1985 K100 intake sealant

[GJBushman]

I am finally getting around to replacing the rubber intake mounts on my 1985 k100. I can no longer keep the idle under 1300rpm due to vacuum leaks. The instructions in my Haynes manual state "On replacing, apply a thin coat of sealant to the stub mating surfaces and tighten...." No mention of what type of sealant I should be using. Any suggestions? Thanks.

[jpevehouse]

Did my intake and of course did not use a sealer- missed that in the german language notes I was using. Have some Three Bond Liquid Gasket 1194 on my shelf now and am waiting for a slow weekend to break everything down again.
Should go faster the second time.

[der ziegelstein]

I used Permatex Ultra Black. This is the same stuff I use on my valve cover, etc.

[deilenberger]

I used a thin coating of RTV.. black of course..

[GJBushman]

Thanks folks. I get the picture.

[walt3022]

I've been wrestling with this a while, and I'm well and truly frustrated at the moment. I bought a new-to-me 1985 K100RS last fall and proceeded to bring the maintenance up to date. That included renewing the necessary rubber bits. I found the bike was engineered without apparent thought of how one replaces the throttle bodies (TB) and related connectors with the engine in place. There is insufficient space between the top of the plenum and the frame to press the assemblies into position. I struggled with this but after two attempts finally succeeded by: lubing the rubber connectors and the TBs, heating the former with a heat gun to soften them before assembly, fitting the rubber connectors to the plenum first, then pushing the unit onto the TBs and, finally, pushing the rubber connectors home on the TBs with a large flat screwdriver and securing them with hose clamps. (Incidently, the connectors between the TB and the head were sealed with Dirkko.) This all was waaaay more work that should have been necessary. But, after this, the bike idled and ran very well.
I subsequently took the bike on its first long tour. On the third day out it began to run poorly: the idle speed dropped, and it lurched badly, seemingly unwilling to hold a constant speed or accelerate smoothly. These symptoms point to a new air leak in the intake tract. Ever the optimist, I hoped this poor running was the result of the Throttle Position Sensor having slipped out of adjustment. But no. I'm really bummed about this, as I enjoy the bike when it runs well, but this problem could be the kiss of death to long term ownership.