Induction whine normal?

[Gnarbunkle]

Have 2nd inlet cam on exhaust, deg at 105/105. I notice a weird induction whine (not loud) a bit like a belt driven supercharger, that comes on at about 1500rpm at light throttle (in neutral) airbox off at time. Any ideas why? safe to run?

[Gnarbunkle]

False alarm, turned out to be starter motor O-ring not seated correctly in groove, pair crankcase suction caused O-ring to vibrate like a reed! cool sound just like a belt driven superharger! but no vacuum in crankcase so I greased and reseated the crank cover and problem solved.