Why doesnt 2X the HP mean 2X the speed? Physics/Engineering

[woodsy]

OK, here is the deal:
My 2000 KX500 against a 2002 CR250 (new) in a roll on drag race, on the pavement from 2nd gear.  Riders within 5 pounds of each other. The KX has a slow but steady pull away from the CR but not like one would think.  Trade riders and the results are identical!
After riding my friends CR though I noticed and he noticed as well that the KX had a major "thrust" feel to it that the CR didnt even come close to.  I am assuming that this "thrust" is "torque" and that even though the torque is massive it doesnt translate into drag racing type "quickness" - WHY???
EVERYONE - Please feel free to give your thoughts, you will get NO negative feedback from me gor ANY thoughts.  It would GREAT if some real "physics" major would grab this and run with it!
Thanks!
Woodsy

[Paul]

Do you need a top end in that 500?

I ask because my nephew (130Lbs) on his 2003 CR250 will get ABSOLUTELY destroyed by me (231Lbs.) and my 500 in a drag race. What gearing does the 500 have?

One thing to keep in mind is that the '03 CR250 is reported to make almost 52HP thats REAL close to the power output of a 500 (60HP) - Don't feed me that stuff about 64HP. I dyno'd mine after a pipe and reed cage and it was 66HP but loads more powerful than stock. The 250 has HP but gives up torque do it's small-ish CID. There is also close to 20Lbs difference between my then stock (238Lbs.) KX500. Don't believe everything a manufacturer prints The CR250 weighs in at 218Lbs.

SO... if we take weight, power, torque into consideration that 250 still shouldn't be running too close to a fresh 500, but it may run closer than you expect.