Topic: need to I.D. several unknown, CB750 cams -- several questions and pics.

[fang]

So I stayed up last night and dug out several boxes of old performance parts.  I found three unknown cams, all of which were put in the box because for one reason or another I thought they were aftermarket... but that was about a decade ago.  I am not seeing identifying marks, so God only knows whether I even had them sorted correctly at the time.  I can only barely remember stashing them away.

I have one quick question about measuring:  My automotive cams are frequently measured at 0.050".  It seems motorcycle stuff is usually measured at 0.40", and I know that some of the aftermarket CB cams were measured at actual valve lash (making them look 'bigger' than they really were....

I am planning on measuring at 0.040"  HOWEVER, Since I am trying to reproduce numbers to help me ID these old turds, what is the general consensus for finding matching numbers?






Thanks!
-Steve

[754]

 For starter post the lobe diameters. and any marks on the ends or engraved between the lobes. Is the top one Grey coated? Norris used the coating and, and marked grind on a flat spot between the. Lobes.
 We had one here marked Luther, never saw that again..

[fang]

754, none of the cams are coated. 
I thought I could measure lobe duration with the degree wheel on the cam -- simply record the degrees *2, measured at 0.04" before and after "zero", but my numbers we so different from what I expected, I now am doubting them.  I went ahead and posted those too.  Having said all that I am super tired, and likely made some obvious error.

Cam #1 -- marked (stamped) "R1" -- this was purchased as a big bore/race cam, possibly a Megacycle.
Intake lift    0.338"
Exhaust lift 0.333"
In/Ex lobe duration 220° - @ 0.040"

Cam #2 -- marked (stamped) "R2" - completely unknown. 
Intake lift    0.300"
Exhaust lift 0.383"
In/Ex lobe duration 190° - @ 0.040"

Cam #3 -- Marked RC315 - Russ Collins ' Hot Racer Cam' (LINK) - this cam felt like it will require a little lateral-play lobe clearing.
Intake lift    0.365"
Exhaust lift 0.365"
In/Ex lobe duration 260° - @ 0.040"
In/Ex lobe duration 460° - actual from "zero"

I'll take another look at these a little later.... I also might try to check some stock cams to compare my measuring to their known numbers.

peace and grease,
-Steve

[754]

 Do you want to sell the 315?
 PM me if you do..

[Bill/BentON Racing]

That's the correct lift on the 315! Frank........you can't have them all!!!! Bill