Thanks for the help guys.
The big bore piston sizes are:
555 Big Bore kit = 59mm
605 Big Bore kit = 61mm
Both of these kits use a one piece oil control ring. I believe the three piece oil control rings are better than the single units.
I also read in an old article “Gentlemen’s Express” that CB750 pistons with modified crowns where the way to go. Maybe the CB650 (59.8mm) pistons with stock rings and a modified crown would be a better way to go. It shouldn’t be difficult to turn the dome to match the CB550 head and compression could be tailored to your own specifications.
Comments?
I would bet the .2 mm difference between the 605 kit and the stock cb650 head gasket would not be a problem at all.
And as for machining the cb650 pistons....
I don't doubt you could machine some off the crown without problems, but as to how much I dunno.
But with a little machining and mabey double up on the base gasket you might be able to keep the compression from going sky high.
If I had a set of cb550 pistons to compare i could make a more informed reply... but I have no 550 parts at the moment.
Anyone have a set of 550 pistons (or even a single piston) they are willing to spare?
I'd like to see how different they are.
Anyone know what the minimum thickness of the dome that is run-able and not blow through the piston?
l8r