Cylinder barrels CB77/CL77

[Dean]

Are the cylinder barrels interchangeable between the CB and CL models and between all years. I am asking as I have been offered NOS CB77 barrels ( part number CB725166 6) for using on my CL77 racer and need to be certain as the seller is 2000 miles away!!

[georGe]

The part number you posted has a cb72 prefix which indicates they are for a 250cc not a 305cc !! There is a 6mm inside dia. and 4mm outside dia. difference between the two.<br /><br />georGe

[Lee]

<br />Are the cylinder barrels interchangeable between the CB and CL models and between all years. I am asking as I have been offered NOS CB77 barrels ( part number CB725166 6) for using on my CL77 racer and need to be certain as the seller is 2000 miles away!! <br />

<br /><br />Yes, while it has been around 40 years since I worked with CB-77 &amp; CL-77 cylinders, I'm as sure as I can be that they are all the same for all years. I would go ahead and buy them.

[Dean]

Thanks for the info.<br />The barrels were for sale on Ebay until yesterday and the final bidder paid £150. Over double what I was prepared to pay. Now I will just get the barrels rebored and fit oversize pistons, maybe high compression type.

[Lee]

<br />Thanks for the info.<br />The barrels were for sale on Ebay until yesterday and the final bidder paid £150. Over double what I was prepared to pay. Now I will just get the barrels rebored and fit oversize pistons, maybe high compression type.<br />

<br /><br />My advise is to get the next size oversize pistons (0.010&quot; / 0.25mm) and bore to 0.002&quot; clearance. Then make sure each piston ring has the proper end gap (0.010&quot; I think). I would not get higher compression pistons unless you want to get a solid copper head gasket and run very high octane gas; the pistons will most likely ping on premimum gas at low RPM. If you want to go to 350cc you may be able to get Hepolite sleeves and pistons. I believe the sleeves require a 0.002&quot; press fit; a tourch or oven would be required to remove and replace the sleeves, and naturally the aluminum cyclinders would have to be bored out to accept the larger sleeves.

[georGe]

150 Brit Sterling isnt that bad if they were in fact CB-72(250cc) cylinder/sleeves, definitly would not pay that much for CB/CL-77(305) cyl/sleeves. You can get sleeves from L.A. Sleeve for around $40 USD a piece and then have a machine shop do the finish work. <br /><br />georGe