Topic: Cam identification

[Don68]

I bought a trailer load of parts from a gentleman getting out of the hobby because of health issues.
I would like to put a K model cam in a CB750A I have. I do I identify the K model cam? I do not know if the cams I have are from a F model or a K model.

[754]

Mic them they would be miced anyway..

[Don68]

When you say mic them, are you talking about the lift?

Do you know the lift of each cam?

[bryanj]

Cam specs will be in the Honda workshop manual

[754]

Lift which is 2 measurements, and journal size.  Not sure what A uses, but it should be less than a K . Late F are visibly fatter lobes.

[HondaMan]

A coarse method would be to use calipers (like the cheap Harbor Freight ones, they might last long enough?). The lift on the "F" engines is usually 8.0mm, give or take 0.5mm. The lift on the K cams are about 7.8mm intake, 7.6-7.7mm exhaust side. The lift on the A cam is less, like 7.6mm intake and 7.5mm exhaust. The "A" cams open very late in the intake lobes, about 5 degrees AFTER TDC, but this is hard to measure outside of having them in an engine. The K cams open a few degrees BEFORE TDC, and the F cams open right on TDC.

[PeWe]

One cam is easy  to identify.
K7 and F used this, maybe K8 too. (Not F2)
There is a ring beside the tacho gear.
https://www.cmsnl.com/honda-cb750k7-four-england_model14390/cam-shaft_14101392000/#.XklIB2RwGKo

[Jerry Rxman Griffin aka MuthaF'er]

IMO just use the biggest one you have. There is difference but not like an after market hot cam.

[seanbarney41]

IMO just use the biggest one you have. There is difference but not like an after market hot cam.

+1, the performance differences between models is only very slightly affected by the different grinds that came in different years and models of cb750's....what I am trying to say is there were several very slight engine tuning changes that added up to bigger differences and cam grind changes were just one of several.  The difference between k and f cams is very slight and unlikely to be perceptible to the butt dyno.