I have been cleaning/replacing/replating as many little parts as I can while doing my conversion. Last week I replaced the square rear transmission cover at the the tail end of my tail shifter with a newly replated cover and a fresh factory gasket (thanks again Doctor Evil). The thing now leaks like crazy.

When I went to replace this gasket several years ago, I could not find one locally and did not have the time to order one (I was driving the car daily), so I made my own from cork gasket material that I purchased at a local FLAPS. Worked great for 15 years.

The factory gaskets are paper. I am wondering if it is to thin and/or has a lack of compression thickness. I am assuming that they are a dry install. Would it be a total hack job to add a bead of RTV to either side of the gasket? I have one new one left. I sure dont want any of that stuff getting into the transmission.

Or - I can get out the cork and the sissors again.......

Any thoughts are appreciated - thanks!
Scott S

If you choose to use a sealant, a thin layer (NOT a "bead") of Permatex "Ultra Blue" or "Ultra Black", well massaged into the paper gasket on both sides, would be OK. Just make sure it's applied so there's not a lot of excess that can come adrift in there once the gasket is installed.

The Cap'n

an alternative to rtv, i use a product called hylomar (permatex and locktite) i think both market it. developed by rolls royce for jet engines. a thin smear seals everything up nicely and the beauty of it is it does not harden. i have been using it for years on leaky british motorcycle enginges and it really stops the oil hemoraging. also teardowns are easier later on.fwiw.

I would love to find that this is true, God knows I tried everything else and nothing ever worked, but I'll also be damned if I'll buy another BritBike just to find out.

by lothars hammer i swear it true. my commando is sitting in the same spot since last winter and there is not a drop of oil around it. yamabond on the cases, pematex spray copper on the head gasket and hylomar everywhere else. there is no cure short of glyptone for the porous castings though and i have seen it fail in cases so i dont uses it. fwiw.

by lothars hammer i swear it true. my commando is sitting in the same spot since last winter and there is not a drop of oil around it. yamabond on the cases, pematex spray copper on the head gasket and hylomar everywhere else. there is no cure short of glyptone for the porous castings though and i have seen it fail in cases so i dont uses it. fwiw.

Tried the RTV thing last night – still had big leaks. Per the Capn’s advice, I refused to simply load the thing full of RTV and “squish” it shut.

The thing did not leak before – what the hell changed? The cover plate changed. I had picked up another one to send out for replating so I would not have to drain the transmission and leave it open while I waited for it’s return (and while waiting to find the time to re-install it). The “new” cover plate was junk. It was twisted and it appeared to be made of thinner metal. The flanges were also just a touch shorter. Sure looks pretty though.

I hit the original plate on the wire wheel, painted it up and threw it on. No more leaks.

Note to self – inspect your parts. Especially before you make them look pretty.

Loctite IS Permatex, and has been for years.

The Cap'n

Yeah, my Norton didn't leak either after I put it back together. Used an old aircraft powerplant method of putting a silk thread in the middle of the sealer. But this is a sheet-metal part, not milled pieces.

You're sure it has oil in it right?

I've used thin copper wire. Never thought of silk thread ...................

The Cap'n

Dang,

Never thought I'd hear the Cap'n admit there was an engine build trick or two that predated him...

i am pretty sure all the oil is in the sump as it has been sitting unloved for a year.

I'm surprised too. That was one more BritBike trick that never worked for me, but we used it on aircooled VW's in the 60's, supposedly stolen from the aircraft guys.