What to Know About the Yamaha Big Bear 350: Specs and Full Review

The 1980s saw a lot of first-ever in the ATV community. As for Yamaha, this period became one of their most innovative as they witnessed a lot of milestones on their part. Among these were the Terapro, Warrior, and the Banshee, the latter two having made it in the roster of Yamaha’s best of the best. This period also witnessed the rise of the 4×4 ATVs, and that’s the section where the Yamaha Big Bear 350 shone brightly. 

First launched in 1987, Yamaha Big Bear 350 caught the attention of enthusiasts and consumers with its 4×4 capability, rugged aesthetics, and heavy-duty design. Equipped with a front-wheel torque control differential (TCD) and a Hi-Lo ten-speed automatic transmission, the Big Bear 350 was Yamaha’s excellent response against competitions like the Honda  FourTrax and Foreman. 

As a 348-cc all-terrain vehicle, this Big Bear appealed to people who engage in tough chores, namely in farms and ranches. Others claim that this quad performs fantastically for hunting. Regardless of the occasion or task at hand, the Yamaha Big Bear 350 is a mule regardless of the terrain. Whether you’re dealing with mud, shallow water, dirt, or hardpack, this ATV is a versatile ride that delivers according to expectations.

Furthermore, this four-wheeler had an entry-level design that made it an ideal starter quad, especially for those who were yet to learn how to ride an ATV. Its electric starter, reverse gear, and automatic clutch make the Yamaha big Bear 350 a convenient and easy-to-operate quad.

The Yamaha Big Bear 350 had a lengthy production run, which spanned from 1987 to 1998. During that period, Yamaha produced different trims, including two-wheel variants, both of which became a hit. By the turn of the decade, a larger and more capable 400-cc quad took the reins and spearheaded the Big Bear lineup.

What are the Different Models of the Yamaha Big Bear 350?

Production for the Yamaha Big Bear 350 spanned from 1986 to 1998, resulting in a good, lengthy thirteen-year run. At the same time, this four-wheeler made it on Yamaha’s list of best-selling quads—an achievement that directly translates to the Big Bear’s impressive performance. 

Apart from the base model, Yamaha also produced variants of the Big Bear 350, which had a 2WD driveline. These units joined their 4×4 siblings from ‘96 until its final year of production in ‘99. Furthermore, the manufacturer also released different trims of the Yamaha Big Bear 350, namely: the Hunter Edition (HT) in 1999 and the 2000 Big Bear 350 Special Edition. Below is a list of Yamaha Big Bear 350 4×4 models from the years 1987 to 1999.

On the other hand, the different 4×2 models of the Yamaha Big Bear are the following:

Meanwhile, this table contains the Big Bear 350’s Special and Hunter Edition models: 

How Much Does a Yamaha Big Bear 350 Cost?

The price of a Yamaha Big Bear 350 depends on the trim and year of the model. Of course, modifications and the quad’s current condition also dictate the cost of a unit. According to www.nadaguides.com, an ‘89 to ‘92 Big Bear 350 that is in excellent condition could fetch anywhere from $2,720 to $3,195, while a ‘94 would be around $3,485.

The table below contains the current suggested list price as well as the low and average prices of some of the Big Bear 350 models. These details are based on www.nadaguides.com.

What to Consider Before Buying a Mint Yamaha Big Bear 350?

Like most used ATVs, what makes a pre-loved Big Bear 350s tick is that they are reasonably affordable. As one of the bestselling quads back in its heyday, you will definitely come across these units, perhaps by the droves.

However, finding a used Big Bear 350 for sale is the easy part of the process. Checking one up close for signs of defects and other issues can become a challenge though, especially for beginners. Should you find yourself in the same position, the following tips below may provide you with some assistance:

1. Check the Tyres, Wheels, Shocks, and Joints
   • When inspecting the tyres, make sure that there are no cracks across the surface. A flashlight would be an ideal tool while you are on the hunt for any sign of wear. 
   • Make sure that the ball joints and bearings are in good condition. Unless you are looking for an overly dilapidated ATV, a worn wheel bearing is a surefire deal breaker. 
   • Check the shock absorbers for leakages. You would easily identify one by looking for any oily spots around the top of the shocks. 
   • The constant velocity (CV) boot is the component that prevents the grease from seeping out of a quad’s rotating joint. A worn CV boot means water and dirt could infiltrate and spell damage to the joint. 

2. Verify the Condition of the Lubrication/Transmission Fluid
   • Never forget to check the engine and gear oil of the quad you’re supposed to purchase. There are instances in which minor components get separated from their assembly and get sucked into the oil sump. In most cases, those crushed metal objects reappear in the form of tiny metallic particles clinging to the surface of the dipstick.

3. Inspect the Engine and Airbox
   • Check if there are signs of an oil leak, particularly from the head gasket or the valve cover. Unless you plan to buy a quad that’s in poor condition, there’s no point in purchasing an ATV with a faulty engine case.
   • A dirty air filter is a telltale sign of poor maintenance. Cleaning the filter does not cost much nor does the process take a lot of time. However, that dirty airbox sure does say something about the overall condition of the quad.

What Is the Top Speed of the Yamaha Big Bear 350?

The Yamaha Big Bear 350 has a recorded top speed of 40 MPH. Some owners report having gone up to 45 to 50 MPH. In such cases, we have to consider the condition and type of terrain which may contribute to the quad’s speed and overall performance. 

Installing mods and upgrades, like quality air filters and slip-on exhausts may help improve the Big Bear’s HP output. However, since this Yammy was designed to perform grunt work, such modifications could hurt the quad’s transmission or clutch. 

Specifications and technical Features of the Yamaha Big Bear 350

Engine

The Yamaha Big Bear 350 sports an oil-cooled, four-stroke, single-cylinder, single overhead cam engine. Also, the quad has a bore of 83 millimetres (3.26 inches) and a stroke of 64.5 millimetres (2.54 millimetres). The BST34 Mikuni carburettor delivers the correct amount of fuel and airflow mixture into the 348-cc engine, enabling the quad to produce a compression ratio of 8.6:1.

Fuel

This four-wheeler only uses unleaded gas with a pump octane number (PON) of 86 and up or a research octane number (RON) of 91 and up. If you are to use gasohol, make sure it contains no more than 10% ethanol, and that it does not contain methanol. The Yamaha Big Bear 350 has a fuel tank capacity of up to 10 litres (2.6 US gal) and a reserve tank of 1.3 litres (0.34 US gal).

Ignition

This quad has a direct current-capacitor discharge ignition (DC-CDI) system, which is activated with a push-button electric start switch. The Big Bear 350 also has a mechanical recoil starter which serves as a backup should the CDI malfunctions for whatever reason.

In addition, a CDI magneto generator system provides power to the Big Bear’s electrical accessories. The Yamaha Big Bear 350 requires a GM14AZ-4A with a voltage of 12 volts and a capacity of 14 Ah. As for this ATV’s spark plug, you may use an NGK D8EA or a DENSO X24ES with a gap of 0.6 ~ 0.7 millimetres (0.024 ~ 0.028 inches). 

Lubrication

The Yamaha Big Bear 350 uses a wet sump lubrication system and has an oil capacity of 2.9 litres (3.1 US quarts) for a periodic oil change. If the oil filter needs replacement, the required oil would be 3 litres (3.2 US quarts). The total amount of engine oil should be 3.5 litres (3.7 US quarts).

This all-terrain vehicle uses Yamalube 4 as a lubricant with a viscosity grade that is dependent on the outdoor temperature. Therefore, you may use either SAE 5W30, 10W30, or 20W40. Make sure it has an API Service of SG, SE, SF or higher. As for the final gear oil, SAE 80 API GL-4 Hypoid gear oil should be used. Hypoid gear oil with GL-5 and GL-6 ratings are also acceptable. 

Transmission/Drivetrain

As a semi-automatic rec-utility vehicle, the Big Bear 350 has a constant-mesh, five-speed forward transmission, inclusive of a reverse gear, with a centrifugal, wet-type, automatic clutch system. The shifter has a left-foot operation. 

With the spur gear and the shaft drive acting as the vehicle’s primary and secondary reduction systems, respectively, the quad has a primary reduction ratio of 76/24 (3.167). Its secondary reduction ratio, on the other hand, is 26/26 x 24/18 x 33/09 (4.888). The table below contains the Big Bear 350’s gear ratios for its gearing.

Suspension

An independent double-wishbone front suspension and a swingarm rear suspension with a monocross design provides the Yamaha Big Bear 350 with a superb suspension design. Both the front and rear suspension systems come with coil spring/oil damper shocks, which ensure 150 millimetres (5.9 inches) of wheel travel, as well as spring preload adjustments. 

Brakes

A single-disc hydraulic front brake and a mechanical rear drum brake make up this ATV’s stopping mechanism. The former is right-hand operated, while the latter is operated with the left-hand lever or the right-foot pedal. 

In addition, a parking brake also provides stopping power to the quad, especially while on an inclined surface. This braking mechanism can be activated by lowering the lock plate after operating the pulling the left-hand lever. 

Tyres

The stock Yamaha Big Bear 350 is fitted with a pair of KT404 Dunlop AT 25 x 8 – 12 front tyres and a pair of KT405 Dunlop AT 25 x 12 – 9 rear tyres. The manufacturer’s recommended tyre pressure is 25 kPa (0.25 kgf/cm², 3.6 PSI) for both the front and rear tyres. Moreover, the minimum and maximum recommended tyre pressure are 22 kPa (0.22 kgf/cm², 3.2 PSI) and 250 kPa (2.5 kgf/cm², 36 PSI), respectively. 

Dimensions

The Yamaha Big Bear 350 has a length of 1,945 millimetres (76.6 inches), a width of 1,095 millimetres (43.1 inches) and a height of 1,165 (45.9 inches). Additionally, this four-wheeler has a seat height of 835 millimetres (32.9 inches) and a minimum ground clearance of 245 millimetres (9.65 inches). With a wheelbase of 1,236 millimetres (48.7 inches), this Big Bear has a minimum turning radius of 11.1 feet, making it a considerably manoeuvrable vehicle. 

Capacity

This rugged all-terrain vehicle has a curb weight of 259 kilograms (571 lbs). The front carrier has a maximum load capacity of 40 kilograms (88 lbs), while the rear carrier has a good 80 kilograms (176 lbs). Apart from that, the Big Bear comes with a storage box located at the rear and has a load capacity of 2 kilograms (4.4 lbs). This workhorse has an outstanding 410-kilogram (904 lbs) towing capacity and a vertical trailer hitch limit of 15 kilograms (33 lbs).

External Features

The chassis of the Yamaha Big Bear 350 comes in a steel tube, frame-type design with a caster angle of 4° with a trail of 21 millimetres (0.83 inches). Along with a durable plastic body, the quad also comes with front and rear fenders and bumpers, utility racks, footpegs, and floorboards. 

Furthermore, this rec-utility vehicle has indicator lights for the neutral and reverse gears and oil temperature. Each indicator requires a 12-volt, 3.4-watt bulb. Also, the quad is fitted with two 12-volt headlights, each with a 25-watt capacity, as well as a 12-volt, 7.5-watt tail light. 

The Big Bear 350 has an easy-to-operate light switch and engine stop button on the left handlebar, including the parking brake lock plate and the rear brake lever. The throttle lever, speed limiter, and front brake lever are on the right side of the handlebar. The reverse knob is at the centre of the handlebar, directly adjacent to the indicator lights.

What Are the Pros and Cons of a Yamaha Big Bear 350?

Since its inception, the Yamaha Big Bear 350 became a blockbuster not just because of its 4×4 capability, which rivalled that of Honda’s Fourtrax series. With its TCD capability, the quad offers a smooth and plush ride regardless of the terrain. This aspect is one among many things that enthusiasts love about the Big Bear 350. However, this four-wheeler still falls short on some aspects despite being a remarkable quad. Below are the pros and cons of having a Big Bear 350.

Pros:

Versatile Transport Quad

The 4WD Yamaha Big Bear 350 is a purpose-built quad that’s meant to perform difficult farm and ranch chores. With its heavy-duty front and rear racks and considerable towing capacity, the Big Bear is literally quite a beast when used in accomplishing backbreaking work. Some owners can’t help but compare it to the Honda Rancher 4×4, which is also capable of handling gruelling grunt work. 

With this four-wheel-drive ATV, you can haul a farm trailer filled with bales of hay or farm equipment. Some owners also prefer this quad when hunting, especially when hauling wild game on the way back. 

Apart from that, Big Bear’s front TCD also makes a great ride along trails, snow, and mud bogs. This innovative feature makes the vehicle, not just an ideal multipurpose farming and hunting quad, but also a great four-wheeler for off-road adventures. 

Superb and Reliable Suspension Design

The Big Bear 350’s suspension system is what made it stand out among the rest of the 4x4s that existed during its time. The quad’s superior double-wishbone front suspension offers riders a smooth and pleasant ride. On the other hand, the monocross suspension provides better balance and manoeuvrability. Also, the ATV has ample wheel travel, thus ensuring optimal comfort while riding regardless of the terrain. 

Convenient and Beginner-Friendly

The Big Bear’s entry-level design is what makes the quad a fantastic ATV, especially for beginners. Its electric push-button starter and the dual-range, Hi-Lo ten-speed transmission, and centrifugal clutch system are just some of the Yammie’s conveniences that owners appreciate. Additionally, the reverse knob, which is located at the centre of the handlebar, is easy to use especially when in a bind. 

Additional Pros:

• High ground clearance, which enables the quad to travel across uneven terrain without a hitch 
• Availability of aftermarket parts makes modding and upgrading is easy for the Big Bear 350
• Outstanding ergonomics as the seat height is okay in relation to the position of the handlebars
• Its compact frame makes it an ideal ride, especially along narrow trails. 
• Later models, especially the 1999 4WD base unit has awesome rugged aesthetics
• Impressive steering capability
• Has impressive fuel economy
• Reasonably priced quad
• High carrying and towing capacity

Cons:

Problems with the Transmission

Some Big Bear 350 owners have complained of having transmission issues after having ridden the quad past its top speed limit of 40 MPH. However, such cases are often attributed to human error rather than a technical defect. 

As a utility quad, a stock Yamaha Big Bear 350 is not designed to run beyond its given speed limit. Modded or not, the quad may still experience transmission problems. 

Faulty Throttles in Earlier Models

OIder models, particularly second-hand units, may exhibit throttle issues, which causes the vehicle to perform terribly, making riders think that the vehicle is running lean. Veteran Big Bear owners, however, suggested warming the vehicle up before taking it for a ride. 

Typically, a broken or cracked carburettor and incorrect fuel-air mixture are some of the main causes of throttle problems. Installing a new carb kit could resolve the issue. Also, putting on new air filters or simply keeping them clean regularly may help. 

If you are planning on getting a new carburettor, you’ll be wise to get an OEM instead of the aftermarket version as the latter does not perform well as compared to their stock counterparts. If the carburettor is dirty, there’s no need to replace it; simply clean it with a carb cleaner.

Issues with Torque

Some riders have reported losing torque while in the middle of a ride. This problem is often associated with a malfunctioning carburettor, specifically a sticky or broken float bowl. A faulty spark plug may also play a hand in this dilemma. Performing regular checkups helps your quad in good working order. Consulting an ATV expert or mechanic would be ideal in fixing the problem in no time. 

Additional Cons:

• Front brakes tend to compress into the handlebar; often result requires a master cylinder rebuild kit
• Backfiring and popping noises in the engine which sometimes point to carb issues.
• Lack of power as a result of jetting problems. 

About the Manufacturer

Yamaha Motor Co, Ltd. is one of the leading producers of automotive engines, motorcycles, personal marine vehicles, and even ATVs like the Yamaha Big Bear 350. Founded in 1955, the Japanese firm is currently headquartered in Iwata, Shizuoka in Japan. Today, Yamaha is one of the largest corporations at the forefront of technological advancements on motorized products.

Final Takeaway — Yamaha Big Bear 350

Despite its shortcomings, the Yamaha Big Bear 350 remains a solid and reliable quad. Even with a top speed of only 40 MPH, this 350-cc mule makes up for versatility and other notable features, namely: towing 900-lb cargoes, traversing uneven trails, shallow water crossings, and mud holes, to name a few. 

Besides, the older models of the Big Bear make excellent rebuilding platforms, especially for first-timers, considering its entry-level design. Also, this workhorse has a compact frame and a terrific suspension, which makes this classic and iconic quad deserve credit where credit is due. With proper care and regular maintenance, the Big Bear 350 would make a fine off-road animal any time of the day.