Shaved engine to frame screw thread

[BubbleOz]

:cry:

So here I am fixing the eternal MZ oil leak
Then notice, the top bolt connecting the engine to the frame sticks out. All the threads are polished clean... Except the first quarter turn.

I was able to just pull out, has anyone had that before?
Recovering from shock until I try a fresh bolt... Somehow this seems like a headache I didn't want!

[Puffs]

No, never had anything like that. Maybe it wasn't tight?

Not sure which bolt you're talking about,

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the upper of #2?
Then also check the nut side.

[BubbleOz]

Thanks for the response, it's #2.

I worked out what happened. The threaded bit has snapped
In the case . I know engine is still solid as the hole where it came out lines up perfectly.

It does mean that a bottom end or gearbox rebuild will require new case half..

Bolt was torqued properly, can only suspect metal fatigue...

[Puffs]

No I don't think it's all that dramatic, but a hassle it will be.
If I remember correctly (look that up somewhere) the RH of those fixation plates (whatever you call them, they hinge on rubber) has a nut welded onto it, because that side is a bit awkward to reach. You can probably just screw the old bit out (towards the inside?) & re-fit with a new bolt. At any rate, don't see why this would require work on the case halves.

Maybe you can get the old piece out through the LH hole? Sounds like building a ship in a bottle...

[dave47]

I agree, it won't need splitting the engine. The difficulty might be fiddling the engine out of the frame, if the broken bolt is holding it in. There is normally about 2cm of thread on the bolt, so there will be more than 1 cm sticking out, in which case a bolt extractor from the RHS is the best bet.
Edit: I've now realised it can't be done. The rhs of the bolt is inaccessible. Hopefully there will be enough play in the engine plates to get the engine out.

[Blurredman]

An interesting problem!

[Puffs]

I'd leave the engine in place, and try something else first. (It might be a bastard to get the engine out anyway, if a bit of that bolt sticks into the case.)

If you can drill a hole in what's left of the bolt, from the LH side (so through the bolt hole in the case), and then try to screw in one of those bolt extractors:

and then, once you feel some resistance, lift the engine (with a jack or so), to take off the friction in the case hole, you might get that end out & the sun will shine again.

You probably need to make an extension for that extractor.

Good luck!

[BubbleOz]

Thanks for the responses everyone!
Yes I remember the welded nut, which is inaccessible. Still the problem is one of only drilling and collapsing the screw with the engine supported.
I am content that everything is tight (enough) to not make it an immediate problem - it just so happens my 3rd gear started skipping, but seem to overcome any issues riding the clutch!

Screw extractor could work, but as someone that snapped one when using the wrong size.... Probably best to drill, or pivot the engine when that time comes.
Until then, will put it altogether and pretend this isn't an issue. Yet.

Thanks and stay safe everyone,
Nik

[Puffs]

When the time comes to take the engine out, and if there is a bit of a stud sticking into that case hole, take off the swingarm.

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[BubbleOz]

Thank you appreciated.

I think once all screws are loosened should be able to pivot the engine, but easy it won't be. Swing arm approach might help.

Thanks,
Nik