sealing oil leaks in a horizontal joint

[twas_brillig]

I've got a 99 Buell motorcycle (it has the Harley V-twin in a sportbike chassis) and the rocker cover is leaking. The shop advised it was a 2.5 hour job to drop the engine and replace the gaskets (at $ 111/hr). Decades ago I had a Triumph motocycle with vertically split engine cases and I found some sort of product back in the day to put on the outside of the joints to stop the leaking.
Anyone got suggestions? Otherwise, it'll give me something to do on a weekend.
thanks,
Doug

 

[aeronca65t]

With VW air-cooled cases, we always used #2 Permatex and a continuous piece of cotton sewing thread all around the joint.

Not sure if that was "official" but it worked.

 

[Westfield_XI]

Hylomar? Aviation boxer type engines use a silk thread between the case halves to prevent leakage. I always thought Triumph motorcycles only stopped leaking when they were empty.....

 

[twas_brillig]

Niall - sounds like that was something you did on assembly of the cases, rather than wrapping the thread around the exterior??
Westy - oh a touch! I'm cut to the quick!! Actually, you've got me wondering about our old BMW R80 R/T (which has been sitting under a cover for about 5 years - is it horizontally split or vertically?
Doug

 

[DrEntropy]

Porsche engines are similar to the VW cases, Porsche has a "$pecial $ealer" for 'em... but no matter what material you use, the only way to stop the leak is to R&R the cover and reseal it IMO.

 

[Billm]

The VW "factory approved" fix was just the equivalent of Permatex (as of 1969 when I worked for VW of Switzerland for a while)
BillM

 

[aeronca65t]

........sounds like that was something you did on assembly of the cases, rather than wrapping the thread around the exterior??....

Yes...this is when you're assembling cases from scratch.