Gas Cap Gasket

[badbmwbrad]

This R65 group has a lot of knowledgeable folks and I appreciate all the help I've received with my new-to-me 1983 R65LS.  

My cap couldn't be removed.  I reviewed the design weaknesses of the fuel tank cap at Anton Largiader's site. Considerable force was applied to unscrew the cap.  It ratcheted three clicks and I stopped.  

It finally came off after a bit of penetrating oil was sprayed beneath the rain skirt.  I don't know if there is any internal damage to the plastic core or to plastic ratchet housing surrounding the lock barrel.

The original rose-colored cap gasket broke up and has been replaced with a new double-lipped gasket ordered from MAX BMW.  

The seated cap rocks and wobbles on the tank.   Is this typical?

[Barry]

The seated cap rocks and wobbles on the tank. Is this typical?  

That's a sign that the new gasket is not the right dimensions - probably too thick. When I replaced my 30 year old gasket while I was waiting for a new one to be delivered I made do with a standard O ring which actually worked Just fine once I figured out the right size. Fitting O rings of different thicknesses I could get the cap to wobble as you have described. With a gasket of the correct thickness screwing down the cap puts tension between the lower part and the top part removing the wobble.

[Mike V]

Brad,

To the best of my knowledge the only available replacement gas cap gasket is for 1977-on airheads and is a different configuration than the OEM cap seal.  I found as you, it does not fit the tank filler lip as the original, but it does seal adequately and well with a little "wiggle" at the cap and seems to be typical for this fitment.

51 25 1 453 148   Gas Cap Gasket 77-on Airhead.

I also had to replace the cap ring or rain guard on my cap and it too seems to be of a different material than the original soft and subtle material.  The replacement is quite stiff and seems to be made of plastic instead of the OEM soft rubber.

16 11 2 307 360   Gas Cap Filler Ring.

Even though I've never had serious trouble with any of my caps other than having to drill a vent hole, I heed the warning of others and never tighten fully or use the lock. Looking for wood to knock on...

-Mike V.