Question: repair sand cast aluminum engine case?

[hailwood1965]

I now own a motorcycle with a horrible repair job on an engine case, which I think is made from aluminum.

It weeps a bit of oil according to the PO.

He didn't want to talk about how it happened. We think he is getting divorced.

My thought is to repair: clean entire surface, then remove all the putty/JB Weld and silicone. Weld/repair the hole or whatever until it is level with the engine case cover. Drill and re-tap?

Suggestions welcome.

 

[larry4406]

I recall @zmotorsports doing a beautiful repair to an aluminum motorcycle engine casing. Stripped oil plug hole if I recall correctly.

Maybe he can step in and offer some help.

Until then, search his thread for details.

 

[Firebrick43]

I now own a motorcycle with a horrible repair job on an engine case, which I think is made from aluminum.

It weeps a bit of oil according to the PO.

He didn't want to talk about how it happened. We think he is getting divorced.

My thought is to repair: clean entire surface, then remove all the putty/JB Weld and silicone. Weld/repair the hole or whatever until it is level with the engine case cover. Drill and re-tap?

Suggestions welcome.

What motorcycle is it? Highly unlikely that is sand cast, it appears to be diecast.

you can hot tank and bake the part to get all oils out, get a carbon rod, machine it to close tolerance to slip in the hole and weld it up with tig. Then machine it back to outside profile and re tap.

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But you are likely to warp the case doing so. Might have to make a tapped plate to hold the part flat to limit warping.

Possibly cheaper and better to get another case from a motorcycle breaker

 

[hailwood1965]

It's an MV Agusta.

I'm not taking it apart. I want it fixed in the chassis. I am aware this is not a textbook or NASA-level repair.

 

[Firebrick43]

It's an MV Agusta.

LOL by the pictures that only covers 35 years and dozens of models from all across the lineup.

I'm not taking it apart. I want it fixed in the chassis.

Good luck then!

 

[hailwood1965]

I realize and have been clear it's a hairball-level fix. **** happens.

In 2000 Kenny Roberts Jnr won the 500cc GP (MotoGP) world championship. In the race that won the title Suzuki was out of cylinders and Junior ran warm-up and the race with a cylinder that had been epoxied with a Japanese version of JB Weld. Again, **** happens.

 

[The Cobbler]

I'm not taking it apart. I want it fixed in the chassis.

good luck with the repair. your plan sounds less than ideal, but c'est la vie

 

[Firebrick43]

I realize and have been clear it's a hairball-level fix. **** happens.

In 2000 Kenny Roberts Jnr won the 500cc GP (MotoGP) world championship. In the race that won the title Suzuki was out of cylinders and Junior ran warm-up and the race with a cylinder that had been epoxied with a Japanese version of JB Weld. Again, **** happens.

I am confused now?

You wanted to weld it in the first post but now are espousing the wonders of metal filled epoxy?

JB weld or bellzona can work as an in place repair. Put a release film of wax or petrolum jelly on a bolt and stick it in the hole, it will form the threads. Apply the epoxy and use a rotary tool to shape it on the out side profile and a fine mill file to shape the gasket sealing face.

 

[theoldwizard1]

you can hot tank and bake the part to get all oils out ...

I'm not taking it apart. I want it fixed in the chassis. I am aware this is not a textbook or NASA-level repair.

Any remaining oil/contaminants will mean that it will continue to leak or fail (fall off) completely.

At a minimum, the case in that are need to be thoroughly heated !

 

[Firebrick43]

Any remaining oil/contaminants will mean that it will continue to leak or fail (fall off) completely.

At a minimum, the case in that are need to be thoroughly heated !

Like i mentioned in post #3?

"you can hot tank and bake the part to get all oils out"

 

[ArcIndWeld]

The way I'd do it is clean it all up preheat the case to about 250-300f weld it up peen it with a ball peen hammer all over the weld area, weld again, slow cool to room temp under welding blankets and then grind to shape, re drill and tap and use an engraver / needle scaler to reapply the cast finish if needed. then ideally machine or file flat the sealing face.
It would **** to do in bike and wouldn't be ideal but it is doable with some slight modifications to the pre and post heating to account for seals and other goodies nearby.

 

[driftpin]

I'm no pro machinist or welder, but it's an MV Agusta, it deserves some time, skill, and attention. Then again, if it was a Honda 305 that you first rode 55 years ago, for personal reasons you might want to do the welding and finishing to last your useful lifetime, and to be a functional motorcycle for those to whom you leave it.

Unless you're talking about some 125cc early 1960's MV Agusta, not capable of 100+MPH speeds, you sure don't want to have your 'fix' fail at triple-digits speed. Do it properly as discussed here, or jury-rig it and play the odds. That said, odds-are, you will be repeating the half-baked epoxy repair, or other.

 

[Firebrick43]

The way I'd do it is clean it all up preheat the case to about 250-300f weld it up peen it with a ball peen hammer all over the weld area, weld again, slow cool to room temp under welding blankets and then grind to shape, re drill and tap and use an engraver / needle scaler to reapply the cast finish if needed. then ideally machine or file flat the sealing face.
It would **** to do in bike and wouldn't be ideal but it is doable with some slight modifications to the pre and post heating to account for seals and other goodies nearby.

Look at the pics, its not sand cast. Its pressure die cast and doesn't need any of those techniques.

I don't know why the OP is so secretive about what model it is but it has a trigger wheel for the ECU so it knows timing for fuel injection and ignition. I think the itailians call them phonic or phoneic wheels?

Probably late Cagiva era of ownership, maybe later. A Brutale, F3, F4?

 

[Fixr]

I now own a motorcycle with a horrible repair job on an engine case, which I think is made from aluminum.

It weeps a bit of oil according to the PO.

He didn't want to talk about how it happened. We think he is getting divorced.

My thought is to repair: clean entire surface, then remove all the putty/JB Weld and silicone. Weld/repair the hole or whatever until it is level with the engine case cover. Drill and re-tap?

Suggestions welcome.

Speaking as not a real welder and not a real machinist, and definitely not a motorcycle racer, but someone who respects all of those:

Clean and chip and scrape away everything that isn't the original metal, take and post lots of pictures so we have some idea of what we're dealing with. There are too many layers for anyone to see through. Any good repair is going to demand clean bare metal regardless.

I think I see a crack in the *epoxy* as if someone screwed the fasteners into a hole filled with silicone sealer. But that doesn't matter. What really matters is the remaining original metal. If it's aluminum, it can be welded back up a little at a time, redrilled, tapped and likely filed back flat enough to seal to the side cover. But it needs to be clean.

 

[TheEquineFencer]

I was just scrolling and saw this. Let me bounce an idea. If you grind out all the Epoxy and other **** that didn't come with it to start with using a Dremel tool. Then you have clean metal. Since I don't think aluminum will weld to steel or even SS easy. Given there are threads left in the block, if there's enough threads to hold a bolt in, if you TIG or use one of those gas welding rods for Aluminum, weld and build up the area around the bolt and use a Dremel to get the outside back to shape. It's just an idea.