If your original gasket is rubber, then it needs to be replaced by rubber. The update from cork is also rubber. The gasket needs to be thick enough to make up for any surface irregularities between the two parts. I personally have never had any problems using either a heavy cardboard stock or roofing paper in all the years I've used it. The roofing felt like some gaskets will some times stick to the surface after its been in place many years, and needs to be scrapped off.
Most gaskets were or are impregnated with asbestos for heat dispersion, or graphite. I would say the heavy card stock or roofing felt is better than the graphite, since graphite when wet will start to corrode iron and aluminum. I am not trying to upset the gasket industry I just wanted to let people know there are options if they are the DIY type like myself. I am not sure if Smithers has ever had any problems using homemade gaskets, I myself have not, in the 25 years that I've made my own.
If you're not comfortable making your own, or fear that a home made gasket is inferior then by all means buy them pre-made. Some people wanting to restore one of these bikes, will pay some one else and never touch a wrench, others will do everything except get into the motor then take it to a shop for that part, then others will DIY everything they possibly can including gaskets, paint, refinishing bolts, etc. like myself.
It's a matter of comfort and experience as to how much into a build someone wants to get. I personally haven't ever had a ca95 motor apart or set ones points or timing. I have however, done motor rebuilds, porting and timing and valve jobs on much more complicated engines on other motorcycles and cars. The ca95 engine isn't much different just a little foreign but not intimidating.
So please anyone doing a rebuild etc. do what is in your abilities, no one has the last or final word on whats best for the bike except you as owner so please bear that in mind
