Yamaha YZ450F Motorcycle

Ringleader: **Brian Catterson
**MSRP (2010): $8090
Hours: Approx. 25
**Accessories & Modifications: **Dubach Racing Development exhaust, radiator lowering kit and hour meter

Man oh man, motocross can be frustrating!

Roadracing is much more straightforward. The track never changes, a good lap time is a good lap time, and you can reasonably expect to finish about where you finished last time.

In motocross, the start is critical, the track changes from lap to lap, and you get tired as hell near the end of a long moto. And so I've finished as high as fourth and as low as 14th-on the same day!

Last time I told you I'd used Yamaha's GYTR Power Tuner to take the edge off the YZ450F's low-end hit. Since then, a conversation with Doug Dubach convinced me to try one of his company's exhausts, and I've gone back to the stock fuel injection and ignition settings. Like I told Doug, the last thing I needed was more power, but as he explained, his pipes are designed to smooth power delivery. According to the former AMA Supercross winner, there's a flat spot just off the bottom that makes low-end throttle response feel abrupt; it hits and then falls flat for a split-second before picking back up. His pipe fills in that hole. I went with the basic stainless-steel/aluminum version ($649.99 from www.dubachracing.com), which can be fitted with a spark arrestor screen and quiet-core insert for off-road use.

Dirtbike exhausts are easy to install, but because I was bringing my Sprinter van in for warranty work at a dealer right down the street from Dubach's shop, I left the bike with him. While he had it, he installed one of his radiator-lowering kits ($49.99). This uses a host of red-anodized aluminum brackets to drop the two radiators by about 1 inch. That doesn't sound like much, but remember it's not just the weight of the radiators but also the coolant inside.

Dubach also threw on one of his hour meters ($57.99 with mounting bracket). Why install an hour meter when the Power Tuner keeps track of run time? Well, besides the fact that not everybody wants to spend $280 on a Power Tuner, the hour meter only has to be plugged in once. Moreover, its location just forward of the fuel tank lets you keep track of how long you've been riding, which is handy for timed motos or for gauging your fitness.

Back at the weekly REM races at Glen Helen, the revised YZ450F worked even better than before, slotting into ruts, banking over in berms and letting me grab bigger handfuls of throttle to start my drives earlier. Not only that, it's even more stable now-and it was already super-stable.

Two big thumbs up!