Find My Brake – Yamaha YZ250/YZ250F
June 1, 2022 Tips & how-to guidesWe look at the Yamaha YZ250/YZ250F model range from 1989 to the present, and what braking system parts Bendix supplies for these motorcycles.
Dating back to 1974, the history of the Yamaha YZ250 has been synonymous with the progress of Moto-X for almost five decades. No other machine has hatched so many revolutionary innovations. The seemingly endless list of firsts includes reed valves, single-shock suspension, and power valves.
On top of all the firsts, there’s a very significant last on the YZ’s resume. Today it stands as the last 250cc two-stroke from Japan. That makes it the longest-running production dirt bike in the world - maybe even the longest-running motorcycle model of any kind outside of Milwaukee and Russia.
And in Australia, the Yamaha YZ250 has proven fundamental in carving out Yamaha’s off-road racing legacy. Having equipped teams such as Craig Dack Racing - that single-handedly secured 50 national championships in motocross, supercross, and off-road racing over 25 years – Yamaha has established itself as a force to be reckoned with in off-road motorcycle racing Down Under.
Notwithstanding the two-stroke YZ250’s success, to counter exhaust emission concerns Yamaha developed a four-stroke alternative to the wildly successful YZ250 in the form of the YZ250F. First released in Australia as a 2001 model the YZ250F again revolutionized off-road racing with Yamaha's patented ‘five titanium-valve’ design and innovative four-stroke technology. This combination gave the YZ250F the broad-power band of a four-stroke engine with the lightweight design enabling handling found in smaller 125 cc two-stroke motorcycles – making it an immediate hit on Australian dirt tracks.
Yamaha YZ250 1989 to Present
Following the conversion to liquid-cooling in 1982 and the introduction of reed-valves and YPVS exhaust valves for a wider spread of power, the Yamaha YZ250 engine underwent a series of minor updates – including changes to the bore and stroke, and power-valve - until 1999 when Yamaha introduced a brand new engine.
The engine featured a Keihin PWM38 Powerjet carburetor with ignition to suit, a new long-stroke configuration - 66.4 x 72mm from 68 x 68.8mm – and a new cylinder head to match the smaller bore. At the same time, Yamaha gave the YZ250 a new YPVS exhaust power valve, a more vertical cylinder with revised porting, changed the piston and piston pin, lowered the crank, and revised the crankpin. The new YZ also gained an upgraded gearbox and shift mechanism, and a revised exhaust pipe and muffler.
To match the engine upgrade Yamaha went to work on the frame and Kayaba suspension with many internal changes to the upside-down front fork, such as valving, pistons, and oil seals. The gas-filled rear suspension got a longer-stroke shock absorber with new valving and a larger gas canister. And to reduce unsprung weight, a new swingarm, sprocket, hub, and axle were fitted. All of the updates were aimed at continuing the YZ250’s competitiveness on dirt tracks around the world.
In 2005, in keeping with the latest chassis technology the Yamaha YZ250 got an aluminum frame. Yamaha used a conventional backbone layout instead of the perimeter design favoured by many other manufacturers, even though Yamaha switched to a perimeter layout for the YZ250F four-stroke.
With an unquantified demand for YZ250s in more utilitarian roles, Yamaha came out with a ‘de-tuned’ off-road version of the bike in 2016. The YZ250X got a kickstand, a wide ratio gearbox, a remapped ignition, and a more compact pipe. The suspension was also revalved for off-road use. However, the YZ motocross version remained the jewel in the lineup.
While other manufacturers have thrown in the towel on the two-stroke world a long time ago, Yamaha has kept its hat in the ring with the potent YZ250 for more than 47 years. And while it hasn’t received any major updates since the introduction of the aluminum chassis, it has remained competitive in both motocross and off-road competition.
Yamaha YZ250F 2001 to Present
The Yamaha YZ250F was the first modern-day 4-stroke 250cc Moto-X bike on the market and the first to win an international race. In Australia, the YZ250F has been by far the bike of choice, having racked up championship after championship and shootout win after shootout win. This groundbreaking race weapon has racked up Moto-X National championships in both MX2 and MXD, Australian Supercross Championships, and Australian Junior Nationals.
First released in 2001 the little Yamaha had a five-valve, DOHC, four-stroke engine, bolted into a steel frame with an aluminum subframe. From day one the quarter-litre four-stroke was competitive, although it initially competed in the 125 class against the two-strokes. For this reason, Yamaha adopted an evolutionary approach to updates, with the first real face-lift taking place in 2003 when the YZ250F gained an automatic decompression governor system, a redesigned crankshaft along with a new oil-circulation system.
Systematic improvements such as the all-aluminum perimeter frame introduced in 2006 and an increase in compression ratio from 12.5:1 to 13.5:1 in 2008 were enough to keep the YZ250F on top of its game until 2014 when Yamaha decided it was time to lift the bar.
For 2014 Yamaha applied the many lessons learned on the YZ450F to the smaller YZ250F, complete with a rearward-leaning cylinder that featured the intake in front and exhaust in the back. What's more, the new YZ250F was also equipped with Keihin fuel injection with a 44mm throttle body and a 10-hole injector fed by a battery-less electric fuel pump. The 3D-mapped system collected its data from multiple sensors, reading throttle position, intake pressure, intake air temperature, crankshaft rpm, and even the coolant temperature to signal the ECU to adjust the fuel mixture. Although the new YZ250F used the same 77.0 x 53.6mm bore and stroke dimensions as before, its new twincam head was fitted with four titanium valves in place of five.
Chassis upgrades to the 2014 Yamaha YZ250F included an all-new bilateral-beam frame, while KYB’s air-oil separated, speed-sensitive fork, and shock of the same make were also updated.
In 2019, Yamaha unleashed a heavily updated YZ250F with improved handling and even more power – and electric start. Its liquid-cooled DOHC 4-stroke engine received a new cylinder head with a modified intake-port shape and a revised camshaft profile. By redesigning everything from the intake system and clutch, to the 5-speed transmission, ECU, and water pump impeller Yamaha engineers wanted to make sure the YZ250F outshone the outgoing model by a wide stretch. And this it did, with the new YZ250F claiming another Australian Supercross Championship and Australian Junior Motocross Championship within months of its release.
For 2021 the YZ250 had very few changes to the valve train aside from a redesigned exhaust cam. Most of the emphasis was placed on improving airflow into the motor. The intake port was reshaped, the Mikuni throttle body grew in size, the air boot was reshaped and the airbox lid was vented. On the other side of the motor, the exhaust system was redesigned with a longer canister. The ECU was remapped, and the cam chain, cam-chain tensioner, gearbox, clutch basket, and water pump upgraded to improve reliability.
Although the YZ250F has only received minor updates over the past three years it has remained at the forefront of competition even claiming victory in Dirt Rider’s Motocross Shootouts in 2014, 2015, 2016, 2017, and 2021. With 2022’s well-deserved victory, making six titles in this prestigious comparison test since the bike’s radical redesign in 2014.
In the tough world of competition, every last fraction of a second counts, and anything that will give you an advantage is worth its weight in gold. So, when it comes to braking you will be pleased to know that Bendix offers a range of brake pads developed for off-road competition that will give you the edge.
Bendix Brake Pads For The Yamaha YZ250 And YZ250F
As Australia’s largest automotive friction material manufacturer, Bendix has been at the leading edge of braking technology for close to 70 years and has now taken that expertise to the world of motorcycles.
Bendix Moto currently offers two brake pad types – Ultimate+ and Street Road Track. Each pad type covers the needs of a specific range of motorcycles and how they’re used - from putting around on the daily commute to full-blown track use. Bendix Moto’s extensive catalogue also covers an enormous range of different motorcycle types including off-road performance ‘bikes such as the Yamaha YZ250 and YZ250F.
Bendix Moto Street Road Track Brake Pads offer the kind of braking performance required for high-performance applications such as those encountered in off-road competition. Designed to adjust to your riding style, Bendix Moto Street Road Track Brake Pads deliver consistent braking performance, with low fade, low wear, and high friction over a wide range of conditions even in the wet. This is particularly important in racing where frequent hard braking under unpredictable conditions really tests the performance of the brake pads.
Whether you are competing in Motocross, Supercross, or just enjoying a fast trail-ride with friends, Bendix Moto Street Road Track Brake Pads are perfectly suited to the high braking demands of high-performance riding.
Never get caught out by brakes that aren’t quite up to the job. Fitting a set of Bendix Moto Street Road Track Brake Pads to your Yamaha YZ250 or YZ250F means you can confidently go for a fast lap - anywhere, anytime, in all conditions.