I have an 02 WR250F that I have dual sported for riding to and from different trail systems in northern Michigan. For the off road (tight and snowmobile trails) ) I prefer the gearing and drive train of my stock YZ250F. I could convert my YZF into a dual sport but the bike would only do about 65mph wound to the limiter. Ultimately I would like a YZF with an overdrive for riding the road to and from trail systems. I would like to change the first three or four gears of my WR to YZF gearing. Along with changing the gearing I would also change the drive train to stock 12/48 with a 19 in. rear rim. I want a dual sport bike that would be trail friendly but also do a top speed of 75- 80 so I won't be winding it out on the highway at 60-65 mp Has anyone ever changed/swapped gears in the tranny? Can I swap out 4 of the 5 WR gears with YZF gears? With the changing of my WR drivetrain (12/54) to the higher drive train ratio of YZF12/48 (best I can recall for drivetrain ratios), should I use a WR 4th gear as my final drive or a WR 5th gear. For the final drive, the WR 4th gear might not achieve the needed road speed (75-80mph) and the WR 5th gear might be too high (60 mph is achieved with just a crack of the throttle with the 12/54 - 18 drive train. What should I do. Are there any other gearing recommendations to achieve YZF type gearing with an overdrive? I do have the mechanical skills to disassemble and reassemble the entire engine and tranny. If this at all possible, i need some engineering help or advice from someone who has done this to get it right the first time.