Thanks for the info! I don't have the pistons here, they're over in the old man's workshop waiting for me to do something with them, so I've had to do some 'guesstimate' calculations as to how whether the pistons could work with the 650 head. While the CB750 "300" model pistons are flat tops, thus have no "dome"
, they do need some height machined off to fit in the 550 block as per the "Gentleman's Express" mod (see here:
http://forums.sohc4.net/index.php?topic=20601.0). I am
hoping that there is about 3mm worth of height to play with, because then machining to suit the 650 head (ie steeper than the suggested 15 degrees) will give me a ratio of about 9.45, which is fine for my street usage as my goal is get more power through increased breathing and not compression. After reading other threads where people were concerned that they would have to much CR with the GE mod, this is reassuring me a little bit. I'll have to go over and take some measurements.
Thanks for the info on the rods too, I thought it was the other way around, I must have gotten mixed up somewhere
. So re the easier acceleration of the piston, has this increased your revs as well? Out of curiosity, what do you run it to?
Also out of curiosity, what gasket are you using to suit the 62mm bore? Custom?
(
And no, no German ancestry.)