I could have ever expected it to be. I'm sure that the larger straws like those you see in milk shakes would fit over the base of a fully broken post pretty good as well. Heat shrink tubing would also likely work well.
This repair was so easy and fast, and worked so well I figured I would share it with you. Here's a few photos.

[XS1100 Newbie]

That was good work on the post, but keep in mind, that JB weld will deteriorate in gasoline. Not sure how long it will take, but maybe long enough to get another body. Crazy Steve has a repair that is more permanent.

[jetmechmarty]

I can tell you from experience that your repair will fail. In my case, I suffered a backfire and subsequent fire.

I carried mine to MOTORCYCLECARBS.COM (site down) and had the post welded. The fix is permanent.

It may or may not be more cost effective to replace the body.

[79XS11F]

Well that sucks, I was sure that JB as good to go with gas. If not I will redo the repair the same way with gas safe epoxy.
Rob

[79XS11F]

According to this link JB is go in gas?

http://jbweld.net/products/jbweld.php

Rob

[crazy steve]

Nope, it's only 'resistant' to most chemicals, not 'proof'; big difference. Gas will eat it up over a fairly short time. You might try one of the 'gas tank repair' expoxys, they are designed for constant exposure to fuel but whether the strength is there I can't say...

[jwhughes3]

Coating it

What about coating the JB Weld in something gas safe? Like a 2 part urethane paint to protect it from gas?

John

[BA80]

The straw idea is a good one. If you could find something that's heat resistant to replace the straw and do the repair with acid core solder it would work great.

[TopCatGr58]

Hey Greg,

Folks can find both steel and aluminum tubing that could be used as a straw for applying the molten solder! I've seen them in fairly small diameters.

79SF,

I had repaired my broken carb post a decade ago with J-B Weld full strength, not the "quick" version, and it held up for a while, but did break down/melt!

I then found some special metal impregnated epoxy putty called QUICKSTEEL, it's been so long I can't remember if I actually found their Aluminum version, but I used it to repair the post...kneaded it to activate it, then molded it around the base and upper broken post, let it cure, then used a dremel to grind away the excess so that the bowl would fit, etc.! It's been on there for many years now, and is still as hard as nails, etc.! Here's the link to their website!

http://bluemagicusa.com/index.php/bl...d_epoxy_putty/





T.C.

[79XS11F]

Yes I have seen small DIA thin wall copper tubing at hobby shops and that will be an even better fix. I will have to take one of these straws to the hobby shop and see what they have. It would have to be pre shaped to slip over whats left of the post but that could be done in a vise, to make it more oval in profile. If thin wall copper tubing can be found in the right DIA, made to slip over whats left of the post and filled with solder, the fix would in deed be permanent.
Rob

[BA80]

Hey Greg,

Folks can find both steel and aluminum tubing that could be used as a straw for applying the molten solder! I've seen them in fairly small diameters.

79SF,

I had repaired my broken carb post a decade ago with J-B Weld full strength, not the "quick" version, and it held up for a while, but did break down/melt!

I then found some special metal impregnated epoxy putty called QUICKSTEEL, it's been so long I can't remember if I actually found their Aluminum version, but I used it to repair the post...kneaded it to activate it, then molded it around the base and upper broken post, let it cure, then used a dremel to grind away the excess so that the bowl would fit, etc.! It's been on there for many years now, and is still as hard as nails, etc.! Here's the link to their website!

http://bluemagicusa.com/index.php/bl...d_epoxy_putty/





T.C.

There ya go.

If you could do it with the lead though and make it stick it would be a permanent repair.

[natemoen]

There ya go.

If you could do it with the lead though and make it stick it would be a permanent repair.

Yeah, use some body lead, butter (no not real butter) the inside of a pipe so it doesn't stick and fill the pipe with the body lead.

[spyder]

carb body

I have several bodies here and would be more than happy to send you one...just pay the shipping. Tell me what one you need and it's done. We just have to keep these old gals on the road.

Spyder

[79XS11F]

I have several bodies here and would be more than happy to send you one...just pay the shipping. Tell me what one you need and it's done. We just have to keep these old gals on the road.

Spyder

Sent you a PM

[79XS11F]

So the BAD news is that although the straw makes for a perfect form for the shaping of the pots upper end the JB weld did in deed fail very quickly.. So I have a carb body coming and in the mean time i am going to continue to seek a way to fix this cheap and easy. I picked up a few sizes of brass tubing at the hobby shop yesterday pretty cheap. I will try Top Cats putty first with the plastic straw and go from there. Keep you posted.
Rob