A couple of tuning questions

[znen13]

1.  For a stock 49cc 139qmb, what are the maximum safe RPMS (both peak, and sustained)?  I have seen conflicting information on this.  Currently my setup will wind up to about 8700 RPM briefly at WOT acceleration, but for most of the acceleration pull it is around 7500 and drops to 7150 as speed increases.  I am considering using some lighter rollers to increase the average RPM a bit as the engine feels a bit stronger in the 8000-8500 range.  

2.  Pilot jet selection:  if the engine idles well and rpms peak at a mixture screw setting of 1.5-2 turns from seated, is there any reason to change the pilot jet?  Will pilot jet have any influence on the first second or two of acceleration?

3.  Accelerator pump:  is the pump a factor in soft initial acceleration?

[GrumpyUnk]

#3: The accelerator pump squirts a jot of fuel into the ventrui when working. It prevents a stumble/stall due to the intake air moving NOW, because it is less dense than the liquid fuel trying to get pulled out of the carb passages/jets/etc, which would cause a momentary lean condition.
If it accelerates without stumble or hesitation, it is likely working. If set improperly, it can deliver late or fail to deliver any liquid fuel at all.

tom