A couple of years ago, I bought an 01 Rev3 270 with almost zero wear on the original tires. Power was very sharp right off the bottom with the initial crack of the throttle. It was much much sharper than my 2014 Evo 300 2t Factory off the bottom. (The 300 Factory sort of took off mid range.) I added a full millimeter of base gasket for a total of 1.5 mm. Then I installed the heaviest flywheel weight I could find. It was something from a Techno marked Ducati. Power delivery is much smoother and it is easier to kick. I would think anyone who likes vintage bikes like a TY250 would like flywheel weights on modern bikes.
I also find that going down a tooth on the front sprocket helps. The clutch out speed is slower so it makes clutch use easier in slow tight turns. (I'm no clutch master.) But, based on your injury description, you may have been going pretty fast. A smaller front sprocket also reduces the tendency to build speed with a series of obstacles to clear like log-log-log. If the throttle does get away from you, the bike will also run out of RPMs quicker with a smaller front sprocket so you can't get in as much trouble. I have tried 2 teeth lower but find it reduces the ability to get up and over things in first gear. A smaller front sprocket does reduce top speed if that is important.