MOSH,
Difficult decision. Also depends on if you moto all the time or bush ride. I was in the same spot a couple of years ago, sitting in a coffee shop across from the honda dealer with $10K in my pocket. Buy or fix up my '92 500! I sat for an hour but couldn't come up with enough things that a new 4-stroke would do that much better than my '92 500, worth the $10K. Bought a speed boat instead. Here are some things to think about:
1. 500 has more power. Extra power for a 450 comes in $1000 increments. Nothing I like better than passing a new 450 with a $1000 titanium pipe on my '92. Definitely a holeshot machine.
2. In real weight on a scale, 500 is probably 15-20 lbs lighter.
3. 500 gets more hours out of a top end than a 450 and is cheaper to rebuild(lots cheaper).
4. 500 takes lots less maintenance.
5. 500 is quieter.
6. 500 Starts better.
450 has:
1. better suspension but that can be fixed with a revalve.
2. Looks cooler but some new plastic and graphocs can mostly fix that up.
3. Turns better. That can be mostly fixed up with chassis setup and proper tires.
4. Likely to be faster on an MX track.
5. Simply newer looking.
It's a tough decision. All I know is, when I ride in a big group of mixed bikes, my 500 is the one at the top waiting for the others. Hope this helps a bit. Cam.
