Motorcycle Repair: acceleration / rev limiter ???, high tension wires, bobby martinez

Question
My ride is a 1996 Honda Shadow VLX600.  I just bought it and is in the process of conditioning the bike. The only modification that I noticed is that exhaust had been replaced to free flow and carbs rejet (a little bigger main jets).

My problem is as follows:

1) When I accelerate during 1st, 2nd, 3rd, and 4th gear, it seems that the engine won't further give any more power after reaching high rpm (sort of a rpm limiter?).

Feels that the electrical system is limiting the current and won't accelerate?  At high speed, say 65mph and going faster, it will suddenly stop accelerating for around 4 seconds and then power up again, and happens routine.

My suspects are as follows:

1) Air filter (removed but still the same)
2) Replace High tension wires for spark plugs
3) Adjustment of Carb pilot screws
4) Re-jetting of main jets

I don't want to do a trial and error as this would be expensive replacing each component.

Please, i need your expert advise. thanks a lot in advance.

Regards,
robert
bobby.martinez@innove.com.ph  

Answer
Hi Robert,

If you're revving the engine to redline, it's into the rev limiter. If the symptoms occur before redline, and at same throttle opening positions, suspect a carburetion tuning issue. That's the best I can offer with the information provided.

Learn to read the spark plugs. They'll tell you what is happening by their appearance.

I'll send some tech files to your email address. These files may help you diagnose and correct the problem.

Respectfully,
Mark Shively