Topic: CB650: engine swap with other SOHC4's?

[problemaddict]

Hi there,

I recently purchased an '81 CB650 for the whopping sum of $50.  I'm looking to build it into a commuter with an emphasis on mpg.

The problem is that the motor is stuck.  It will spin, but only about 180* before it sticks in either direction.  Instead of getting into rebuilding this engine, i'm interested in swapping in another engine that is known to be in running condition.

My question is this:  are there other SOHC4 engines that are dimensionally similar with the same motor mounts as the CB650 that will swap into this bike relatively easily.  ie. the 450,500,550, and 750 motors.  If so, that will greatly increase the pool of running parts bikes i can search for.

thanks for any help!

-Mike

[bryanj]

500/550 will fit direct as long as you use the appropriate coils, carbs and ignition system for the engine. 550 has better clutch

[MJL]

The 750 is physically larger and won't fit in the 650 frame. the 650's cylinders are more or less vertical and the 750's cylinders lean forward.

IIRC the 500/500 has the same case but smaller cylinders, you may be able to swap the 650 cylinders and cam over to the 500 case.

[Hush]

Puts hand up for the carbs!
Nah seriously I'd hunt another CB650 motor or even better have a wee looksee to find out what is jamming.
Heck it only cost $50 what's the harm?
I'll take the exhausts too.........