Leaky Alternator cover... torque settings?

I’ve replaced the bolts on the cover and it now leaks.
Are there any specific settings to use?


Should I now remove it and replace the gasket too?

[Dukedesmo]

Does it have a paper gasket or threebond?

Personally I'd remove it, clean it all up and threebond it back. If you lean the bike over to the right you shouldn't need to drain the oil but you'll need to devise a means of pulling the cover away from the alternator magnets and make sure you remove the 'hidden' screw by the clutch slave.

I doubt there's a specific torque for the bolts, just a good firm 'tight' without going silly IMO.

Lean over to the right how far roughly?

Originally Posted by Dukedesmo

Does it have a paper gasket or threebond?

Personally I'd remove it, clean it all up and threebond it back. If you lean the bike over to the right you shouldn't need to drain the oil but you'll need to devise a means of pulling the cover away from the alternator magnets and make sure you remove the 'hidden' screw by the clutch slave.

I doubt there's a specific torque for the bolts, just a good firm 'tight' without going silly IMO.

[Dukedesmo]

Originally Posted by davkyt

Lean over to the right how far roughly?

As above, until it doesn't leak.

But if you get the bike level and see how far the oil is on the other (window) side then it's the same on the left side so, probably a fairly good lean angle required to stop it spilling out - certainly more than a 'side stand lean'.

For what it takes I'd drain the oil and if you really don't want to pay for fresh stuff just refill with the old.

If you're really concerned with threebond blocking the oilways then; you're using too much but there are gasket sealants* that get round the problem by only setting in the absence of air (anaerobic) with any excess just washing away with the oil, not sure if they seal as well though?

* e.g. Loctite 518 or for a cheaper equivalent this stuff; https://www.ebay.co.uk/itm/518-Anaer...53.m2749.l2649

Also, good call on checking the alternator nut torque whilst in there but you will then require a flywheel holding tool...

I’ll use the Three bond. Rather than squeezing **** loads out of the tube tho I might brush it on or use a smaller syringe

[Flip]

Originally Posted by Dukedesmo

If you're really concerned with threebond blocking the oilways then; you're using too much

I agree but my point was cautionary given the amount of spread possible from the 3mm bead they recommend.

As I say, the flexible silicone sealants are really cost saving exercises for the factories and being a bit old school I tend to make my own gaskets when they’re no longer available.

https://rover.ebay.com/rover/0/0/0?m...2F141462465314

[Albie]

As much as you may find a gasket Ducati now 3bond them on. Fairly rare to use one even if you do find one.

[Luddite]

DD and Albie have the right idea. If you look on any of the current spare parts sites you'll find that the part no. for the gasket has been updated and the new part no. actually refers to Threebond.

However if you feel you absolutely, positively have to have an actual gasket, there are some NOS Cagiva ones available from Italy for £25.

https://www.ebay.co.uk/itm/Guarnizio.../254203569543?

As far as torque settings are concerned, if your screws are M6x1, then they'll probably be the same as my Evo at 13.5Nm.

[alan s4]

I just bought this for my 916 crankcase, it's what ducati use.....

https://www.ebay.co.uk/itm/THREEBOND...frcectupt=true

[utopia]

If I read it correctly, the workshop manual for my later model (2001) 750 says 10Nm for the M6 casing screws.
I can't find anything specifically for the alternator cover .. only a general spec for "casing jointing screws".

If you're cleaning up and re-gasketing (be it threebond or otherwise) its important to tighten evenly.
My method is usually to refit the cover in question and fit all the screws, winding them in until they are still slack, but are just a tad short of snugging down.
Then I like to push the casing fully home with my hand and hold it moderately firmly while snugging the screws down using minimal torque (eg using a gentle hand and an allen key fitted "the wrong way round").
Only then will I apply some proper torque, and usually in stages, beginning with the same "wrong way round" allen key and a firmer hand and then the full torque.
In the absence of a torque wrench, 10Nm (or about 7.5 ft.lb) equates to something like a moderately firm hand on a std allen key (used "the right way round").
And importantly, all of this tightening should be done in a zig-zag sequence across the casing from one side to the other, to avoid tilting the cover. The first screw to tighten would be the one which looks most central to the bulk of the case, finishing with the outermost one.

If you use threebond, don't apply too much of it as you don't want too much of it to squidge to the innards of the case, from where it could later detach and get where it shouldn't.
Also beware of applying it where it could squidge into any oil holes or compromise any dowels.

[Flip]

Originally Posted by utopia

If you use threebond, don't apply too much of it as you don't want too much of it to squidge to the innards of the case, from where it could later detach and get where it shouldn't.
Also beware of applying it where it could squidge into any oil holes or compromise any dowels.

I'll completely second Utopia's advice there.

You have to remember the prime reason for using a sealant like Threebond is money saving on a factory assembly line- basically they no longer have to have a specific gasket for every application on each and every model the company produces.

In addition, they will have a very precise process in place for the application of said sealant and if, like the company I work for, it will be pneumatic with a set speed for the nozzle to move so that correct amount is dispensed.

For an idea, I did a little experiment at work today using a hand applied 3mm bead (as recommended for Threebond in the eBay listing in alan S4's post) of a similar sealant between two pieces of Perspex compressed under finger pressure.

You can see the kind of spread and the potential of the silicone getting into places it shouldn't.







Call me old fashioned but I would rather make a gasket from good ol' Flexoid than risk a blocked oil-way.

https://www.ebay.co.uk/itm/Genuine-F...941b2a1e3059d4

[Albie]

Until no oil leaks out basically. You may be better draining in your circumstance.

[Darren69]

Was gonna say, drain the oil and check alternator isnt loose while you're in there. Iirc on the 2 phase bikes there should also be a lock tab washer on there to help keep it tight.

[slob]

once the surfaces are clean, i smear a thin layer on one surface (usually the cover) and then stipple it with a fingertip, wiping my finger regularly with a clean rag to ensure there isn’t an excess to squeeze out on fitting.

[utopia]

Yep, I stipple it on with my finger too.
Much easier to control a uniform, thin film that way.