Timing Dance ! Vacume Advance ?

The 800 is a little big. The secondaries do still have an air door. But it's counterweighted instead of preloaded with a spring. I would try a couple things.. First, for the primaries try leaning the power step of the rod, while going richer on the cruise step. You may need to play with rod and jet to get that. Second, try a larger squirtor, or try moving the link rod on the accerator pump arm to the hole closest to the pivot... It should be in the middle from the factory. Last, you can try to jet up a couple steps on the secondary. I run 750s on 360s normally and my feeling is you want to fool the engine into thinking the carb is smaller.