I looked at an old RC cam installation guide for this info.
(1) Do not shim stock springs more than .045"
(2) Coil bind - check between rocker and cam, .050"
(3) Intake valve to piston clearance .050"
(4) Exhaust valve to piston clearance .080"
(5) 1 degree cam advance = .020" more exhaust valve to piston clearance.
Now the F-2 cam question.
My old notes show this to be .318" intake, .302" exhaust lift. I assume I took these figures at the valve @ .040" lift, zero lash, but for some reason didn't write THAT part down, so these numbers are for refrence only.
The F-2 Honda Service Manual shows @ .040" lift, the opening and closing numbers (I= 5-40, E= 40-5) make this to be 225 degrees duration, both intake and exhaust, lobe centers 107.5, overlap of 10 degrees.
Compared to the K8 cam figures of 220 duration, LC 110, overlap O, the F-2 should flow a little better mid to top end.
Now, a look thru an old Megacycle book has them listing stock K/F as Int - .315" 220 dur, Exh - .313" 235 dur.
Hmmm...
With this in mind, it seems a good idea to 'practice degree' your existing cam and look at the actual numbers. You may find there's not a lot of benefit to the swap.
Unless you pick up more valve overlap, you won't get the additional higher RPM cylinder charge filling. Generally a cam with 104 lobe centers has more overlap than one with 110.
As far as lift goes, unless you have some radical mods done to the intake ports, the flow increases really slow after about .350". That's not to say some porting shops can't make it happen, but the cfm flow difference between .350" and .400" valve lift isn't as much as you'd think.
For what it's worth, my experience is that with no other changes, an F-2 with it's cam degreed @ 102 LC (intake) would really pull at low revs, but had no 8000 rpm power. This was great for the 260 pound guy that was riding it to work every day, I imagine that closing the valves early gave it more cylinder pressure which accounted for the additional low end torque. He loved it, but that motor never saw redline.
When degreed @ 107 my stock F-2 would run 101mph in the 1/4 mile, and over 110mph WOT.
If you degree your cam and don't get the numbers you want, just CAREFULLY slot the sprocket a little. It won't slip after torquing.
And
If anyone's interested, I can send you the scanned-in degreeing instructions.
When I looked in the TECH forums, I didn't find anything like these.
