low power before 4k rpms

[lowandslow_A4]

Hey folks, still trying to figure things out on this bike and was wondering if its normal to have low power before 4k rpms and after it just takes off. just a weird flat spot.
also, whats the top speed you guys would recommend cruising at. im already at 6k rpms at roughly 60mph.
Thanks for any help!

[Rikugun]

My guess would be various aspects of carb issues. Clogged/dirty low speed jets, emulsion tubes, and associated passages would be a good place to start. If not done already, disconnect the YICS and plug off the engine vacuum ports as a diagnostic check and note any improvement. Check for other vacuum leaks in the normal fashion. I'm assuming the air box has a functioning flapper installed.

Also suspect under performing/mal adjusted accelerator pump. Without the proper volume and  instantaneous stream of fuel with throttle opening, the engine will fall on it's face. Finally check/adjust idle mixture and carb sync.

[QBS]

Regarding, top cruising speed:  My '83 has zero problem sustaining 85mph two up and heavily loaded for touring/camping as long as there is gas in the tank.  One up, unloaded: 90mph is upper comfort zone for me.  The bike could probably do a sustained 95mph if the rider could handle the wind and various vibrations.

This type of capability is what makes the V a great sport touring bike.