@5twins id like to confirm some speculation before I start dumping money:
1: The 4n8's required a z6 short needle jet, are the z8's the same? since short z6's are hard to get
2: Since the 4n8's and the 502's are nearly identical besides the 5mm difference in height, id be curious to see if that 5mm extra is due to that spring and extra fluff they added on the later slides? Theoretically a 4n8 with '75 model slide should react the same as a 502 on the newer model slide?
3. If thats the case, When i switch to a z8/short z6 needle jet, I am looking at rejetting both the mains and pilots now correct? Any idea of a short range of jets I should buy?
edit2: 4. For the pilot sizes, Your chart states that anything over 40 is the bs30/96 style, although my carb float bowl requires the vm22/210. Is the size going to differ much changing to the z8 needle jet than what i have currently?? I assume the factoring differences to determine the pilot size is floatbowl type, needle jet and needle.
Unless you tune the needle height for pilot to midrange transition instead of tuning pilot jet?
Currently at 142.5 mains and 30 pilots with 4n8's and z2
edit1; more research tells me the z8's are slightly richer than z6's.
Edit 3: the more I think about this. I doubt there's a tuning issue with the carbs besides maybe the pilot section currently. I'm going to try increasing the size of the petcocks intake and fuel nipple, as well as raising fuel level a tad and see if that sorts it. The bike runs great all the way to redline on the street everywhere besides constant highway speed at 110km/h. If lowering the needle increases the surging problem on the highway I will know it's leaning out and it's a fuel supply issue.