I have been in dscussions with Dave (dmcca) who will be doing my head modifications. He has since signed up with this forum and will no doubt have some info to post into this thread himself. Hopefully some nice pictures as the work comes together.
So far we've decided that I will install the piston, and cylinder with the piston set with the exhaust ports at BDC. I will then take squish measurements (solder method), and calculate the trapped volue (sealing rings with grease and cc'ing with metho up to the bottom of the spark plug hole).
After this I will be sending the entire S3 cylinder and head (and insert that gives the tightest squish) to Dave to work his magic. He has a nice workshop set up and in particular is building a database for the software he uses to simulate effects on engine behaviour prior to modification. He will be taking measurements of the S3 cylinder and will be able to provide feedback how it compares to the standard cylinder and if any port changes have been made (other than cleaning up casting). So far he has taken measurements for a 2010 EC300R (NSE.ONE) and an EC250 (was this yours Lonetree? - AHH ROBKTM dbw). By running sims he will then determine the best gasket stack to meet my desired goals and then machine to spec. He also agrees with F5 (tighter is better) so we'll see what he does. The insert will also be corrected for volume to achieve whatever CR I want.
We confirmed the head and insert will both require the same amount machined off them to make sure that they seal, which will make the other 2 inserts redundant. If anyone with a S3 head wants them shoot a PM.
Dave has been really great to deal with and explains everything in nice simple terms. He's located in Australia (at the other end of the country from me) and seems to be building his business up nicely. If anyone else is thinking about going this route I wouldn't hesitate to recommend him based on my experience, or the feedback received by others who've had his work.
One last thing from Dave re the 250 he worked on: "I also mapped out the stock ignition curve and the dual map switch simply changes the entire curve by 2-3 degrees. I advanced the base timing by 2-3 degrees so that the 'wet' curve is now the same as the old 'dry' curve, and the new 'dry' curve has a little more oomph down low but still revs out fine." I may consider doing this to my bike also as I have never run the wet curve, even in the wettest conditions as a 300.
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