Hello
89 XT 600 Kick only USA

Help needed on magnesium case. Picked up a parts bike with an over tightened case cover bolt. See photos.

I do not have the piece that was broken off.

Without the broken piece there is no structure to hold in a coil straight as well.
Have my doubts if I JB weld up the hole then tap in a helicoil.

Also if anyone knows if i could drill in further and add coil, or not enough metal

Thanks

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Sure it's magnesium? Looks like aluminum, and a magnesium crank case is vanishingly rare.
Definitely a weld job if you plan on using the bike A good welder should be able to do a nice job on that, completely filling the hole. You'll want to drill the hole with great care, you don't want to be on an angle and have to weld it up all over again.

Of course you could always ignore it and see if it leaks without the screw...

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Grant Johnson
Seek, and ye shall find.
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Inspiring, Informing and Connecting travellers since 1997!
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Yes aluminum, cover is magnesium. I'm looking into a welder around me that could help. Thanks

It wasn't leaking too bad with the cover and case Jb welded and no bolt but it was leaking. It's always the bottom bolt

I think you could live without that bolt completely if you sealed the cover with a decent engine sealant on both sides of the gasket. Somelike like Dow Corning grey. (Which is what BMW use on all their gasketless cases. Definitely worth a try. JB weld doesn't belong in this job. You could even forfit the paper gasket entirely if that doesn't work and just use a sealant. As It would reduce the gap even more. Again, worth a try.

Welding is obviously the best option. It's not the easiest weld though.

It would need to be ground all the way out. Then filled from the inside out. Then drilled and re-tapped.

For that job to be done the case would need to be squeeky clean. And you would need a skilled TIG welder. And then a steady handed engineer to recut the thread.


Another option (and perhaps the best) is to install a threaded M6 aluminium stud into the broken thread and secure the stud with a tack weld. Then you could just put a nut on the stud from the outside. This could even be aligned with the case itself.

You would have to carefully file out the broken thread until you can slot the new stud into place. It's a very easy weld.

The stud would probably hold in place just with JB weld (on the thread of the stud and used to build up the case around it). As long as you're very careful with tightening up. It would only require the lightest of torque to make the case seal. So you would use a Nylock nut in this case.

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Excellent advice thanks.
I was originally looking if if i could possibly drill in slightly further into case to get a coil. Its a close call!
Or double up the helicoil but there is not enough structure.
I think you have a great idea with the bolt. I wish I could just get a coil in on the case side then fill up around the bolt with JB Weld, keeping the threads out on cover side to be secured with a nut.


Thanks!!

Looking at coil size to possibility

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Don't drill it deeper, you'll go through into the sump and then you'll be in a whole new world of pain. As a 'get me home' I'd say use sealant each side of the gasket in that area. Longer term give it to a good engineering shop to weld the case and redrill/tap the hole. They'll probably need the engine out though.

Use two of the helicoil on the bolt, then apply a thin layer of JB inside the whole, stick inn bolt with helicoil on and use JB on the outside, before its all dryed up undo bolt. It will hold, its only 10nm.

dont know many welders that will like to work on an assembled engine,


even if you drain the oil, the remains wiill start burning or worse. so to do it right they will want just the case naked.


The helicoil (or two ) costs almost nothing to try...



as for drilling, if yuu dissassemble all the stuff in the picture, you should be able to measure how far you can drill befroe coming out