[mpower]

Hi everyone,

New to the forums and new to the CB450's as well. I was doing some research on the interchangeability of the engine on a CB450 and stumbled on this site. Lots of information here but unfortunately, I was not able to find the answers I need. I hope you all would be able to help.

I just picked up a 1971 CB450K4 and realized that that the engine serial number belongs to a 1968 CL450K1. I read that the CB450 and the CL450 is pretty much the same bike so I assumed that it is fine since it bolts right up and fits OK. I was curious if there was much difference in the motor from a 1968 versus a 1971. Should I be concerned at all?

Thanks in advance for your help.

Regards,
John

 

[tbpmusic]

No concerns whatsoever.
All 5-speed 450's are essentially the same engine, whether CB or CL.
Later K models had slightly different cams, maybe a chain oiler thingy, but pretty much the same.
You may just have the upper crankcase from a CL, or maybe a complete CL engine - no matter........

Further, the only differences between CB and CL are cosmetic, for the most part. Different forks/front wheel, mufflers, tank/seat, handlebars.

 

[66Sprint]

Nope, the 5-speed CB and CL engines are 99% internally identical..... (with minor variations possible in the countershaft that are relatively inconsequential).... The swap should cause no problems......

 

[mpower]

Thank you for the replies! Good to know that there isn't a interchangeability problem when I go to fix this thing up.

Regards,
John