I know i may have to go up in jet size for the pods, but not to the extremes that i have at the moment.
What have you got at the monent? My 750 on pods and 4-1 is on 137.5, a big jump from 110 standard. It seems the 750 need more upjetting, compared to the 550 and 1100's..
Was that plug chop form WOT? (wide open throttle) you need to rag a 750 with quite a long bit of road to do it, lower 'normal' speeds your pilot airscrew and needle position makes much more of a difference, Unless you did a 100 mph plus plug chop you might not be reading the main jet mixture. Try leaning out the pilot airscrew and needle position and see if it makes any difference. If not you are probably too big on your mainjet.
And strobe check your timing and advance.
1980 Gpz550 D1, 1981 GPz550 D1. 1982 GPz750R1. 1983 z1000R R2. all four aces