MZ Skorpion/Yam 660 primary drive gear nut..

[A100man]

For those not aware this apparently has a habit of loosening off over the years to create a potential grenade if it lets go completely, so general advice is to check it when you acquire such a machaine

So I duly bought a new clutch cover gasket and took teh cover off to check mine out. I have to say the gubbins inside looked great (apart from a slightly rusty water pump impeller) and the nut of doom still appeared to be done up tight with tab washer securely in place..

..but do I now

a) Leave it

b) Untab the washer and check torque with suitable wrench potentially needlessly meddling

c) Other checks as yet unkown.

Ta
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Now: A100, GT250A, XJ598, FZ750

Then: Fizz, RS200, KL250, XJ550, Laverda Alpina, XJ600, FZS600

[WD Forte]

Dont know the bike, but I'd probably try a spanner or adjustable on the available flats to see if I could work the nut at all.
If it was tight and there was no appreciable end float when trying to push pull the shaft or observable wear, I'd be inclined leave it alone and check again in a period of time or miles depending on how the bike is used.
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bikers smell of wee

[stinkwheel]

You could always mark its position with a punch or file mark then re-check at the next service.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[A100man]

[A100man]

[jeffyjeff]

You might consider using a thread lock liquid for some added peace of mind. Loctite green is a medium-strength threadlocker that can be applied to assembled fasteners. It wicks into the interface between the male and female threads.
Bear in mind that "needless meddling" is my knee-jerk response in a situation like this. I would probably remove the nut-of-doom and apply a generous serving of high-strength threadlocker before installing the lock tab washer, torquing the nut to spec, and perhaps staking the exposed thread for good measure.
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History shows again and again how nature points out the folly of men - BOC

[sickpup]

[WD Forte]

Of course, welding is an option I spose..........................
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bikers smell of wee