Hi. My bike is a 96 model with 21k on the clock, as i gradually increase the revs at a standstill it seems rough untill about 5000 then rapidly leaps up to max like its just hit its power band. When riding it also feels rough in that rev range but when twisting the throttle it pulls like a train and feels great.

I have replaced all spark plugs, an ignition coil(suspected problem), stripped the carbs cleaning all jets and adjusting pilot screws and visually checking all the butterflys are in the same position(no vacumn guages) and float bowls also in the same position (sounded so confusing checking them didnt bother)

Bike does have a scorpion can on so im wondering if that could be a problem ?

I have adjusted & checked the EXUP valve that seems fine.

So any ideas please ?

could it be worn emulsion tubes in the carbs?

Worn Emulsion tubes?? maybe can i tell by looking at them ? Tks

yes I understand the needles will wear them oval in time and thus cause enriched fuel supply with low revs part throttle opening, not talking from experience though...