I'm sure someone will soon be able to help you. I'm more of a expert bike cleaner/polisher than a mechanic. My hands are like a babies bum still (47 year old medically retired / worn out bike cop in case your wondering).
If I were you I'd look first at fuel starvation
- a blocked fuel filter etc. Secondly the Carb
(blocked jet, mixture etc).
Once you have checked the fuel side of things the next thing to look at is air intake
(filter and housing) and then finally (and the biggest pain to sort out) - electrical
faults (including spark and HT lead / coil).
Sounds like it's probably something silly and minor (hopefully cheap to solve too). You really can't go much wrong with a Yamaha XT6E. These things are simply legendary...
You watch, the very next post will say I'm totally WRONG! lol.
is probably the best person to help you out?
Triumph Bonneville 800 (2004), Yamaha XT600E (1999), Honda XBR500 (1986).