Dirt bike racers that seek the best bang for the buck in terms of off-road motorcycle racing will be hard pressed to find a better style of racing than a grand prix. This genre is defined by a lengthy course that typically features both motocross and off-road terrain and obstacles which makes it more amusing to ride than a standard moto track. We headed out to Glen Helen Raceway to take part in an SRA Grand Prix race at the controls of Yamaha’s YZ125 and YZ250 two-stroke bikes. We’ll be splitting this review into two individual reviews by model.
2011 YAMAHA YZ250
Yamaha is the only Japanese manufacturer that still produces a 250cc premix burning motocross bike in the U.S. While it doesn’t feature the same cutting edge engine and chassis technology as its YZ-F four-stroke brethren it’s still a highly entertaining motorcycle to ride and race. In fact, if you’re not concerned about outright lap times or becoming the next James Stewart, you simply can’t beat a Yamaha two-stroke as it delivers a level of thrill and excitement that is impossible to imitate on a four-stroke.
In terms of sheer excitement you’ll be hard pressed to find another bike more fun to ride than a Yamaha YZ two-stroke.
One of the greatest advantages of two-strokes is their simplicity. Since the engine is lubricated via the fuel there’s no engine oil to check or change (the gearbox still uses oil which requires routine maintenance). Aside from making sure the air filter isn’t too dirty, checking the spokes, tire pressure as well as topping of the fuel tank with premix (30:1 ratio) bike prep time is a little faster.
Flip the fuel petcock, pull the choke lever and give it a light prod of the kickstart lever while simultaneously giving a small twist of the wrist and the engine fires to life with an ear pleasing shriek and a puff of blue smoke. While latest fuel-injection equipped four-strokes are getting easier and easier to start they still aren’t as easy as a good old-fashioned two-stroke.
On a fast and flowing track the YZ’s powerband works well. While it doesn’t have that instant snappy feeling bottom-end torque of a four-stroke, keep the throttle pinned and you’ll be greeted by a powerful surge of power that pulls, pulls and pulls, as long as you’re quick with the upshifts.
“You can’t go wrong with this bike,” says MotoUSA test rider Nick Thiel. “Sure it’s not going to win a drag race against a new 450, but it still has plenty of power to get up Glen Helen’s steep hills. There are few things better than the sound of the engine just singing on the pipe when you’re blasting around the track.”
Another plus is how much better the rear suspension performs with the shock tracking over bumps in a more controlled and less jarring fashion. Ultimately this makes the bike easier to control and reduces rider fatigue. While the bike performs best through wide-open parts of the track where you can carry momentum and really extort the power of the engine, it also works well in slow turns. With its minimal engine braking and the reduced reciprocating mass, it is a highly maneuverable machine. It doesn’t require a whole lot of effort to get turned and once laid over in a rut the back of the bike settles well and delivers a positive feel when you’re back on the power.
“For sure it requires a different kind of riding style, but when you put it all together it almost feels like magic when you’re riding,” surmises Thiel. “These things are so much fun. In my opinion it’s the best bike to just to play on and do some races once in a while. It’s cheap and easy to maintain too which allows for more time for riding.”