Damage to crank case - Can it be fixed?

Morning (Here in Aus) All,

Was finally prepping for engine rebuild, have stripped engine down completely and was getting it ready to send off to machine shop for cleaning, measuring and a bit of work but on inspection have found the following damage -> https://imgur.com/a/YaFx5Xj I hope that link works. There is damage to one of the upper crank case mounting holes. Looks like someone has already tried a repair. Damage to the inner oil filter mounting and damage to one of the crank case cover mounting holes.

Can the much smarter than I people on this forum give me a view? Can someone TIG this up and rethread?

 

@Jadds - it seems like a machine shop would be a good place to ask about the viability of a repair.

Having said that, here is my opinion:
-- Inside bit of the oil filter mounting area: Who cares? It's fine. Run it.
-- Upper crank bolt: See if they can make some sort of repair (TIG it and tap it, whatever). If not repairable, then you have to ask what your goal is - if the goal is to make a museum piece, then you've got a problem. If not, stick a bolt in there, seal it up good (which you need to do anyway) and run it.
-- Crank side cover mounting bolt: Repair if possible. If not, see above question about the goals of the project, you can always run with 3 screws holding the cover on. Don't worry about it. Ask me how I know.

These engines are pretty forgiving. If you did nothing I think it would be perfectly serviceable, but if you have somebody capable of performing a repair that would be better, of course.

 

@Dan Gardner Thanks Dan, not a museum piece, this will be a runner (I hope).
I shall bring it to a machine shop for some guidance. And please do tell about running with three screws on a crank cover

 

-Engine side cover bolt isn’t gonna be a problem
-oil filter isn’t gonna be a problem
-I am concerned about the case bolt ….as long as it goes deep enough to reach proper torque I’d thing it would be ok, but I’m not gonna bet my life on that.

 

Welding is best but there are modern epoxies (Belzone as example) which can even be machined and tapped for threads.

 

This case has been missing a side cover bolt for years. I think I had the bike a couple years before I realized it was even missing. Someone did a decent repair of the mating surface with some sort of epoxy or something - but didn't bother to build up a place to thread a new hole. Anyway, this is a daily driver, and it's been fine for years, so I'm just going to keep running it with three screws.


In your case, the left side cover is a little more important since it has the timing stuff underneath, but it should still be fine. In fact, there is a drain hole at the bottom, so the seal doesn't need to be 100% perfect in the first place. But even with just 3 screws holding it down, it should be fine.

 

Sadly not in the UK

 

Yeah, thats my worry too. The top of the repair is rounded off and there does not look like nearly enough material to support a proper torque. And the bolt will not be flush.

 

Is that an imgur UK block thing? You using a VPN?

 

Interesting. Will see if welding can be done but this might be a good backup.

 

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Au works

 

Well, you have the cases apart, so the obvious move is to take the cases to a tig welder to build the broken screw thread up, ditto the stripped one, cut it off, weld it up, drill and tap. Just make sure the paint locally is removed and the casing is clean - no professional will thank you for bringing a many oily casing to be welded.
The oil filter can be left as is...

 

I had never tried Belzona - so I decided to try some out on some parts I needed fixed. Belzona 1111 to be exact.

First, the stuff is expensive. It only comes in a 1kg kit. By my estimation, buying 1kg of JB Weld would cost more, so even though it is a big upfront investment, it's not unreasonable in my opinion.

Long story short, I think the Belzona is great stuff. Having now tried it myself, I think it would work just fine for the repairs in this thread.

 

I have a similiar, but a much smaller, repair to make on a non-critical area on a smell carburetor. I plan to try to repair it using JBWeld as follows. I am going to first screw in the bolt. Then I am going to very carefully coat the exposed bolt threads with
oil or maybe grease trying to not get any on the casing. Then I will build it up with JBWeld, allow a day for it to completely harden and then very carefully unscrew the bolt which should be free since the coating of grease should prevent the JBWeld from
adherring to it. If that works then I will finish off the JBWeld to match the original casing. In my case only about 1/2 of the threads are missing. If you don't have to really torque it down the JBWeld idea might work for you. If not, then take it to a
machine shop. Good luck.
I

 

When I was researching the Belzona stuff, I came across a video where they used a Belzona specific mold release agent for doing exactly what you are talking about.

I just did a little research and it seems like there are a lot of opinions out there for what a good release agent for JB Weld is - might be kind of a black hole to start looking into.

Might take some experimentation to figure out what works - especially if is finer threads on a carb or something - IMHO.