Bought another one! Let the work begin!

[storm 64]

Looks like maybe it's a stater clutch bolt. Maybe the starter clutch let go and caused all the damage... 🤔

[Nessism]

More bad luck. Sorry for all the hassle.

[Buffalo Bill]

Ok, situation like that can happen. New engine? New block? Keep the pistons?
Bonne chance

[Rob S.]

Just realize the 1100ED is arguably the pinicle of air cooled Superbikes. And exhaust baffles? We don't need no baffles!

[1978GS750E]

Yeah Norm, a starter clutch bolt was my first guess too. But there is no way that a starter clutch bolt can get into the #1 piston/crank cavity???? The odd thing is that this is the only part of the case broken. The top half looks like new on the inside. Here is a picture showing a wider view of the broken area:


Now my question is......can I repair the broken area since it looks to not have any real pressure on it?

All the rods (except #1 has a few nicks) and bearings look and feel great. No other damage anywhere in the crankcase that I can see.

I am guessing that someone dropped a bolt into that #1 piston/crank cavity, ran it and the bolt bouncing around broke the cylinder sleeve and chewed up the piston skirt before breaking this area of the crankcase. Now since these crankcases are made of unobtainium, I guess a repair is in order, if possible.

I have a stock set of pistons and cylinders headed to me now. My thinking is that the 1134 kit has such thin sleeve walls that it caused the sleeve to break easier than normal. (of course, the bolt is going to break something!)

Sound plausible? Can it be repaired?

Thanks!

[TeamDar]

There are windows in the cases underneath the main bearing. That is a starter clutch bolt. It is short because it broke. It is beat to *@%^$*@%^$*@%^$*@%^$ because it bounced around under the number one piston and rod after it found its way through the window.

[Nessism]

Since that's an internal web my guess is you will be okay with that piece broke out. Oil will sling and fill up that cavity though which may be a bigger problem. One other option is shape a replacement piece and have it TIG'ed in place, then file it flat. I'd be inclined to go that route but since the aluminum has been in oil for 30+ years the welder may experience a lot of splatter.

[1978GS750E]

My apologies Norm and TeamDar! After removing the crank I can see where the bolt could have gone through one of the two passages. Weird thing is that there is no scaring in the stator area and no missing bolts!

I guess someone could have picked up an extra bolt while the stator was off and it got magnetically held while they put it back together??? Who the #$%%& knows?

Yeah Nessism, I was thinking the same thing about the TIG welding. I wonder if a high-grade metal-filled epoxy would work?

[1978GS750E]

Got a set of stock pistons today for the pig! Cylinders should be here on Friday. Ordered new rings from Cruzinimage.net. Have a bunch of gaskets to order from Parts Outlaw. Still have to find someone to do the TIG welding.

I might have this thing together by Halloween, ..........or Thanksgiving, ........... or Christmas! Ah heck, lets shoot for Brown County next year!

[Carter Turk]

That tray area is in the last photo is where I found all my starter clutch screws. I had that same broken area tig welded.

My guess is when the starter clutch bolt was longer the counter weight on the crank flung the bolt into the case.

[1978GS750E]

Yeah, I'm trying to find someone to weld it, but as soon as I mention "motorcycle crankcase" they say they can't do it! WTF?

[Nessism]

Yeah, I'm trying to find someone to weld it, but as soon as I mention "motorcycle crankcase" they say they can't do it! WTF?

It's because of the oil. It's gonna splatter because oil gets into the pores of the metal. Best soak the entire area in MEK or similar to degrease.

[salty_monk]

They are scared of all the oil & the fact that it has to be oil tight... I bet a lot of welders have been burned welding something & then having it leak later. Any hot rod shops around you? Maybe they'd be more inclined to take a look at it...

[Grimly]

Belzona or Devcon would be the answer over here. You will have similar there.

https://www.cromwell.co.uk/shop/materials-and-maintenance/engineering-coating-and-repair-products/plastic-steel-putty-a/f/9025?query=Devcon

https://www.cromwell.co.uk/shop/materials-and-maintenance/engineering-coating-and-repair-products/500gm-inchsfinch-plastic-steel-putty/p/DEV7112019K

[1978GS750E]

Thanks Grimley, I have a bunch of Devcon metal filled epoxies, since I used to sell them! I'm hopeful that I can find a welder that will tackle this, as I am concerned about the epoxy bonding to the oil-soaked aluminum. I feel a weld is the way to go if I can get it done. We shall see! I don't want a piece of epoxy coming loose and rattling around in there, doing more damage!