I posted this in the RMZ450 forum and didn't get one reply (using my wife's userID) DR650 engine in an RMZ450 chassis? So here's the deal: I have an RMZ450 that I made into a trail bike. Although I love the bike, it tends to overheat when I ride it hard. I'm in Hawaii so it's pretty tough terrain up in the mountains and hot and wet down in the valleys. The prices of RMZ 450's have tanked so I'm thinking about "tardin'" it out instead of selling it. The engine won't last on the freeway commute so I was thinking about selling the 450 engine (it was built by Grant Matsushima, he builds engines for pro motard guys including Kevin Swantz) and stuffing a DR 650 engine in there. I can get a parts-only DR 650 for $100. Has anyone attempted this? I normally ride a DRZ400SM on the street but my wife started riding it and won't give it back. My other option is to trade my RMZ for another reliable Motard. What do you guys think?