Jets
Hello Phil. Sure sounds like you got stock jetting and a dirty filter.
Service entire bike, double check zero leaks anywhere on that expensive pipe, especially at exhaust ports.
Ensure muffler is fully repacked or whatever those need. Hot tip: loosen every frame and pipe bolt on whole bike, except exhaust ports. Warm bike fully. Park on level frame stand. Let cool for a day. Starting closest to crank shaft and working outwards, torque every bolt properly. If a bracket is pulled in or has a gap, bend or shim it first. Guess what, now your bike is much straighter and smoother. This works on every bike, and was invented by one Pierre Deroches decades ago while making the fastest race bikes around.
Now, ride bike for a good 20 mins. Only then try the following:
Ride in 4th gear. Dial throttle to wide open then smoothly roll it closed. If bike accelerates as you close throttle, main jet is to lean, go up one size. Repeat test until bike only slows as you close throttle. Done there.
Look at jet needle. Clip has to be in middle position. Ride for 20 mins. Now, ride along in 3rd gear at 1/4 throttle. Snap throttle open only to 2/3 and hold there. If bike bogs it`s too lean, move clip one notch down. (raising needle) Repeat test until bike responds instantly, with big power. Done there.
Sorry, do this step FIRST. Pull petcocks and pilot jet. Both are blocked. When spotless reapply. Set float level to stock specs, it is wrong now. Start bike, let warm. Air screw is already at 1.5 turns out, right? Adjust idle so it seems a tad fast. Now slowly turn air screw out till idle goes up. Turn idle down a tad. Turn air screw out a tiny amount more. Adjust idle again, leave it a bit fast. You are done! This ordeal is exactly what every tuner has done for ever. Yes it`s hell on multi cylinder bikes.
Go blasting on your smooth fast racer. Now go faster. Fun isn`t it? L
