My 500 quit surging when I got the idle screw backed out to a useable position. When I bought the bike it was worn-out and the throttle cable was tightened in the adjusters to get it to idle. I didn't know that right away, but I did notice that the idle adjustment did nothing. That was because the seals were worn and so was the cylinder. The slide slamming closed completely is what you want for less surging. Jetting can get you to idle as long as the seals are tight.
Also, the surging will only get you into trouble, if you forget to grab the clutch.
On another note, I recently discovered that floats set too high(to shut-off the gas later) robs lots of power and causes a rich condition that is impossible to jet- out completely. Getting the floats set perfect, and being absolutely positive the reeds are sealed ( resisiting raw fuel) makes it rev hard. A few times we have tinkered on the jetting or float level and actually somehow caused the floats to stick or not get it back right. Keep an eye on overflows when having these issues. Fuel pouring out is a stuck float which is easily fixed. Make sure the flow of air is as free as possible, i.e clean filter, clean functioning powervalves, clear silencer.
