Piston rings for 1964 CB77 with big bore kit

Donjp · Post by **Donjp** » Fri Feb 27, 2009 4:31 pm

I have had since new a 1964 CB77 305. In the later 60's Webco Forged True offered a 350 kit for this bike. It included cylinder liners, high compression pistons and gaskets. I purchased this and ran it for a number of years. The bike has been off the road for a lot of years and I would like to restore it. I need to find new piston rings. I contacted JE Pistons and Wiseco with no success. Does anyone know where I might get a set of rings?

rbaselt · Post by **rbaselt** » Sat Feb 28, 2009 7:56 am

You might try Mike at Engine Dynamics in Petaluma, CA <http://www.enginedynamics.com/>. Give him a call with the piston diameter and ring thicknesses. If no luck, send me a PM, I have a couple other sources. --Randall

rbaselt · Post by **rbaselt** » Sat Feb 28, 2009 7:56 am

You might try Mike at Engine Dynamics in Petaluma, CA <http://www.enginedynamics.com/>. Give him a call with the piston diameter and ring thicknesses. If no luck, send me a PM, I have a couple other sources. --Randall

wombat200 · Post by **wombat200** » Mon Aug 03, 2009 5:46 pm

What are you intending to do about the liners - have some made up?? If so, do you have specs?

Donjp · Post by **Donjp** » Mon Aug 03, 2009 6:50 pm

I still have the original liners and they are in good shape. I am just hoping to get new piston rings but so far no luck. One of the places suggested I send them my pistons but I am a bit reluctant to do that.

wombat200 · Post by **wombat200** » Mon Aug 03, 2009 8:01 pm

Well, the Piston company that I use in South Australia also supplies rings - they would require the pistons & hopefully the old ring, in order to supply new ones....... I understand your hesitation, but sometimes there is no option.....

I'd love to know the sizes on your liners, particularly the outer diameter & if they are stepped or not?

Donjp · Post by **Donjp** » Mon Aug 03, 2009 11:24 pm

I have attached a couple of pictures of one of the pistons. The top ring is a "Dykes" style ring. I have also done some measuring of the piston and I include this here.

OD of the piston on the skirt - 2.516"
OD of the piston where the rings are - 2.506"

Overall height of the top groove - .065"
Height of the inner groove for the top ring - .031"
Depth of top groove - .125"

Height of 2nd ring groove - .06"
Depth of 2nd ring groove - .125"

Height of 3rd ring groove - .11"
Depth of 3rd ring groove - .125"
I may be able to measure the liners tomorrow. I would only be able to measure the bore and the OD of the liner at the bottom as they are pressed into the cylinder casting. Not sure if there is a step.
Don