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Oil-tight Alternator Cover

Discussion in 'Supersport (1974-2007)' started by chueewowee, Nov 26, 2020.

  1. Hello dear friends,

    I've got my SS 600 engine out for a repaint. So of course I'm attending to the little things too. (oh and changing the seat and subframe, re-working the harness - it's my bike...painting the tank blue..!! details which I may post for interest on another topic later on)

    There was a very slight weep from the alternator cover - this occurred after using hylomar sealant, with careful cleaning, perhaps could have been more thorough on the oil removal from lip, but not much.
    I'm happy to give it another go with Hylomar - this time I've emptied all the oil - last time I hadn't - just leaned the bike, but I have a feeling it may weep again.

    I don't like weeping at all.
    What do you reccommend, over and above Hylomar for this job? Another sealant? A paper gasket?
     
  2. I use three bond, but any decent engine sealant should do. Clean it well and make sure no residual oil makes its way out while you are trying to close it up as this will comprise the seal
     
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  3. Don't use blue Hylomar....if you have to use Hylomar, try Instant Gasket Clear........however I switched to 3 Bond and found it much better.

    Leave either for 24 hours before you refill the oil.
     
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  4. +1 for ThreeBond. I think most of the main manufacturers suggest it for use during some stages of engine assembly, and some loosely attach their own brand (e.g. "Suzuki Bond"). A quick search suggests that it may be available via a Ducati part number, but then it will cost even more, and it's not cheap anyway. It looks to me to be a silicone rubber type material, but I would avoid using bathroom sealant as an alternative!
     
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  5. 3 out 3 for ThreeBond then. Thanks all, for kind replies.
     
  6. Once you have the mating surfaces clean and before you apply the ThreeBond, wipe the surfaces with acetone to ensure they are free of any oil. If you can't find acetone easily, the rash of pound shops sell it as nail varnish remover - though some of the stuff on offer boasts to be 'Acetone Free', it is usually on the shelf next to the proper stuff

    Alternatively, if you have Choke and Carb Cleaner, get some on a cloth and use that.
     
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  7. Can’t wait to see the before and after pictures of the engine refurb.
     
  8. Loctite SI5699 flange sealant works really well and is easy to apply and to remove.

    However, you might want to use a paper gasket for the alternator cover just in case the stator coils need that extra few thou clearance and foul the flywheel if no gasket is fitted. This happened to me, and parts of the stator coil wiring rubbed through against the flywheel. I'm not certain if it was a badly manufactured stator or not having a gasket that caused the lack of clearance on my engine, but I always use a gasket now to be on the safe side. Those stator coils aren't cheap.

    If you buy some oil-proof gasket material (ebay, etc) it's quite easy to make your own gaskets. There are plenty of youtube tutorials to show how, and it's so much cheaper than buying gaskets. Takes about 10 minutes to create a gasket for the alternator cover. It helps if you have a few hole punches but you can manage without.
     
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  9. Thanks Borgo,
    I'll do that. My usual practice is to use isopropyl alcohol, or meths.

    Now then, do you think that acetone or carb cleaner is superior, then?
    I ask, because I do believe that absolutely clean is important.
     
  10. Thanks, Yeah, I actually like making paper gaskets, and have hole punches. In fact, I prefer that gasket paper to the kind often sold.
    I've decided to try without a gasket once again, but if it doesn't work with Threebond, I will go for a gasket in that case.

    Not sure why the hylomar isn't working, I never had problems with it in many years.. of course (i do beleive) gaskets (with or without cement) are superior overall.

    It may just because the surface were not clean enough... I took great care, but notice the old hylomar seems to have shifted off the surface too easily.

    I've made a note of that sealant you mention; It's often recommended.

    I suspect the Threebond is more of a hard drying cement, though perhaps a little flexible, with a strong bond. It may be more effective here then.


    As for clearance, I'm sure my cover does not foul the stator when fitted without gaskets. Actually I'm surprised to hear you say report your fouling, because the bikes were originally fitted without gaskets.
     
  11. Ah, that's interesting. In that case, the cause of the damaged stator coils on my bike must have been something else. Perhaps the flywheel thingy had come loose at some time prior to my ownership. I only discovered it when investigating a problem with the charging system. That's when I found that a couple of the wires on the stator coils had chafed on something. The only thing I could think of to cause it was that a gasket had been omitted, causing a lack of clearance. Looks like you can ignore my recommendation to fit a gasket then!

    Are you really painting the tank blue! That's heresy, isn't it? :eek:
    Be interested to see the finished result.
     
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  12. An alternative method for using flange sealants is to apply to one surface as usual, but leave to set a little for perhaps ten minutes.

    Now apply a very thin smear of clean oil to the mating surface.

    Assemble the joint without fully tightening the bolts and leave overnight before fully tightening.

    You will now have an oiltight seal but when you next want to remove the alternator cover, it will be easy to remove as the sealant will stick to only one flange face. In fact it forms a permanent gasket (with Loctite Flange Seal anyway) that stays on the face of the casting and can even be reused as it stays flexible.
     
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  13. 3Bond is very flexible and very sticky when using it, but it wipes off clean from outside the casing when wet or peels off dry.

    However, it fills the small gaps and dints that other sealants tend not to.

    Red Hermetite IMO is completely outmoded by more modern sealants, it is/was bloody messy and bastard to get off.....Blue Hylomar was IMO slightly better, but not by todays standards....I always found it went a bit jelly like if oil got into the joint.

    Hylomar Instant Gasket (silicone based) is pretty damn good but not as good as 3Bond.....as a much lower cost alternative though, it's worth having some.
     
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  14. Advice offered is interesting. The quoted 'alternative method' was one I've had success with with car rocker covers, and was thinking about. I am very tempted to try it here.

    I also found the Hylomar 'Blue' is a bit 'jelly-like' in contact with oil, when not used as a sealant with paper gasket.
    I am guessing the HYlomar you think is better for this purpose, is the 'Hylosil' instant gasket.

    One other solution I was considering, but have never tried, is Copper RTV Silicone Instant Gasket Sealant. Has anyone any experience with this?

    The two I am now considering to choose from are:
    3bond is, (which is unusually, rubber based). Promises to be the 'guaranteed' solution.

    Finally, one I once used on another vehicle, 'Hondabond High-Temp Silicone Liquid Gasket for use in areas not requiring a solid gasket, such as cylinder head covers. It Dries quickly, remains flexible.
     
    #14 chueewowee, Feb 4, 2021
    Last edited: Feb 4, 2021
  15. Did this job for the first time this winter. Used 3 bond grey. Applied to both surfaces and then left over night and carefully cut off the over spill
     
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  16. I have got good results with Loctite 5926 Blue Silicon. Have good resistance against oil en heat.
     
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  17. I agree with all on here who recommended Three Bond

    That stuff is miraculous and really easy to apply
    .... i wish it had been around back in my BSA days .... :)

    Once cured it's a bit like an elastic band , except that it never perishes .
    Highly resistant to both oil and heat ....
    I reckon you won't ever want to use anything else again .

    I got a 250g tube last year from these people -

    Three Bond 1215
    £12 plus £1 P&P
    speedsport.co.uk

    Note - the word " Ducati " is not written on the tube .... Ha !
    :cool:
     
    #17 oldtech, Feb 4, 2021
    Last edited: Feb 4, 2021
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  18. Related question, where is the oil coming from to get into this area, and where does it go to if we successfully stop the leak with sealant?
     
  19. LH Alternator cover has alternator and gear linkage as well as starter gears. All these are washed in oil under pressure from the sump via holes in the sump case side. Sealant helps the metal to metal faces seal
     
  20. Ah thanks
     
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