Re: My GZ 's top speed seems low
Even at your height and weight and laptop load, you should be able to reach 70 I would think (based on what I know from riding my GZ at my height of 5'10" and weight of 225). You're definitely taller and heavier, but you should still be able to go 65 still without too much struggle. Certainly much faster than 50 on an open throttle! It's going over 65 when other factors come into play (such as height, weight, wind resistance, road levelness, load, etc).
I don't know where the lack of power could be coming from, so I'll let the others chime in and try to help out there.
1982 Suzuki GS450 Bobber (SOLD)
2000 Suzuki GZ250 (SOLD)
1998 Kawasaki Vulcan 800A (Present Ride)