advancing the camshaft makes more torque acceleration, retarding the cam makes more top end HP.....supposedly.
One thing for sure Ive never had any success with retarding the cam timing and would avoid it like the plague.
With such a long cam chain connecting the crank to the camshaft, centrifical force makes the chain rollers move up higher on the sprocket teeth which retards the valve timing greatly.
I used to think the cam manufacturer would have built some compensation into the grind but I have spoken to two cam grinders in OZ about it and they both said " the chain is your problem not ours"
So the good oil for the hi revving, long chained overhead cams is always advance the the camshaft , running them straight up or retarding makes them accelerate like old dogs and even though the retarded theory is more top speed any experiments I done on any Honda engine retarding made them slower both access and
top end.
I once had a play with cam timing on a little Honda Z50, put in a hot cam and tried the cam position from 10 deg adv, 5 deg adv, 2 deg adv, 0. then 5 deg retard, 10 retard.
Result was advancing made it easy starting, good accell, Evan a wheel stand
Retarding , hard starting, slow accell and slow top speed, at 10 deg retard I had to run along side and push like #$%* to get the bike to Evan go.
Eventually the cam placement becomes a big player in racing engines and can be used to compensate for gear ratios, track condition, average corner radius, fuel consumption, tyre compounds and stuff like that.
In my world If your sealing up the HP motor for a while ie road bike I always go 1 to 3 deg advanced, stock I would go 3 deg cos the chain wears like #$%* with milage.