Engine differences between CB77 and CA77

[Geoff Hastings]

Hi guys, I just bought a spare CA77 engine which is complete except for the outer cases and everything that you would normally find inside those cases. The rotor, stator and starter clutch are there so I'm looking to build a complete engine to swop with my worn one at some stage in the future. My question is, are most of the similar age CB and CA parts interchangeable ie outer cases, clutch, kick starter, primary drive etc. Thanks a lot Geoff.

[G-Man]

Geoff

Quite a lot of dfferences:

Starter motor and starter clutch the same.

Cranks are different. C and CA are 360 degree firing interval. CB is 180 degree. CA crank webs are larger diameter. Oil pumps are the same

CB and CA gears and gear ratios are the different but the complete transmission is interchangeable.

Cylinder head, cam. pistons are all different. CB has dual points, CA single.... Advance retard unit and sprocket are different.

Barrels the same.

Primary drive, clutch and clutch cover are the same.

Kickstart outer covers and kickstart different.

G

Hi guys, I just bought a spare CA77 engine which is complete except for the outer cases and everything that you would normally find inside those cases. The rotor, stator and starter clutch are there so I'm looking to build a complete engine to swop with my worn one at some stage in the future. My question is, are most of the similar age CB and CA parts interchangeable ie outer cases, clutch, kick starter, primary drive etc. Thanks a lot Geoff.

[Geoff Hastings]

Cheers Graham, that will help me sourcing parts as the CB parts seem to be more common.