Originally Posted by headtube
Difficult to define. A kind of bogging down but not so much that it stalls. I don't believe it's running on one cylinder momentarily until it reaches higher RPM's. It may be a carb issue. If I have (as disston says) two different Needle Jets than that may be it, because it only occurs at the lower end of throttle. I will order new ones of the same size, plus new Needles. My next move is to adjust the valves.
BTW... Main Jets are 165 - not 160 as they should be.
On a side note. I bought this bike "uncertified" for what I thought was a decent price. Why do previous owners always bugger things up by adding OR subtracting from a perfectly good motorcycle? Today I discovered that I have the wrong center stand installed.
Take appart carbs and measure everything and clean everything. Set valves and clean filter .... start from Veronica. Balancing the carbs by ear is the easiest thing to do. Engine off ... see that both open at the same time. It will be pretty close when you start it. It is not the voodoo you fear. Unless you are absolutely hearing impaired they will be ok.