The 04/05 models have an external oil cooler, the 06+ do not. (I have never had issues with running hot) The 06+ is a tad bit faster do to the higher compression. 06+ have a better carb. 06+ has longer wheel base, better handling at speed. 04/05 better at tight turns. HRC kit for the 06+ is a better bang for the buck investment.
Check the frame for any cracks. Run it through the gears, check the air filter, lift wheels off the ground and check for any free play in the bearings. NO OIL LEAKS
Thank you to my 2012 Sponsors:
Dynamic Graphics, Inc.