Gasket Sealants

[bra725t]

Can anyone advise of a decent gasket sealant for engine casings? I have a continual oil leak on my alternator casing that starts when the revs go above 2500 rpm.  I have tried several silicone sealants but leaks continue.  

[scrambler]

I use red RTV Permatex silicone sealant or something like that, but if you have such a heavy leak and no sealant can stop it probably you are facing some more serious issue that can`t be fixed by switching to a different type of sealant. The alternator cover originally is sealed by a paper gasket. Did you try to spot the origin of the leakage?

[bra725t]

The leaks coming from the bottom of the alternator case just below where the oil feeds through from the sump.  I replaced the original casing when I got the bike and fitted a new gasket but this leak has never stopped.  The original casing was sealed with some sealant that was spongy and incredibly tough to remove. At lower revs than 2500 there' not a hint of oil but a steady seep starts when above 2500rpm

[retromech]

Is it possible that this leak is coming from the area of the points, maybe the famous leak from the points drive shaft seals ?

[retromech]

Re my above reply, should have asked if you talking about leak from inner or outer alternator cover, sorry, brain asleep!!!.

[Leif]

Hi there.
I had exactly the same problem, proved to be a hairline crack in the bottom of the cover, not easy to detect.

[bra725t]

It's definitely from the bottom of the alternator casing and not the points, points are completely oil free with new seals. It's the inner casing thats leaking, at first i thought it was the balance shaft adjuster that was leaking but I found the oil was running back from the alternator to the balance shaft while the bike was driving. I had a nightmare cleaning the gasket surfaces on the crank cases of the previous owners sealant as they use a sealant that was impervious to any cleaning agents i tried.

[bra725t]

Thanks for that hint ill check my casing tomorrow for cracks