RazorBobSr wrote:
Shop foreman tell me that to get TO
45ccs,they had to remove .170 from MY head,have I messed up,or WHAT
RazorBobSr,
The amount necessary to shave from the head will depend upon the original
compression ratio. Later heads require a large amount of "shaving" to
achieve higher compression ratios. For example, I had a late head, that
required .175" to be removed to get it to 10:1 CR. You can get a rough idea
of your CR by measuring the head from valve cover sealing surface to head
gasket sealing surface. Here are the measurements (from the Triumph
TR250/TR6 Competition Preparation Manual):
7.75:1CR = 3.550"
8.5:1CR = 3.460"
10:1CR = 3.375"
12:1CR = 3.295"
As far as actual combustion chamber volumes, the manual gives the following
data:
41.6 cc = 10:1CR
33 cc = 12:1CR
Anyway, to sum it all up, you are probably OK, but measure it just to make
sure.
Hope this helps,
Hugh Barber
Hollister, CA
'73 TR6
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