Points / Advance Housings: o-ring, gasket or both?

[patentgeek]

This relates to a 1970 XS650 (XS1) engine.

Since I'm installing a Vape/PowerDynamo crank triggered ignition, I removed the points/advance mechanisms and housings (#21 in the parts diagram) and am installing Heiden Tuning covers for aesthetic reasons.

When I removed the housings, they were only sealed with red o-rings (no gaskets). But the Heiden Tuning cover description says "We prefer to use new gaskets and o rings: 18-0863 and 18-0889." When I checked the parts manual, it's a bit unclear as to whether the points/advance housings are sealed with o-rings only, gaskets only, or o-rings and gaskets. The tappet covers seem simiarly confusing.

Hoping somebody here can provide clarity.

18-0863

 

[jpdevol]

I use both on the cam covers (OEM or Shell), not used Heiden, but likely the same.

On the older tappet covers, I think gaskets are preferred - don't currently own one (shopping)

 

[5twins]

On the older valve covers, you must use a gasket because there's no groove for an o-ring. Advance/points housings usually have both, at least later ones do anyway.

If someone swapped newer valve covers with the o-ring grooves on, then you could use o-rings. I actually prefer them, they seal nicely. The P.O. of my '83 put gaskets on along with the o-rings, and plastered gasket sealer all over them too, lol. They leaked badly. I cleaned all that crap off, installed new o-rings, and they seal fine now.