Copper cylinder gasket or not?

Commrades

I was going to order a copper gasket for the cylinder barrels, to have on hand while I was going to decide to go with a gasket or not (return if not)
and the parts fellow ( British Cycle Supply , Nova Scotia) said that the copper gasket has dimension to it enough to change compression.

Said it was ok to use if I had done a rebuild..........but I haven't........I just have everything apart for inspection and all seems fine for now.
So he's sending me the regular gasket to use.

I understand you gents have talked about this issue many times..........but is that true about the copper gasket?
Changing compression that is.

Appreciate your thoughts!

is it a 750 or 850? on an 850 .015 base gasket is good for an average change in compression of 1/4 point. if it is a stock 850 than it is already a low compression engine and I would NOT drop it more. if it is a 72 combat with 10-1 I prefer to machine the top of the piston for a small drop because of the poor gas in the US. how thick is this copper gasket?

I'm not sure Bill.........I didn't end up ordering it.
The bike is a '74 850 MKll
Does anyone go with just the regular gasket anymore?
I remember reading about going with a silk thread and just use Yamabond or Hylomar Racer Blue?

Copper is still the most universal but if they make a FlameRing for 850's that's what i'd like best. Avoid the gasket that is a paper like composite with a thin copper foil around the bores and of course the now rare for good reason Al kind.

I just put a copper one on a Combat and coasted all surfaces with Hylomar as anti-weep experiment since Hylomar is good to 600' F and heads rarely see up to 400'F, usually 350-75' F tops unless a balls out racer or ignition time error. Early spring should know how it works out. I torqued the snot out of the head bolts too as saves some of the re-nip ups after cool down till all crushed down and stable-ish.

Are you talking about a head gasket or a cylinder base gasket? Different items altogether.

For head gaskets, copper tends to leak oil in front and flame-ring tends to blow out after a while. Pick your poison.

For cylinder base gaskets, I believe they were paper from the factory. My 74 MKII didn't come with one at all.

Hm, subject line say cylinder gasket, so maybe the bottom not the top of it?

DO NOT use paper as base gasket, it crushes down to lose clamp force then hot oil oozes out. Steel plate or better, nothing but sealant on barrel base.

I realized if the Hylomar holds up, next time head off I'll try w/o any gasket just Hylomar alone, which will up CR a tad, which should feel and sound a bit better.
Will check squish band still adequate but suspect it will be fine, just closer more functional to help avoid detonation the slight CR increase may cause.