« Reply #107 on: August 25, 2020, 10:03:36 AM »
Later 392 K7 pistons to get some extra CR?
Looks like it. That was a "hop up mod" in 1980. 
Today you can take the CB750 DOHC stock-bore pistons and cut a 1/2" flat around their outer edge (of the crown) to clear the valves, and net a 9.6:1 CR in the early heads (with a 1.0mm overbore, first).
Are you saying the dohc pistons into the sohc? Are you doing this mod? I didn't see it on the website.
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Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner
Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A
