Hole in motor housing under pickup coil cover

Today, while cleaning up this '81 650 Maxim that I bought late last fall, I found that there's a chunk of the housing missing on the front of the motor directly beneath the pickup coil cover.



Anyone have a suggestion for how to seal that up? Thanks.

 

...that sucks.

 

-Take the cover off.

-CLEAN the area.

-Take another pic. I'm inclined to say "JBWeld" but you can't do it from the outside or when it's that grubby.

 

+1

 

I like BigFitz's suggestion. The only other solution I can think of at the moment, if you're feeling frisky (and I mean it), is to take the cover off and get a piece of scrap sheet metal and a rivet gun ready.

Mark and center punch the area about where you have your arrow on the points cover, but slightly toward the face of the cover as much as you can and drill for an 1/8" or 3/32" pop rivet. Cut your sheet metal to the size of the hole, but again adding the space to reach that rivet on the inside of the cover and squeeze a handful of that rivet gun.

Put the cover back on test for fit, file as needed and then once back on with the perfect fitment I guess some JB Weld in place or a bit of Bondo onto the sheet metal, molded, sanded all nice like, and I would assume it could stay water tight.

Alright so who thinks this is a pretty ridiculous time waster? IMHO it might work and at least it's knowledge gained if it does work. Especially for me since it's mostly improv ha!

 

Believe it or not, that was cleaned up. I actually had to go buy an impact driver to get that cover off.

SIDEBAR:
The impact driver set sold by northerntool.com is a piece of SH*T, (although many of their tools are decent and most are covered by a lifetime warranty).


Anyway, here's a pic from the other side.



I was actually thinking about JB Weld using some kind of sheet material as a backing "mold." Wondering how thick it I'd need to make it for it to be strong enough to hold up.

 

The sheet metal could be relatively thin in my opinion, The jb weld should do most of the work. When I was younger, and riding dirt bikes, I had a chain break and bust a hole just like that one in the case. Jb weld worked very well. Backing it with some metal and rivets may even make it last a lot longer. It sucks to see that happen to you, but at least it may be an easy fix.

 

As the piece is missing and any product you use requires the surface to be clean, use a Dremel tool or such to really get to clean parent material. JB Weld will probably perform for a time but may eventually fail.

You might look for someone to actually weld the area up.

 

There's no oil in that part of the housing, and no pressure. There's no stress on the case there; it's pretty much a distributor cap cast into the end of the motor. JBWeld would be ideal for this; I'd simply use a couple of layers of masking tape to create a "mold" for the outer surface and puddle it in. Use multiple applications if necessary to get it the right thickness. Once dry, "slice off" the excess with a Dremel and it will last forever.

If it was an oil-holding part, I'd agree with welding. But this is just a dry cavity and under no duress.

 

OK, JB Weld it is! I'll report back with pics once I get 'er done.

Thanks!

 

That looks like damage from a set of 2-point case guards getting bent into the engine housing when it was laid down. DAMHIKT -- the 3-point guards are the only ones I'd buy anymore. On my bike, then entire lower left bolt mount has broken off - still haven't gotten that permanently repaired yet.

Anyway - for your case I'd also say the JB Weld fix will be perfect - add a very tiny "lip" of it on the inside to help with adhesion and retension, and you're good to go. And remember the little hole to the right of the damage IS supposed to be there - don't plug it up.

 

I thought I'd post a couple of pics of the repair I made with JB Weld. It was hard to get the top image in focus but I think you'll be able to see it OK. The only thing I'm still wondering about is whether I should seal the repair with some paint.

 

Good job man looks pretty good. Almost like it wasn't there in the first place. What techniques did you use?

 

Thanks. I started with some blue painter's masking tape under the bottom of the housing. The first layer ended up being somewhat thin on the upper end because the epoxy was thin enough to begin with that it basically flowed down hill. After cutting and filing away the excess with a Dremel then a hand file, I did two more applications. In both cases I waited about an hour after mixing before applying the material. It just worked a lot better when it had a chance to set up more. I still ended up keeping an eye on it and "pulling" the material upward with a small screwdriver a few times to try and keep it more uniformly thick.

 

That repair looks excellent.

Like a previous post, I had the same "motorcross bike with the chain through the case in front of the drive sproket" situation years ago and the JB weld fixed it. (And that was an oil-containing part of the engine case.)

 

Nice, that's a good patching job. You got lucky with the location of it. My buddy had a street legal enduro and the neutral sensor screw came out in the sump, moved under the primary chain gear and punched a hole right in the bottom of the crankcase.