1955 BSA C11G

[Rip-It-Up]

That repair on the gearbox looks scary. Certainly isn't going to hold enough to seat the gaskets and prevent leaks. You pretty much could have glued the bolt in the hole and accomplished the same cosmetic fix. Not trying to be negative but you might check with some local machine shops and see what they would charge to fix it. What they would do is build up a weld, drill it and retap a new hole, and surface it flat again. Might set you back a few days but personaly I would want the reassurance that it was fixed right. Probably wouldn't set you back to bad, and probably save you from running it dry or getting oil on your back tire.

[Swagger]

I have to agree, it won't hold for any kind of actual riding.
I've have some aluminum bungs threaded and welded into the case but it really would probably be cheaper to just replace it unless that's a bit of unobtainium?

[dgrady77]

I thought everything on a 50s Brit bike was made of unobtainium.

I'm thinking I'll let it sit for a while and work on some other parts.  While I work on those other parts, I'll decide what to do about the gearbox.  I'm checking ebay, but if I'm ready to come back to the gearbox before I find a replacement, I'll work more on fixing it myself.  That being said, I believe the case is aluminum.  If I were going to fix it myself, what would my options be, as far as welding, brazing, or something else? Some things to consider... I don't mind the rod being permanently attached to the gearbox case, unless someone knows of a good reason why it shouldn't.  Second thing is that I have an implanted defibrillator so I can't use an arc welder.  It would have to be a flame.  I've never welded, so whatever I do, I'll be doing a lot of practice on scrap metal before I bring a torch anywhere near my gearbox.  From what I've been reading, it seems that because of the case and rod being dissimilar metals, welding them to each other would be out.  So would brazing be strong/heat-resistant enough to hold them together?  How hot does a gearbox get?  I also like the idea of not melting the existing metal.  I know I'm being stubborn and possibly unreasonable about fixing it myself, but I think that's kind of a common trait on this forum, isn't it?

[Hoofhearted]

Repairing that box shouldn't be that difficult.  It can be built up, drilled and tapped, and faced.  Check this stuff out.  I am itching to try it.  Looks like das wunderchild for alloy.

[bikeboy]

Looks like das wunderchild for alloy.

wow! lets us know how you get on if/when you do. That looks really useful. I'll bet it's expensive 


ian

[dgrady77]

Looks almost too good to be true, Hoof.  I'll see what I can find out about that stuff.

[Hoofhearted]

The rods are $65 a pound.  But right now I'm trying to save for Bonneville.  I will have to try it at some stage. 

[dgrady77]

I wonder how far one pound would go.  I've been searching Google for reviews, but I'm not finding much.  It's mostly "has anyone tried this stuff?" with no replies.  If the VA ever pays up, I may go for it.  I've wasted more money than $65 before.

[Swagger]

I've messed with it a little, it's ok but it's not a substitute for "real" welding where you want to put things under stress in my opinion.

Were it mine and a suitable replacement couldn't be located for anything cheaper than a kidney I'd have it welded. I'd turn and thread some aluminum bungs, say....1/2" diameter with a rounded end, to match the stud's thread pitch. I'd then mill out the broken portions with a 1/2" ball endmill so that the turned bungs can be pushed into place. Using the other portion of the case for alignment I'd then tig the bungs into place. It'd be plenty strong and a guy who took his time with a dremel and some files etc, could blend them externally pretty nicely I'd think.