cb77 cylinders/barrels

honda brian · Post by **honda brian** » Tue Mar 09, 2010 5:15 pm

G'day men of knowledge.
Can you help me with a with a possible problem. I have a cb77 crankcase assembly (cb77e-213496), and I need to know which cylinders/barrels to use on this. I seem to remember reading a thread concerning holes in cylinders or oil supply but can't find it. Did I imagine it?
I have four cylinders/barrels to chose from,so hopefully have one to suit.
Thanks chaps.
Brian.

CliffC · Post by **CliffC** » Tue Mar 09, 2010 6:13 pm

Hi Brian,
The case you have is the 305cc CB77. I cannot remember if the cylinder says 305 on the lower front for the 305 cylinder or not but I do know that the 250cc CB72 will say 247 on the lower front and the numerals will be raised. Both cylinders will work on your case. Hope this helps, Cliff

davomoto · Post by **davomoto** » Tue Mar 09, 2010 7:39 pm

Ther are 8 and 9 hole cylinders. The early ones had only 8 holes, the 9th was added for the oil to drain down from the top end. You have to check the top engine case, and see if it has the oil passage or not, and then the cylinders as well. Hope that helps!

davomoto

honda brian · Post by **honda brian** » Tue Mar 09, 2010 7:44 pm

Thanks Cliff, I know about the differences as far as CB77/CB72 is concerned. I need to know if there are any differences between early (1962) CB77/CB72 cylinder/ barrels/jugs and late (1966) model cylinder/barrels/jugs, apart from 60mm versus 54mm bore size. I seem to remember a thread about oil holes. Sorry for not making myself clear.
Brian.

honda brian · Post by **honda brian** » Tue Mar 09, 2010 7:55 pm

Thanks Davmoto, I just checked my barrel supply and one has 8 holes, the rest have 9. Never noticed that before. As usual, go to the experts. Many thanks to all.
Brian.

teazer · Post by **teazer** » Wed Mar 10, 2010 12:00 am

It's not all that important to the discussion, but that the extra oil hole in the front is to feed oil up to the top end from close to the center rather than from the left end. In theory it balances the flow up the left and right outer front studs, rather than feeding it all from the left front stud into the front oil cavity.

presumably the earlier ones tended to leave teh right side short of oil.

All the oil drains down through the cam chain chamber.

And of course there are wide and narrow cam chain tensioners, but I'n not sure which is which - early or late.

CliffC · Post by **CliffC** » Wed Mar 10, 2010 3:19 pm

Hi Brian,
Sorry about that, I misread what you were asking for. I'm glad you got the info you needed. Cliff