I sent Bob Carpenter a brand new out of the box 'Busa head back in 2000 for his CNC port job. It came back looking as if the work was done with a sledgehammer and chisel. By the time I got all the surfaces matching and the rough edges smooth and the intake plenum seperator to have a consistent shape, the motor had lost torque and would only produce horsepower in the last 20% of the rev range at best. If you go with a Carpenter head plan on having to back it up with NOS, thats the only way you can be sure it'll make power. I would not buy a spark plug from Carpenter if he had the last one on planet earth.Carpenter Racing offers this. For a Third Gen it's $1400 if you send them the head. It's done by CNC, port polish, seat. He says a dyno proven 10 hp for 2008 and up ZX10.
... and provided that the bottom end can take the higher revs!Bigger ports = more high rpm power provided you have the corresponding matching cams.
Yes, you're right; but again, is a matter of what cams you'll be installing.... and provided that the bottom end can take the higher revs!
Arbitrarily making the ports bigger on an engine design that has a fixed maximum RPM limit won't necessarily make more power, will almost certainly cost midrange, and may cost top end power.
Garth has been using the MototuneUSA approach, and making the ports smaller in a critical area.
Again Garth, have you taken a look at the gixxer1K head?with the flow bench tests I have seen on a epoxy ported head it outflows a stock head everywhere until you get in the .440" lift range which no one even makes cams that large so I for sure would not open any part of the intake port. My bike has never been faster with a epoxy port (on my 2mm motor) it was the only time the bike would love the higher rpm's and pull sooo hard on the top gears. 200.2mph is still my bikes current fastest record..... I'm going to test to see what a stock motor with head work will do this weekend