INSIDE THE WORKS YAMAHA YZ250FM & YZ450FM GP BIKES
For the last couple years, part of Yamaha’s Monster Energy deal had them racing the World Motocross Championships in black livery. Not only was it ugly, but it didn’t do much for Yamaha to disquise their bikes to look like energy-drink cans. Now for 2014, the Yamaha Grand Prix team is back in blue. The riders are Christophe Charlier (250) and Jeremy Van Horebeek (450).Christophe Charlier’s works YZ250FM features a YRRD (Rinaldi) engine with a one-off transmission, Vertex piston, hydraulic clutch, Akrapovic exhaust, Xtrig clamps, GET ignition and DT-1 air filter.Jeremy Van Horebeek’s YZ450FM is equipped with revised cams, valves, gear ratios and special Kayaba air forks.
Jeremy Van Horebeek (89) has moved to the top spot in the Yamaha Grand Prix food chain. This YZ450F is considered the fifth generation of the fuel-injected versions and dates back to the 1997 prototype YZ400 that Doug Henry raced.
The works Kayaba shock features a unique array of clicker adjustments—in red, white and blue.
As with all high-end factory race bikes, the works Yamahas get titanium footpegs—mainly for the rider’s pysche.
Although Christophe Charlier is Yamaha’s official factory rider, much of his YRRD YZ250FM will be shared with support riders Luke Styke and Petr Petrov. Dixon Yamaha’s Max Anstie will race a Cosworth-prepared engine in the 250 GP’s.
Insiders claim that the YZ250FM uses a dual-injector system along with a GET GPA traction control ECU. The ignition cover is magnesium, and the special cylinder and head are cast at Rinaldi Racing in Italy. Jeremy Van Horebeek’s YZ450FM engine uses more stock parts than Charlier’s YZ250FM, but it still gets the Rinaldi touch when it comes to the piston, cams and crankshaft. It also can be equipped with an electric starter.
The exhaust systems on both the YZ250FM and YZ450FM are from Akrapovic and are tuned to meet the FIM’s 112 dB limit.
Both FM’s use CRM carbon fiber fuel tanks that come in slightly larger sizes for gas-guzzling sand tracks.
Brake rotor size varies from 270mm to 280mm depending on the track. The rear Braking rotor is 245mm.
The brass cap covers the air valve on the next-generation Kayaba PSF air fork. .