Topic: piston ID for old CB750 836 K1

[mycb750k6]

Pool man gave me his CB750 K1. I pulled the head and pistons out and the pistons measure 65.5~ and have the initials RCW or ROW embossed on the inside and the pins have nylon caps instead of circlips. Anybody guess at the brand of these pistons? This is an old 71 so the work was likely done eons ago. Just curious as to what kind of prize I may have had handed to me.

[Jerry Rxman Griffin aka MuthaF'er]

Myles,

Can you post a picture?

[mycb750k6]

They are stamped ROW or POW or RCW or something like that on the inside of the piston. Can't really tell.  - Anyone?
They appear to be high compression with the raised dome. Also the pins have nylon keepers. This motor also has a 15 tooth front sprocket.

[Big Jay]

They are a cast piston. Do they have 3 piece oil rings?

[mycb750k6]

no, they are the old style one piece oil rings,

[Howell]

They are stamped ROW or POW or RCW or something like that on the inside of the piston. Can't really tell.  - Anyone?
They appear to be high compression with the raised dome. Also the pins have nylon keepers. This motor also has a 15 tooth front sprocket.

If it is POW then it is maybe Powroll , I had Powroll pistons in my CB450 racer with those nylon keepers.
http://www.powroll.com/

[MCRider]

They are stamped ROW or POW or RCW or something like that on the inside of the piston. Can't really tell.  - Anyone?
They appear to be high compression with the raised dome. Also the pins have nylon keepers. This motor also has a 15 tooth front sprocket.

If it is POW then it is maybe Powroll , I had Powroll pistons in my CB450 racer with those nylon keepers.
http://www.powroll.com/

Beat me to it. I'd vote for Powroll. I had an 888cc Powroll kit in my CB750, lasted a long time. But upon disassembly I realize they were real low tech pistons, cast, heavy, but functional. Powroll discontinued CB750 stuff long time ago.

Still in thriving business with their first love, single cylinder four strokes. I had a 102cc Powroll piston in my CT90.

[mycb750k6]

thx MC. Calcs indicate 855cc is there was such a thing. Thought I had winner here for a moment. Oh well.

[MCRider]

thx MC. Calcs indicate 855cc is there was such a thing. Thought I had winner here for a moment. Oh well.

This calculator puts it at 850cc nearly exact. Must be what CycleX is selling as well, at the limit of the stock cylinder sleeve. You'll need to resleeve that block to use it, probably. Or maybe the CycleX pistons would still fit if its not worn too badly.
http://www.nightrider.com/biketech/calc_displacement.htm