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Topic-icon 1989 R100GS Rocker Cover Replacement

  • jarthur
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4 months 2 weeks ago - 4 months 2 weeks ago #4646 by jarthur
1989 R100GS Rocker Cover Replacement was created by jarthur
Will be replacing the rocker covers shortly. Should I use any gasket sealer when replacing the gaskets?

Thanks,

Jack
Last edit: 4 months 2 weeks ago by Wobbly.

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4 months 2 weeks ago #4647 by 8053
Replied by 8053 on topic 1989 R100GS Rocker Cover Replacement
I have never used any sealer on rocker covers.

James Strickland, IL. Airmarshal

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4 months 2 weeks ago #4650 by Wobbly
Replied by Wobbly on topic 1989 R100GS Rocker Cover Replacement
That was a very hard thing for me to accept, but Jim is correct. Amazingly, rocker covers require no sealant.

I can only add the rather obvious additions...
• New (or different) rocker covers will require new gaskets
• The most critical part of the job is not the gasket, but rather the torque used on the center fastener
• Later model covers are marked "L" and "R" so that they can be returned to the same positions

Hope this helps.

Don't hide 'em, Ride 'em !!
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4 months 2 weeks ago #4654 by 8053
Replied by 8053 on topic 1989 R100GS Rocker Cover Replacement
Wobbly is correct about not over torquing these, or anything on an airhead. The rocker gaskets on my R75/5 have been there for many years. If you check your valves on a reasonable interval, you might never need to replace those gaskets. The only time you must replace these is when they tear when removing the covers.
I am working thru an R80RT that is new to me, and I am finding many fasteners that are over tightened. A simple rule of thumb is that if you can not un-wind any bolt or nut with the tools in the OE tool kit, it is over done.
The lock nuts on the swing arm and the nuts holding the rockers and the heads in place (cylinder studs) are the exception. Setting the steering head bearing pre-load, for example, is more of an art than a science. There is a torque spec for the top nut, but this is only relevant after the bearings are set correctly. Same for the swing arm and the wheel bearings.

James Strickland, IL. Airmarshal

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4 months 2 weeks ago #4655 by jarthur
Replied by jarthur on topic 1989 R100GS Rocker Cover Replacement
What is the recommended torque for the center fastener? Outer nuts (although I doubt I can get a torque wrench on those)?

Thanks,

Jack

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4 months 2 weeks ago #4656 by Wobbly
Replied by Wobbly on topic 1989 R100GS Rocker Cover Replacement
You'll need to consult your workshop manual for details. Sorry, I'm not near my books at present, but the important bit is this.... The cylinder head alloy is extremely soft. Due to the nature of the alloy and 40 prior years of over-tightening, I would de-rate what ever reading you find on that center fastener by at least 2 ft-lbs.

The two 6mm side fasteners will be around 5 inch-lbs, but aren't going to be near the same issue because the valve cover is a much stronger alloy.

All 3 fasteners have specific washers, which need to be in place.

Don't hide 'em, Ride 'em !!
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