Yah. The sidestand safety switch would be my first guess.
As I'm mentioned before, certain frequencies can excite the sidestand causing it to move up and down a little bit.
When it moves down, it can trigger the kill switch that's built into it by the hinge and if it does, the engine will die. With the switch turning off and on rapidly it will seem like the engine is hesitating or lugging.
Devante, unplug the switch wire where it plugs into the main harness and see if it doesn't fix the problem.
I'll give it a try.
I know it's kind of hard to understand but basically in 1st gear at 35~ MPH, my RPMs are way too high. Around 5,000 and the bike sounds like it's about to fall apart.
In 2nd gear, at around 35 MPH, the bike will kind of 'burp' every few seconds. The RPMs are around 3,500.
If I push it to 40 MPH (4,000 RPM), things get to normal.
So I'm just having trouble going around 35 MPH.