I just put a twist throttle on my 03 shee and went to take a test drive and now it has now power in 1st. It does not rev right. In second its better and the rest of the gears are normal. I made sure to sync the carbs and wire together the thumb throttle wires. What could be wrong. Can this be jetting or plugs? Even if you keep it in first and open and close the throttle is just doesn't rev.

 

is the throttle cable tight enough

 

I checked the cables and the opening of the carbs and they seem fine.