MT,
Stock CB/CD/CL175 headgasket thickness is .052". Think real hard
before you reduce the thickness on a stock engine. Any gain you make
in compression ( hp ) will probably be lost because you'll also be
retarding the cam timing.
I wouldn't recommend copper, try a Cometic gasket in the CFM-20
material, they make it in various thicknesses (not at many as
copper). On a street bike you want a good seal, copper can be
finicky.
Any fractional hp gain you'd get would hardly be worth the trouble
and possible reduction in reliability.

Your CA has 16" wheels?
JohnnyB


--- In CB175RaceTech@yahoogroups.com, MTucker <mtucker436@...> wrote:
>
> Back working on my CD175 and CA95 after a bout with Lyme diease
(not recommeded) no more yard work for me.
> New questions:
> 1.) Anybody have any or a source for the 3 odd Honda screws for the
petcock on my CA95? They appear to 5mm x 22mm with a .9mm pitch and
everything I find is a .8mm pitch.
> 2.) I am going to pop off the head from my CD 175 with 100 psig
compression measure the stock head gasket and order a thiner one 
Does any one know the stock thickness and what would they recommend
as a minimum for copper?
> 3.) Same question for the cyclinder base gasket, the stock
thickness is?
> 4.) My CA95 tank and petcock are pretty rusty, I have done a lot of
cleaning, purging etc. Anybody have one for sale?
> 5.) Best source for new tires and tubes for the stock 16" wheels
for street riding and the fall Giro?
> The people making the Woodstock movie want to use it if I can get
my bikes reliable enough. Any others want to rent/lend your bikes?
> Thanks,
> MT  
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