Topic: CB550 cam and rocker specs (cross post)

[Scott S]

 I posted this question in the SOHC4 forum, so forgive the cross posting, but I was wondering if maybe some of you Hi-Po guys might have the specs?
 I've searched a LOT and can't find them. Anyway, here's a cut and paste:

Here's what I HAVE found:

SPECS:
 
 Stock (1974) CB550 cam
 
1.36 exh.       lobe              1.38 in.
1.110           base circle       1.110
0.252              lift              0.272
 
CB650 cam
 
1.39 exh.       lobe               1.40 in.
1.110            base circle       1.110
0.280             lift                0.293
 
 Can anyone give me the duration?
 What ratio are the rocker arms?
 Are the CB550 and CB650 durations the same?

[Bill/BentON Racing]

Stock CB500/550 cam intake duration 240 ex 245.Intake lift .300 ex .280.Hope it helps...try and find a Yosh B grind or similar. My .02. Bill

[Scott S]

 Is that lift at the valve? Is that taking the rocker arm ratio into effect?

 Why do the specs I have show .272 vs. .300 on the ontake and .252 vs. .280 on the exhaust? If it's because of the rockers, that will make it easy for me to find the rocker arm ratio....

[Bill/BentON Racing]

Specs out of 1980 Action Fours catalog.Doesn't say how they measured.Bill

[Scott S]

 If I divide the lifts you listed by the ones I have, I come up with a 1.10 or 1.11 rocker ratio. Sound reasonable?

 Does that mean the CB650 cam has .322 intake and .308 lift at the cam?

[Scott S]

 And, Bellcow, does the catalog list anything for the CB650 cam?