I am trying to dial in a CB2239 for an 1600 I am building, however the cam events don't seem to be quoted at .050". From the cam cam image below, any idea what checking clearance I should measure at? It says "running clearance" of .004/.006" but I assume that's the valve clearance (although I might try checking at those clearances today). I tried testing at .000" but it is just too hard to get a reliable measurement.
I don't know what checking clearance CB uses to generate those numbers, but it's obviously not .050". We've got some resident experts on CB cams, you should see an intelligent answer soon...my best guess is that they use .004/006" lash and note the crankshaft degrees just as the valve leaves/sets down on the seat.
It looks as though the timing is OK, probably around 1° advanced.
Your numbers yield 240/233° duration @.050" (spec is 234°). The .417" lift is at the valve with 1.1:1 rockers, which coincides with a lobe lift of .379-380".
CB cams are on 107° lobe centers, which theoretically will make the torque peak a little higher and earlier than the 108° used by Engle...but I doubt that anyone could tell the difference by the seat of their pants between this and a W-100.
I know this is a bit late but I'm currently building a type 4 motor with a cb 2202 cam. went to check the cam timing out and dial the cam in and ran into the same issue. after playing around with it for a few hours I discovered that if you measure it a 0.025" lift it seems to follow the cam card. why they would check and 0.025" lift I have no idea but that seems to be the case.
