I weigh 190 and run a 5.1 spring on my 00 CR 250. My buddy weighs 180 and runs the same spring. The stock spring rate is 4.75 here in Japan, I'm not sure if its the same in the states. You can get a new spring for about $70 Its fairly easy to put on. My settings are as follows: Low speed compression 9 clicks out, high speed compression 2 clicks out, rebound 10 clicks out. Sag 97mm. Your settings will depend on track conditions. The track I ride at is usually hard pack. As for adjusting the spring, they make spanner wrenches specifically for adjusting springs. I just use a screw driver and rubber mallet. I hope this helps.:cool: