I see specs listed for KL300R from early 2000's as having 33HP. Is that BS? Those were carbed, kicker only. But otherwise, externally, the motor looked the same. You can't get that kind of power out of the current bikes with all of the mods.

 

Could it be that they used to measure horsepower at the output shaft instead of the rear wheel?

 

Probably partially BS, but on the other hand, they didn't have to meet EPA/DOT regulations as off roaders. The first street legal KLX250 was in 2006 in the U.S. Not sure about other countries. The 1994 KLX250 was the fore runner for the KLX300 which came a few years later. Again, no pollution restrictions. But even back with the 300s the hop up to gain power was to install a flat slide pumper carb - TM36-68 - and a less restrictive exhaust. There was a cam difference in the earlier bikes too, I'm not sure which one though. You'd have to look through the parts numbers to see what year was different.