I have a Y2K 400EX. I put my Garmin 12 GPS on the handle bars. 67.4 STOCK. ENOUGH SAID ABOUT SPEED............

 

ok like i said it is different for everyone. different people weigh different. i only weigh 120lbs and i was clocked with my dads radar gun
(hes a police officer) at 74 mph and if you don't beleive me you can come see for yourself

 

Elevation could also make a huge difference, as most bikes produce quite a bit more power closer to sea level (air is denser). Also, one bike might roll off the assembly line with 27HP, while the next has 29, there are always fluctuations in production.

 

I WAS CLOCKED AT 78MPH BUY A CAR BUT DIDNT BELEIVE THE GUY THAT CLOCKED ME. I LIVE AT SEA LEVEL AND MAYBE HE WASNT TO FAR OFF THEN IT DEFINATELY DOESNT GO ANY FASTER THAN THAT AND MAYBE WILL GET 70MPH THEN ALL I KNOW IS WHEN THE THROTTLE IS FULL ON PAVED SURFACE TOP SPEED IT SEEMS YOU CAN FEEL THE FRONT END WANTING TO LIFT. IF I WERE GOING TO MAKE IT ANY FASTER I THINK THE FRONT FENDERS WOULD NEED TO BE TRIMMED. TO HARD TO CLOCK A BIKE WITH A VEHICLE BUT RADAR SHOULD BE GOOD.