Topic: CB650 cam into CB500 motor

[triple]

Hi all, I know this will be on the forum SOMEWHERE but don't have time to search hence the need for assistance.

I have read that the CB650/4 cam is a good alternative for the stock CB500/4 cam.

My questions regarding this are as follows

Is there any model / year CB650) cam that is the preferred item ?
What year do the 650 cams run from / to
Is it worth doing the change ( i.e power gains etc ) anyone got performance no,s ??

any other things I need to take into consideration ?


thanks in advance to all that respond.

[DaveBarbier]

If you read through these you'll get a good understanding of what has to be done. As far as actual numbers of power gains, maybe someone can comment.

https://www.google.com/search?q=sohc4+650+cam+500&ie=UTF-8&oe=UTF-8&hl=en-us&client=safari#q=sohc4+650+cam+500+site:forums.sohc4.net&hl=en-us&prmd=smivn

[mrfish2]

Is it worth doing the change ( i.e power gains etc ) anyone got performance no,s ??

I can comment on the performance gains, but for a 550, not a 500. The 650 cam will bring out the mid-range power a little, or that's at least what my butt dyno told me. As far as horsepower I'd say it'll add maybe 2 over stock, but you'll definitely feel the difference. My 550 put 37hp to the wheel with a 650 cam and MotoGP Werks exhaust.

[Restoration Fan]

that's at least what my butt dyno told me.

My 550 put 37hp to the wheel with a 650 cam and MotoGP Werks exhaust.

Pretty exacting measurements for a butt dyno.  Well done! 

[mrfish2]

My 550 put 37hp to the wheel with a 650 cam and MotoGP Werks exhaust.

37RWHP is about dead stock for these bikes. 50BHP is stock claimed.

That's why I say it only adds maybe 2, if any at all. The 650 cams have the same amount of lift, but longer duration, correct?

[buffalogt750]

My 550 put 37hp to the wheel with a 650 cam and MotoGP Werks exhaust.

37RWHP is about dead stock for these bikes. 50BHP is stock claimed.

That's why I say it only adds maybe 2, if any at all. The 650 cams have the same amount of lift, but longer duration, correct?

I thought the 650 cam had .030" more lift as well as a little more duration

[flatlander]

there's a thread here with some comparison data: http://forums.sohc4.net/index.php/topic,134461.0.html

i didn't try a 650 cam myself but i'd expect that it adds a little torque for better midrange and does pretty much nothing for top-end hp.
so... it's a "good alternative" if you have one lying around and want a bit better acceleration, and don't expect any dramatic improvements.

[triple]

Thanks to all that replied , I  was aware of the sprocket swaps and tach drive , lobe clearance etc but was not sure if it was a worthwhile proposition.

Got a lot of links which provided good reading from people who had done the change themselves.

Thanks again fellas.

[flatlander]

there should not be any clearance problems, the 650 cam is nothing radical. but of course you should check to be safe.