Top Cover Gasket Alternatives for SF/Cs

piranha-bro2

piranha-bro2

Hero member
Location
Melbourne
Having noticed that virtually every SF motor I dismantle has a bow in the top cover where the gasket at the corner studs has crushed, does anyone know (Clem?) if copper could be used in place of the fibre gasket? Or any other suitable alternative that wouldn't allow the top cover to deform at the corners?

The gasket only has to seal the oil coming up the middle studs and the splash from the camchain and rocker assemblies. O-rings could seal the studs. I almost feel no gasket would be better than the std fibre, but the height reduction could potentially cause problems
 
Dellortoman said:
A gasket works by being soft enough to conform to the shape of the gap between the mating surfaces. If you go for something more solid you may have trouble getting it to seal.
Click to expand...
Yes. My racing mate used to use aluminium sheet with sealant. He would assemble it loosely without properly compressing the sealant, and tighten it fully the next day after the sealant had set. My top covers are so far from flat that I didn't even bother trying it. The rear left corner is always split on the gasket any time I take the cover off, there is very little material around the stud on the head casting, but there has never been an oil leak there. I have considered building it up with DevCon type stuff for more support, as otherwise the gasket looks re-useable. However I just use a new gasket each time, if buying I order three so I alway have a spare.
 
Interestingly, i flattened mine on the face plate on initial assembly. When i pulled it apart, it had bowed again. Didn't leak though. I flattened it again, new gasket, it hasn't leaked in 10,000 km.
 
martymoose said:
Interestingly, i flattened mine on the face plate on initial assembly. When i pulled it apart, it had bowed again. Didn't leak though. I flattened it again, new gasket, it hasn't leaked in 10,000 km.
Click to expand...
I think because there's very little oil getting about behind the section where it bows. I guess I'll just live with it!
 
Reckon you'll only get around the issue with a far stronger cover Quentin. Maybe milled from billet.

The head castings are a bit skimpy at the edges, I usually find the gaskets squashed at the corners. Haven't had any issues despite distorted covers, they always seem to adapt. I also run a bead of 510 around the outer perimetre, just in case. ;)

piet
 
Not a big enuff issue to warrant that, Cam. The top cover is securely mounted to the rest of the donk and the top engine mounts and creates the strong stressed member link - it's a nice rigid package on the twins. It just irks me seeing the gasket squashed at a couple of corners and the top cover bowed.
 
The top cover distorts because of cornering too hard, Quentin. Because the SF hasn't got a proper frame, the whole engine twists and distorts if you don't take it easy, and they seize can pistons mid-corner as a result. I remember you explaining this to a guy once, you should remember, there was no way he would buy such a bike.
 
Tippie said:
The top cover distorts because of cornering too hard, Quentin. Because the SF hasn't got a proper frame, the whole engine twists and distorts if you don't take it easy, and they seize can pistons mid-corner as a result. I remember you explaining this to a guy once, you should remember, there was no way he would buy such a bike.
Click to expand...
Easily fixed by using a Segoni frame with a cat installed in the main frame tube. The cat will give signals that keep the orientation of the motor in phase with the frame. Marnix can probably explain this better.

Jim
 
You must log in or register to reply here.
Back
Top