Magazine advert promoting the features of Yamaha MX series, especially MX175

Yamaha MX Motorcycles

The Yamaha MX series is an iconic run of dirt bikes introduced back in 1973. The series pre-dated the legendary YZ series, which saw incredible success in competitive motocross riding. As the YZ series grew in popularity, the MX motorcycles became cheaper alternatives for everyone to enjoy.

Below, you'll find everything you need to know about this series of Yamaha motorcycles.

A Brief History Of Yamaha's Motorcross Pedigree

Yamaha is a brand that has always been one of the leading names in motocross innovation. Whether we're talking about shock suspension development or four-stroke engine integration, Yamaha has always been part of the conversation. In fact, many of the popular motocross bikes we see today owe a lot to iconic Yamaha designs of the past.

Yamaha made their first dirt motorbike in 1968. The DT-1 was an overnight success and grew to huge popularity over the following years. By 1975 Yamaha was making big innovations, most famously with the introduction of "MonoShock" rear suspension on their dirt bikes.

The manufacturer continued to be a major player throughout the 80s and 90s, and saw particular success when four-stroke motorcycles were allowed to compete against two-strokes in 1996. The Yahama YZ400F became the first four-stroke bike to win an AMA Supercross event.

The Iconic MX Series

MX Models

The MX series was made up of a number of motorcycle models. Each one was designed to offer a smooth off-road experience, but differed in engine size and additional features. The result is a range of motorcycles that are appropriate for a total novice up to a professional rider. Here are a few of the most iconic models of the series:

Yamaha MX100

The MX100 was the smallest capacity machine of the series, but it wasn't the first to be released by Yamaha Motorcross. It was introduced as an entry point into the dirt world, providing new riders endless fun without going overboard on power.

The two-stroke engine could provide a top speed of 55mph, which is more than respectable for a 100cc capacity. With narrow yet chunky off-road tyres, riders could expect good grip on all surfaces and plenty of quick agility to develop their skills.

Yamaha MX250

The Yamaha MX250 was released in 1973, following Yamaha's great successes in the 1972 Motocross Grand Prix. This bike was the ride of the legendary Hakan Anderson, who raced the MX250 to become the 250cc motocross world champion.

Yamaha MX360

The MX360 was one of the earliest iterations in the series, and was Yamaha's top of the line motocross ride prior to the introduction of the YZ series.

This bike brought a ton of new innovations, including Autolube oil injection, Thermal Flow rear shocks and Torque induction. The MX360 remains a firm favourite amongst motocross fanatics.

Yamaha MX400

The MX400 was the largest capacity machine of the series. The big engine certainly performed impressively and the bike could touch 85mph when it was cranked to the max. The MX400 also has an iconic white and yellow design that has enthusiasts weak at the knees to this day.

Key Features Of MX Bikes

Two-stroke engine

The MX series made use of single-cylinder, two-stroke engines in their design. As a result, the bikes were fast, fun, smoky, and loud. To this day there's nothing quite like a stroker, and an MX bike is one of the best examples of this engine in a motocross setting.

Off-road tyres

Chunky off-road tyres were staples of the MX series. This rubber provided a smooth ride across various types of terrain, and could be relied on to grip into slippery surfaces. The thick tyres also minimised the chance of punctures, which could bring a great motocross session to an early end.


Yamaha's MX engines used a classic air-cooling design. Although air-cooling is generally considered to be inferior to liquid-cooling today, in the 1970s it was the norm. Air cooling does have its own benefits though, such as better fuel efficiency and lower overall weight.

Low centre of gravity

One of the key design choices with this series of bikes was a low centre of gravity. Having a low centre of gravity is essential for riders to be able to accurately manipulate their bikes and stay in control. As a result, the Yamaha MX experience is quick, agile, and electrifying.


One of Yamaha's biggest contributions to the motocross world was the invention of their "MonoShock" rear suspension system. This design used a single, larger shock absorber to give the bike more suspension travel at the back. This made riding and landing jumps much less jarring for the rider.

Autolube oil injection

The MX series also featured Autolube oil injection, which was another revolutionary system developed by Yamaha. Autolube meant that riders didn't have to mix oil and fuel themselves, instead the oil would be automatically injected at the optimal ratio.

This removes the guesswork from the process and greatly improves two-stroke performance.


Can you still buy MX series parts and accessories?

MX series parts are not widely available these days and it can sometimes be hard to hunt down the equipment you need. Second-hand marketplaces such as eBay are probably your best bet, with parts emerging there fairly regularly.

Some MX parts, such as fork seals, are still manufactured by aftermarket brands. In addition, since the MX series shares many design elements with the YZ series, there are a few parts that are compatible with both.

Does Yamaha have a good motocross and enduro bikes history?

Yamaha's motocross history is one of the most impressive in the industry. The brand is known for making some incredibly important innovations in the dirt bike world, such as the introduction of the amazing MonoShock system.

Yamaha has always been an important competitor across the different motocross categories and it doesn't look like they're going anywhere any time soon.

Is it expensive to buy an MX bike today?

Although Yamaha MXs are getting rarer and rarer, the motorbikes can still be had for fair prices on the second-hand UK market. They don't come to market too often, so make sure to stay on the lookout.