How does H-D come up with a 9.3 - 1 comp. ratio ? Myself and 2 other head porters have gotten 93cc on a STOCK 110" head with stock valves. OK. Do the math {or use Bigboys calculator} and with a .040 stock hg that has a 4.020 internal dia. { I just measured my stock take offs} and 2cc valve pockets in the pistons ,you will come up with 9.72 - 1 comp. or if the heads are 95cc like H-D says ,you will come up with 9.55 - 1 comp. How do you get 9.3 - 1 
AND one more thing ,Andrews grinds the S.E. cams ,and they are not grinding them {255} to the #s listed in the S.E. book. Ask John if you don't believe me. Dewey ps. you can't hold ,whats not in your hand.
Assuming a deck height of 0.0” with 95cc chambers it looks like we are talking about a 3.2cc difference to arrive at 9.30:1. If the valve pockets are 2cc apiece, the CR pencils out to 9.39:1. The CR would calc to 9.30:1 with a -0.006” deck height and 2x2cc pockets, or 2x1cc pockets w/ -0.015" deck height.
I see the ’09 brochure lists a 9.15:1 CR for the 110; they also round the stroke up to 3.380”. This is beginning to look like a conspiracy to me.
Save yourself a call to John Andrews and just for grins ask your tuner to check the SE 255 cams against the published spec.
Speaking of conspiracies, my conspiracy theory begins right here with naitram. I believe that naitram is really Bill Davidson, and has been placed here under cover by H-D to drive Hoist out of his mind! Well I say mission accomplished;
you can take off the disguise naitram!
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Topic: Comp. ratio on a CVO 110"" motor (Read 11151 times)