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MOTOCROSS ACTION’S MID-WEEK REPORT  PHOTO OF THE WEEK: PART 1 Yesterday the MXA wrecking crew rode the 2011 Yamaha for the first time. Yamaha held their introduction at the awesomely prepared Racetown 395 motocross track near Adelanto, California. The 2011 YZ450F received a very small number of updates, but it wasn’t any less fun to […]


2004 YAMAHA YZ125 What’s new on the 04 YZ125? 1. The shape of the scavenging port and exhaust port is changed (the timing is also revised) 2. The setting on the YPVS governor spring is changed for better acceleration in the low to mid. 3. The carb setting at the bypass port is changed. 4. The exhaust pipe is increased in overall length by 5mm, mostly at the head pipe (not on European models). 6. The diameter of the stinger is increased 1.6mm (in front of the silencer) 7. The shift pedal is downsized 9mm…

2002 HONDA CR250

(click on photo) CR250: 1. New third generation twin spar aluminum frame and swingarm. (1.1 lb lighter than last years frame) 2. Redesigned rear brake system with integrated reservoir and master cylinder. 3. All-new case-reed engine. 4. RC-style exhaust valves (similar to the CR125) with as electronic control module that uses engine rpm to calculate exhaust position and signal a DC servo motor to adjust the RC valve. 5. Magnesium clutch cover. 6. Showa suspension front and rear. 7. Aluminum spoke nipples…


We can’t tell you how to jet your bike. It’s a big world out there (and we don’t know you all that well). However, we can tell you what jetting we run in the MXA test fleet. Take into account that we race in a Mediterranean climate, near sea level, within sight of palm trees and never far from a Double Latte. We also run fresh 92-octane gas, work on our bikes every week, clean the filters, change pistons and rings regularly, are alert to pinging and haven’t changed oil brands in over a decade. This is t…