bogs downs with quick twist of throttle

[rubbernecker]

I have a 1971 750-four that is all stock. If I slowly twist the trottle the bike does fine, but if I give it a fast twist in all gears it bogs down for a second and then takes off. I thought it was the carbs so I rebuilt them using the standard size factory jets. I believe its #120 for the main and #40 for the slow jet. I do have a huge whole in one of my pipes that I will be changing out tomorrow with a MAC canister exaust that is a 4 into 1. It also seams to be cutting out a little bit at higher RPM's Anyone ever have this trouble before?

 

[dan1951]

Try turning the air screws 1 turn out from closed and see if that makes a difference it does on My 72 then fine tune them. Did You sync. the carbs? Might have to go with a 125 main. or raise the main needles a notch.