2012 Yamaha YZ250F

Ollie Sharp

iKapture

Yamaha’s updated 2012 YZ250F is a culmination of YZ-F strengths over the last two generations. Simply calling it a BNG upgrade makes Yamaha’s big wigs grimace like they’ve just sucked on a lemon. Amongst the modifications the engine received updated internal components, there’s a new highly tuned carburetor, the frame and swingarm were redesigned for additional rigidity and the suspension has taken cues from the YZ450F – all of this barely two generations after the 2010 YZ250F received its major overhaul.

New suspension components have been bolted on and the triple clamp offset has been reduced. In essence Yamaha has produced the 2012 YZ250F to turn tighter, produce more power and rev harder all the while increasing its on track stability.

On paper the 2012 YZ250F sounds very promising, but the lack of EFi may still prove to be a deterrent for many quarter-litre motocross junkies. Although, according to Yamaha it isn’t far away.

Still Full Carb

Despite the 2012 YZ250F not featuring fuel-injection, Yamaha still believes EFi isn’t the be-all-and-end-all. And engine tuners will agree that there’s nothing to despise about a well-tuned carburettor. However, Yamaha’s YZ250F is the only competitive bike in the class to use a five-valve head design, with everyone else using a four valve head arrangement. And it got us wondering, is that the root of the problem or is it simply a general performance issue? We directed that query straight to Yamaha’s communications manager, Sean Goldhawk, and the answer couldn’t be any clearer.

“During testing, our engineers fitted EFi to the bike and couldn’t get anymore horsepower out of the engine compared to the carby. While there are some emissions control and end-user benefits with EFi, those alone weren’t enough to offset the weight penalties that fuel-injection carries over a carburettor. At 103kg (2012 YZ250F claimed weight) it’s by far the lightest four-stroke 250cc motocrosser on the market. Also, EFi still has it problems, especially when it comes to debris getting into the injector. However, we do believe fuel-injection is the future; but until it becomes super-lightweight, the carburettor is still the way to go.”

On the Front Foot

It’s well known that Yamaha Japan is busy testing and perfecting fuel injection for a possible 2013 YZ250F release date. However, the technology actually already exists in MXGP. By who, you may ask? Italian Yamaha tuning specialist, Rinaldi, has been toying with Monster Energy Yamaha’s YZ250F, raced by Gautier Paulin in the MX2 class. Initially, the bike seemed to lack horsepower, but has since won a moto at the Germany GP. The thing must be fast…

Specifications

October Issue

Don’t forget to catch the full 2012 YZ250F ride impression inside Transmoto’s October Issue 13 on sale September 21.