Surging at Full Throttle

If it was my bike, since it has a stock airbox and exhaust, I would simply install the stock jets and needles with everything in the stock position. There's no doubt in my mind that the engine ran fine when everything was stock and the bike was new, so stock jets, etc. should still work fine. If not, I would suspect the problem is elsewhere. Ed

Raising the needle is not rejetting. The bikes of the late 1970s and 1980s cam e set up as lean as possible from the factory to appease the EPA. As long as everything was up to snuff, the bikes ran just fine. However, even a little change like a low restriction air filter could introduce very slight lean surge in some bikes. The easy solution is to raise the needle just a scosh to fatten up the mid-range. Other folks did this thinking there was hidden horsepower to be unleashed this way. As 650Ed said, on a stock bike in a good state of tune, there is really no need to raise the needle, much less to rejet the carbs.
What problem are you trying to solve?

Typically changing the needle position is for altitude changes unless they are CV carbs. They are more tolerant of this. If you have this issue, it might be old dried out diaphragms. When they get hard or are leaking they don't operate as intended and raising the needles could compensate for this to a point. I'd check them first.
Steve

Thanks for the suggestions. I do not have the diaphragm carbs I have the slides I believe they are the VM carbs. The problem I am trying to solve is that my bike is maxing out at around 95mph and 3/4 to full throttle causes the bike to lose power intermittently and surge. I know someone had mentioned the throttle stop screw could be the cause of this? I will try returning the carbs to stock to see if that addresses the problem.

Check the spark advance that it moves freely.
Steve

Thanks, and sorry for the stupid question but is that done just by turning the 17mm nut under the points cover, or will I need to take off the points? I'll reference my manual in a couple minutes

Take off the points plate, remove the 13mm bolt in the center of the "nut" and pull off the spark advance. Clean and lubricate it so it moves freely being sure the springs aren't loose or broken. Put it back together. Retime it.
Steve

great thank u!

Finally got around to getting the spark advance out of the bike. It moves freely but one of the springs does seem to be a little loose. Is it time to find new springs/replace the ignition advance ? Would a spring being slightly loose effect the performance of my bike at higher revs?

Once you get past a pretty low RPM threshold, the advance is usually at the maximum advance straight through redline. A weak spring would only affect low RPM and idle.

High ethanol content in the fuel can cause a lean running issue if jetting is on the lean side to start with.