Your tire size, if different from factory, will affect the speedo accuracy too.

 

Check your odometer against the mile markers by the side of the road. If the odometer is off, so is the speedo.

I have 43 in the rear, but down one in front, and my speedo and odometer are almost 10% high.

 

I was riding with my dad the other day, we were getting passed, I didnt know why. I thought we were going like 65 in a 55, well we were doing 55 in a 55. Plus, I KNOW the rear sprocket says 45.

 

Well, it's probably stock gearing. There is almost... take that back... there is NO advantage going down 1 tooth in the front on an F3 (so minimal you'd never know it).

I would pretty much bet that you're all stock. Tire size/pressure/sprocket size are all going to effect your true speed when compared to it's displayed reading. As far as what speed at what RPM you have more variables. Every bike is different and depending on how well it's been kept, how hard it's been ran, what overall condition the engine is in...

You guestimated RPM/speed ratios sound quite normal.

Keep in mind a brand new bike off the floor will be off by 5-10%. Nothing new and definitely not a big deal...

 

Well turns out it is -1 +2 and the speedo was 20% off. I installed the speedohealer today and checked the speed with a gps. At 107 indicated, the GPS said I was doing 104. Hell, thats close enough for me. I'll calibrate it perfect when I buy some new tires. Thanks for the help.