cbr600F3/F4 interchangability?

[91lxcoupe28]

I have a friend with a 99 cbr 600 F4 that needs a motor... We have been having a hell of a time finding one for a F4. We have run across a few F3 engines in good shape, what are the chances that an F3 600 will bold into an F4 bike w/ minor or no mods?

[stunter bob]

o anything will fit....but i think the front motormounts have to be moved forward on that one if you do that swap
your better off finding an F4i motor with the complete harness and just converting the bike to FI instead of the old carbed F3 junk

[futant]

I like F2/F3's myself , but I agree with stunna bob.
There's no reason to go to carbed , it's more problematic , and would require custom mounts etc.
The engine would be cheaper and all , but I would think you can find a F4 motor pretty easily also.
Too much work for no benefit.

BTW , there is zero chance it will just 'bolt right up' ;)

[HobieF3]

BTW , there is zero chance it will just 'bolt right up' ;)

Yeah, they're similar, but not that close. I've known people to put F4i motors in F3's, but not the other way around.

The F4 was only produced for two years and there are far fewer motors available than say an F4i motor.

Have you looked into swapping the F4i long block? Physically they are identical in terms of size and attachment points. The only difference I'm aware of is a sensor in the head of the F4i that's for the FI that's not in the F4 head.

You can find F4i motors for as little as $600 shipped if you look. Absolutely NO WAY I would pay more than $1200 shipped.

[91lxcoupe28]

Yeah, they're similar, but not that close. I've known people to put F4i motors in F3's, but not the other way around.

The F4 was only produced for two years and there are far fewer motors available than say an F4i motor.

Have you looked into swapping the F4i long block? Physically they are identical in terms of size and attachment points. The only difference I'm aware of is a sensor in the head of the F4i that's for the FI that's not in the F4 head.

You can find F4i motors for as little as $600 shipped if you look. Absolutely NO WAY I would pay more than $1200 shipped.


I think thats what we are gonna end up doing...


thank you all for the help

[91lxcoupe28]

ended up picking up an F4I engine, swapped the 2 covers, and viola! have a running, F4 with a carbed F4I engine. Thanks for the info!