How much faster are the new 450s than the 400ex? Will they smoke the ex ? Not so much in a drag race but on a mx track from corner to corner.

 

You mean the 450R? Riders being equal it will beat a stock ex from corner to corner on a bigger track. I found a 14t sprocket, pipe, moded airbox and proper jetting will give you a chance gears 1-3. Add a good top end cam/high compression piston and port and polishing and you'll compete. I got the holeshot against a piped YFZ last time out on the mx track, we were neck and neck til the first sweeping turn and I had the better line into it so I got him. This is a long straight too, I was in 4th going into the corner.

 

stock vs stock, the 450's are plenty faster. on a tight track, it could be a close race. on a more open area, get ready to get passed. drag racing, it isn't even a comparison. i have mine to the point where i can run pretty close to a stock yfz, but it took a ton. i haven't beat a piped and jetted one yet, so i still have more work to do.