Yamaha Big Wheel 350 Specs and Review

Many fascinating ideas and accidental discoveries during the ’80s spawned technological innovations in the ATV industry. Among these was Yamaha’s concept of big wheels on two-wheelers. Although the outcome did not define a new motorbike category, it led to the birth of the Yamaha Big Wheel 350 – an all-season dirt bike that worked splendidly in the sand and snow.

The Yamaha Big Wheel 350 was an ambitious dirt bike produced from 1986 to 1987. A known rival of the Honda Fat Cat, this quirky motorcycle featured a five-speed transmission, a powerful engine, and a rear steel wheel that could fit with ATV-compatible tires.

Ironically, the Big Wheel’s seemingly inappropriate design three decades ago now makes perfect sense – so much so that its selling value has tremendously increased in the past few years. It is also one of those few bike models that could perform well in snow, ditching the need for a snowmobile in winter. These are only a few interesting points about the Yamaha Big Wheel. Continue reading to learn more.

Ahead of Its Time

The Yamaha Big Wheel (BW) is a cross-functional dirt bike produced from 1985 to 1989. It consisted of three different displacements, namely: the BW80, BW200, and BW350. The thinking behind the large wheelers was that their fat tires would boost rider confidence. Beginners could easily float along whatever type of terrain they traversed. Little did Yamaha engineers know that the Big Wheel was going to excel in an entirely different function.

BWs were not the fastest nor the cheapest, nor did they have razor-sharp handling. But they were the biggest dirt bikes around, reminiscent of an older, more modest version of the Batcycle. They had their niche, with only the Honda TR200 (a.k.a. Fat Cat) as their closest contender. More specifically, the Fat Cat was produced at the same time as the Yamaha Big Wheel 350. You can say that 1986-1987 was the Honda Fat Cat vs Yamaha Big Wheel era.

Yamaha Big Wheel 200

The first of the trilogy in 1985 was the Yamaha Big Wheel 200 (BW200). This dirt bike had a 196-cc four-stroke engine and was the inspiration behind the 1987 TW200. A year after, the Yamaha Big Wheel 80 (BW80) was released – a mini version of the BW200 designed for children. Both the BW200 and BW80 were manufactured until 1989 (for their 1990 models), leaving the BW350 with only a two-year production run.

Yamaha Big Wheel 80

Fondly remembered by novice riders in the late ’80s, the BW80 sported a 79-cc, reed induction two-stroke engine. It had a three-speed transmission with an automatic clutch, paired with fat tires that made it unbelievably easy to ride on any terrain. Not only was this beginner bike indestructible, but it was also high on the fun factor. Plus, the motor was easy to work on, and parts’ availability was never a problem.

Yamaha Big Wheel 350

On the other hand, an air-cooled, four-stroke single-cylinder engine powered the Yamaha Big Wheel 350, quite like the Warrior 350 ATV power mill. Although it did not make a ton of power, it was still more than what its counterparts could produce. The cast rims had massive 25 x 8-12 front tires and 23 x 11-9 rear tires, which added to the bike’s aesthetic and took away from its top-end speed.

Collectively, the Yamaha Big Wheel dirt bikes worked well in loose terrain and sand. The enormous rear tire allowed for plenty of grip provided you had aggressive treads. The more impassible the landscape was, the better the BW’s handling got. Shredding dunes and riding axle-burying bogs became a whole new playing field with these two-wheelers. Best of all, it became the ultimate snow bike without looking the part of a post-war half-track hybrid.

Yamaha Big Wheel 350 Specs (BW350T)

• Engine – The Yamaha Big Wheel 350 uses a four-stroke, air-cooled, single-cylinder SOHC engine. The power mill has a bore-stroke ratio of 83 × 64.5 millimeters (3.27 × 2.54 inches). It has an engine displacement of 348 cubic centimeters, a compression ratio of 8.8:1, and a wet sump lubrication system. A Y28P Teikei carburetor and a wet-type air filtration system handles the air-fuel mixture. Fuel tank capacity is 2.38 US gallons/9 liters, with 0.26 US gallons/1-liter reserve.
• Drivetrain – Uses a constant-mesh, five-speed wet multiple-disc type manual transmission. The primary reduction ratio is 70/24 (2.917). A dual-chain rear-drive is required to transfer power to the rear wheel.
• Ignition – The 350 uses a CDI-Magneto electronic ignition with a kick & mesh start system. It also has a flywheel magneto generator system and requires a 12V, 12 Ah battery with assembled dimensions of 6.31 x 3.19 x 5.12 inches (160 x 90 x 130 millimeters – L x W x H). Spark plugs are NGKD8EA (U.S.) and NGKDR8ES-L (outside of the U.S.).
• Tires – AT25 X 8-12 front tires and AT23 X 11-9 rear tires mount on tubeless cast rims – aluminum panel wheel for the front and steel panel wheel for the rear. Tire pressure recommendation is 5.8 psi/40 kPa (0.40 kgf/cm²). Avoid going over tire pressure limits of 4.4 psi/30kPa and 36 psi/250 kPa. Replace stock rubber with Carlisle All Trail II ATV Bias Tires (view on Amazon) and upgrade your wheels too if you prefer riding in more technical terrain.
• Brakes – Right-hand operated front drum brake and a right-foot operated rear drum brake provide the Yamaha Big Wheel 350 stopping power.
• Suspension – The dirt bike features a telescopic fork front and a dual-shock swing arm rear suspension with preload-adjustable shocks – allowing 6.3 inches of wheel travel for both. The front sprocket is 13T, and the rear sprocket is 37T. Shocks are a coil spring/oil damper at the front and a gas coil spring/oil damper at the back.
• Dimensions – Overall dimensions are 81.1 x 32.7 x 43.3 inches (2,060 x 830 x 1,100 millimeters – L x W x H). The minimum ground clearance is 9.45 inches, while the vehicle wheelbase is 55.1 inches. Curb weight is 141 Kg/310 lbs. Seat height is 32.1 inches.
• Exterior – The 350 has a steel tube diamond frame and plastic body material. The two-wheeler came standard with hand grips, front and rear fenders, a 45-watt headlight, and a 6-watt taillight.

Where Is the BW350 Now?

If the Yamaha Big Wheel 350 were such a good bike, then you may be wondering why it ceased production. The fact that inexperienced riders can drive the BWs with ease is what caused its downfall. The BW350 launched in the last two years before the 1988 Consent Decree. And even before the public knew about it, its sibling, the BW200, had already earned itself a bad reputation of snacking on ankles, feet, and lower legs of novice riders. Not to mention that its closest rival, the Honda Fat Cat, had a frame design that spun off from ATCs or all-terrain cycles, which were deemed unsafe and already racking up lawsuits left and right.

As with other manufacturers, Yamaha took a step back to assess what could potentially put riders in peril. Although the Yamaha Big Wheel 350 was not among these flawed vehicles and did not share the Tri-Moto layout, some features posed disadvantages. Hence, Yamaha decided to stop producing all three model lines in 1990 and concentrated on making ATVs more stable and less hazardous.

Reasons for the BW350 Discontinuation

Here are some of the cons that Yamaha took into consideration when it decided to stop producing this dual-purpose big wheeler:

• The bigger-tires-more-stability theory worked to a certain extent. But on slippery or muddy surfaces, the BW350’s gigantic knobbies led to unfortunate circumstances like riders falling in a straight line.
• The front tire did not bite in as much compared to the traditional skinny motorcycle tire, making it non-conducive to aggressive cornering. It also tended to offer too much flotation, which can lead to crashing.
• The BW350’s rear wheel had an unpredictable habit of wandering around wildly as it powered forward, especially on slick mud. Its propensity for slipping, sharp turning, and angle approach contributed to rollovers.
• Jackshaft adjustment was odd, and there was no standardized way of adjusting the rear chains correctly.
• Although bikers can jump the Yamaha Big Wheel 350, its suspension system was never meant for MX-style jumps. 
• Its tendency for obesity did not make it ideal for riders of all kinds and gave it the tendency to tip to the side more often than skinny-tire dirt bikes. Going two-stroke could have helped it shed off some weight.
• Changing its fat tire to match the rider’s preferred riding style was heavily limited by the 9-inch rim on the rear.
• Plus, the bike felt like an old truck with no power steering and posi-trac on the rear when riding on hard, level ground.

Despite not having Yamaha’s product line’s longevity, many riders still considered the Yamaha Big Wheel trilogy to be highly desirable. Many enthusiasts would not pass up the opportunity to own one of these collector-item bikes, giving it higher regard than current-production TW200 and Suzuki RV models.

Endearing Characteristics

If you ask BW’s avid followers, they would probably give you a long list of things they love about the Yamaha Big Wheel 350. Below is my attempt at consolidating what these enthusiasts have to say about the bike:

• Extremely powerful for its age and size and mostly starts with half-choke runs. Once warm, you can disengage the choke, placing the throttle entirely under your command.
• Revving from idle to the 8000-RPM redline is regular. Additionally, its humming engine sound is music to the ears for any motorhead.
• With an experienced rider, the BW350 is a pleasure to toss and apply throttle.
• Generally, turning is manageable and does not require a lot of force on the handlebars.
• The bike’s forward-inclined engine perfectly fits into the chassis, does not invade rider space. It is easy to maintain by doing oil, air filter, and other regular scheduled changes.
• Its large seating allows the driver to seat himself in many places and for different applications. It is upright with a relaxing handlebar reach for cruising. Likewise, tucking for extra aerodynamics is excellent on a straight line.
• The Yamaha Big Wheel 350 was the ultimate snow bike that can shred powder as much as it can shred dunes, giving snowmobiles a run for their money.

Only riders who have used a Yamaha Big Wheel will understand the joy of driving this fat-tire wheeler. Naturally, the list above is non-exhaustive. But even if it were, these attributes are plenty enough to want to own a Yamaha Big Wheel. It is not undervalued, nor is it above par. But it certainly is not a mediocre, mid-performance dirt bike. I guess you will have to own one to find out.

Big Wheel Questions

• What is the recommended fuel for the Yamaha Big Wheel 350?  The recommended fuel is regular gasoline. There is no specified Octane rating in the owner’s manual. Use gas with a pump Octane rating of 86+ and a research Octane rating of 91 or higher. Ensure that the fuel variant contains less than 10% ethanol and less than 5% methanol to avoid damage or performance issues.
• What kind of oil does a Yamaha Big Wheel 350 take?  The Yamaha Big Wheel 350 requires 1.69 quarts/1.6 liters of engine oil (disassembled), 1.47 quarts/1.4 liters (without oil filter replacement), and 1.37 quarts/1.3 liters (with oil filter replacement). The recommended engine oils are YAMALUBE 4 SAE 10W-30 SE motor oil or SAE 10W-40 SE motor oil. Again, there is no API classification indicated in the manual. But an ideal service classification should be SG type or higher, meet JASO MA standard, and not have Energy Conserving II labels.
• What is the Yamaha Big Wheel 350 worth?  The list price of the Yamaha Big Wheel 350 was $2,099 in 1988. Nowadays, some consider the dirt bike to be a collector’s item and sells for more than double its price at $5,099. These units are in pristine condition, with most of its parts still in stock form. Pre-loved moderately used BWs range from $200 to $935 based on Nada Guides data. Kelley Blue Book values are from $2,280 to $2,300 for units in good condition with typical mileage.

About Yamaha

Yamaha Motor Company Limited is a world-renowned leader in motorsports, off-road vehicles, personal watercraft, speed boats, and outboard motors, and is the maker of the Yamaha Big Wheel 350. This Japanese firm spawned the ATV industry in the ’80s. They continue to produce a wide array of life-enriching products and services that reflect its mission of creating Kando, which means feeling deep satisfaction and excitement when encountering something of great value. Yamaha strives to live by its shared values of innovation, excitement, confidence, emotion, and ties through its offerings worldwide.

Conclusion – Yamaha Big Wheel 350

Though short-lived, this iconic two-wheeler has made a lasting impression on the riding community. Its low ground clearance, powerful engine, oddly satisfying aesthetic, and funky rear tire are only some of the great features it offers. It was a magnificent creation at the right place but at the wrong time. Had it been built three decades later with today’s technological advancements, it would be one unrivaled dirt bike. Heck, it still is anyway.

Yamaha fanatics can only hope for a revamped version of the Yamaha Big Wheel 350 in the future. While that has not happened yet, let us be on the lookout for an opportunity to own one of these classic motorcycles.