2016 Yamaha YZ250X Off-Road Two-Stroke Review

Adam Booth | February 15, 2016

Two-stroke lovers rejoice! For 2016 Yamaha has taken its beloved and race-proven YZ250 two-stroke motocross bike and gently massaged it into an off-road bike. The all-new 2016 YZ250X has arrived and is ready for all forms of off-roading.

Turning the Yamaha YZ250 motocrosser into an off-road bike isn’t difficult. In fact, it’s been common practice in the off-road world for years now. Off-road trail riders and racers have simply been adding an 18-inch rear wheel, aftermarket exhaust, flywheel weight and skid plate, as well as tweak the already excellent KYB suspension. Modified YZ250s have been a great option for those who didn’t want to ride an orange off-road bike. Now Yamaha offers the 2016 YZ250X for $7390, a mere $100 more than the YZ250 it’s based off and, perhaps more importantly, $1309 less than a KTM 250 XC.

2016 Yamaha YZ250XAt a glance the 2016 YZ250X looks exactly like the YZ250 motocross bike, but there are key differences that make the YZ250X a potent off-road weapon.

Transformation X

The YZ250X sports quite few off-road focused changes when compared to the YZ250 motocross design. It might not look that much different externally but inside both the engine and suspension the YZ250X is all about off-road.

2016 Yamaha YZ250XYamaha just didn’t add some flywheel weight to the engine and call it good. In fact, Yamaha didn’t add any flywheel weight. Instead engineers worked on making the power delivery ultra smooth by reducing the compression ratio from 8.9:1 to 7.9:1 and increasing the head volume 2.1cc. The exhaust port height was also raised by 0.5mm, with the power valve shape updated to match the exhaust port. The rpm range in which the Yamaha Power Valve System (YPVS) now goes from fully closed to fully open is much broader, providing a more linear power delivery. The power valve now opens over a 1500 rpm range compared to 500 rpm on the motocross engine. New CDI timing in the mid-to-high rpms further smooth out the power delivery. The header pipe retains the same volume as the YZ250, but its shape has narrowed to help avoid trail damage. The muffler is the same as the motocross version. The YZ250X is a red sticker bike in California and sold as a closed-course dirt bike.

The YZ250X uses a five-speed transmission like the YZ250, but it is a wide-ratio design. First and second gears are the same as the YZ250 while Third is closer to second (same as adding one tooth to the rear sprocket). Fourth is like going down two teeth on the rear sprocket, while Fifth would be like going down five teeth on the rear sprocket.

The X’s KYB suspension is nearly identical to the YZ250, retaining even the same spring rates. What’s changed is the valving. While rebound is similar, the compression is much softer for a plusher ride. Other off-road essentials are the 18-inch rear wheel, kickstand, O-ring chain and a new fuel petcock with reserve. The new components bumped the YZ250X weight up two pounds (241 pounds with a full tank of gas) more than the YZ250.

2016 Yamaha YZ250X

The Sweet Smell of Two-Stroke in the Morning

Yamaha’s changes to the YZ250X engine are perfect. In fact, after months of riding motocross and a lot of off-road aboard the X, we prefer this engine set up to the standard YZ250 motocross version. The delivery is much smoother and makes awesome traction, all while offering up a little more power in the upper rpms. The YZ250X engine also revs an extra 500 rpm more than the YZ250, letting the rider carry each gear a little further before shifting.

Stock jetting is pretty darn good. We tested all the way to 5500 feet without issue, in weather between 50-75 degrees. We also used Yamalube at 40:1 with 91 octane pump gas. Depending on where you ride, some minor tweaking to the jetting will be necessary. We also used an FMF Gnarly pipe and muffler with a spark arrestor to avoid getting ticketed when riding on public lands. The FMF Gnarly pipe ($249.99) and Turbine Core 2 ($169.99) muffler worked really well, very closely mimicking the stock pipe and muffler. An added bonus of the Gnarly pipe is that it is made with 18-guage metal, making it stronger than stock. Yamaha did an excellent job when designing the narrower pipe on the YZ250X, matching it well with the engine changes to offer power that an aftermarket exhaust company will find hard to beat.

A wider powerband means the YZ250X can be shortshifted and lugged easily. It also revs incredibly long, making big hill climbs and long straights pure bliss. The stock gearing, matched with the five-speed wide ratio transmission worked well at all speeds. The engine’s impressive ability to chug down low, matched with a good spread between first, second and third gear helped the YZ250X conquer the most technical of trails. When you need a burst of power all it takes is a quick touch of the clutch and the responsive engine comes to life. Lifting the front wheel is easy.

2016 Yamaha YZ250X

Fun, exciting, manageable, and smooth are just a few ways to describe the YZ250X engine. The only drawback is that if you enjoy the high-revving engine too much you’ll discover the small gas tank only gets about 45 miles before running dry. We had to carry extra gas on many occasions, especially when surrounded by fuel injected four-strokes that get much better range. Our first modification will be a larger gas tank, then a skid plate.

Having an electric starter would be a cool feature on the YZ250X, but it would bump up the cost and the weight. As dirt bikers we lived without electric start for a very long time and are now spoiled by the bikes that have them. The YZ250X kick starts super easy, but we understand riders who refuse to own a bike without an electric start.

The YZ250 motocrosser is known for its lightweight feel combined with excellent KYB suspension, and thankfully the YZ250X retains all these accolades. The smooth but exciting engine helps the YZ250X feel nimble and light and it’s incredibly easy to change direction. Steep downhills, pivot turns and twisty trails are easier and way less tiring aboard the YZ250X when compared to a big 450 four-stroke trail bike. Of course, with lightweight two-strokes comes a bit of nervousness, especially over rock and root littered terrain.

MotoUSA has ridden many YZ250s over the years that were converted into off-road bikes, and a quality stabilizer works wonders for calming down a busy two-stroke and rider boosting confidence. The YZ250X is very responsive to sag changes, so if you need more stability adding a bit more sag will help. Running between 100-105mm worked best for 99% of the terrain we tested on.

The 2016 YZ250X isn’t a full blown off-road enduro trail bike, it’s a slightly tweaked YZ250 motocross bike. As such it works well in almost all off-road situations but still isn’t a slow technical terrain marvel. It is designed for GNCC type racing and shines as the speeds increase. The KYB suspension uses the same spring rates as the motocross bike so it isn’t a squishy ride and holds up well. The valving is much softer than the YZ250 and over super rocky terrain the 250X is a little unsettled and busy. Heavy riders felt the Yamaha was more planted in the rough stuff while lighter riders needed a bit more comfort in the beginning of the stroke. On the positive side, while it is acceptable in super rocky terrain, depending on your weight, the YZ250X thrives on every other sized bump, big and small, no matter the speed. The bottoming resistance is excellent, as is overall balance of the bike.

We also note that the KYB suspension works quite well for a wide range of riders and skill levels. We typically went in a few clicks on compression at the moto track and back to stock or softer depending on the type of off-road terrain. Our testers, ranging from 170 pounds all the way up to 220 pounds found the chassis and suspension impressive. The triple clamps also offer up handlebar mount options, making the cockpit adjustable for different sized riders.

What’s Missing

Huge props must be given to Yamaha, they are the only Japanese manufacture to offer up a two-stroke, let alone offer up off-road versions of their motocross bikes (YZ250X, YZ250FX and YZ450FX). Because the YZ250X is so heavily based off the motocross YZ250 and is only $100 more, there are a few things hardcore trail riders will want, like a bigger gas tank, electric start, skid plate, handguards and a stator capable of running lights. The lack of electric start might be a deal breaker for some, but thanks to the lower compression, the YZ250X kick starts incredibly easy. Adding a bigger gas tank, handguards and skid plate is a little bit of cash, but when you figure the YZ250X is $1309 less than a KTM 250 XC those potential deal breakers don’t seem as significant.

Braap

Two-strokes make sense for off-roaders. They are light, quiet, easy to work on and typically very reliable. Changing a top end out is easy and fairly cheap in comparison to a four-stroke. Yamaha deserves credit for making a push for off-road versions of motocross bikes and we will be comparing this to the KTM 250 XC very soon. All around, the YZ250X is a high quality machine with a strong reputation for reliability and performance. Dirt riders will appreciate the new Yamaha, as they now have another option in the off-road world.

Suspension Settings
Fork
Compression 13
Rebound 10

Shock
High Speed Compression 1-5/8
Compression 12
Rebound 11
Sag 100-105mm

 

Highs
• Excellent power delivery
• light and nimble
• Great suspension

Lows
• Small 2 gallon gas tank
• No electric start
• No skid plate

2016 YZ250X
Engine Type: Single cylinder two-stroke
Engine Displacement: 249cc
Bore Stroke: 66.4mm x 72.0mm
Cooling: Liquid-Cooled
Compression Ratio: 7.9:1 (YPVS open)
Fuel System: Keihin PWK38S carburetor
Ignition: Digital CDI Magneto
Starting System: Kickstart
Transmission: five-speed wide ratio
Final Drive: O-ring
Seat Height: 38.2 in
Wheelbase: 58.5 in.
Ground clearance: 14.2 in.
Front Suspension: KYB SSS; fully adjustable, 11.8 in travel
Rear Suspension: KYB shock; fully adjustable, 12.4 in travel
Front Brake: 250mm
Rear Brake: 245mm
Front Tire: 90/90-21” Dunlop AT81F
Rear Tire: 140/80-18” Dunlop AT81F
Fuel Capacity: 2.1 gallons
Weight (full tank of gas): 241 lbs
MSRP: $7,309

 

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Adam Booth

Off-road Editor | Articles | Enjoying single track in the mountains, hitting the motocross track or battling an EnduroCross track, if it's on two wheels Boothy will have a smile on his face. Adam has served a mega ton of years in the off-road industry as a photographer, writer and popper of wheelies.

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