The 1988 Yamaha Terrapro is among the most useful innovations of the 1980s. Unknown to many, this utility quad pioneered the lineup of belt-driven and differential-equipped vehicles we enjoy today. The mower could be removed to convert it into a fun, recreational ATV. During workdays, attachments could transform the Terrapro back into a utility vehicle that would take care of tall grass and young saplings.
Produced from 1987 to 1988, the Yamaha Terrapro goes down in history as the first and only ATV to have power take-off (PTO) capabilities. Featuring a 350cc 4-stroke engine, hydrostatic transmission, and locking rear differential, this quad proved to be ahead of its time.
Like the Big Wheel 350, Yamaha created the Terrapro with the right intentions but at the wrong time – 30 years too early. Had it been produced later, given liquid-cooling and 20-hp power output at least, it would have smoked 500-class ATVs with its versatile application. But even with its primitive tech and fan-cooling system, this riding mowing machine is still considered the best vehicle of its kind. Intrigued? Continue reading to learn more about this vintage four-wheeler.
Among Yamaha’s First
The Yamaha Terrapro was 10th in the line of Yamaha off-road vehicles since the US release of the Tri-Moto, and 6th in the line of four-wheelers produced in the ’80s before the 1988 Consent Decree fully sealed the ATC ban. Sandwiched between the ’87 Big Bear 350 and ’88 Blaster, the Terrapro was the only quad with power take-off capabilities. This one-of-a-kind feature allowed the wheeler to use a wide array of Yamaha Terrapro attachments. Among them were rough-/finish-cut mowers, tillers, agricultural sprayers, post-hole diggers, and more.
While enthusiasts remember the iconic vehicle for its versatility, what made the Terrapro truly unique was that it was Yamaha’s very first utility vehicle. Its design and mechanism may very well be the archetype for the present-day Ultramatic V-belt transmission and a limited-slip differential. The biggest reason this does not seem to register with many off-roaders is due to the machine’s single-year production. Its ATV scene stint was so short that consumers have never even heard of the vehicle in some parts of the US and other countries. Not only did this impact the machine’s popularity, but it also made finding replacement parts a challenge.
Despite Yamaha Terrapro parts being pricier and claim that working on the quad is nightmarish, many avid supporters and enthusiasts attest to and defend the reliability of the quad. Riders growing up in the early ’90s learned how to mow their lawns on that bad boy. Owners claim only replacing a clutch cable, brake pads, and a fuel cutoff valve since purchasing it brand new in ’87. Like any other off-road beast, the Terrapro is loyal and will last many years when treated and maintained well.
Yamaha Terrapro Specs & Features (YFP350U)
- Engine: The Terrapro uses a four-stroke, air-cooled, single-cylinder SOHC engine. The forward-inclined power mill has a bore-stroke ratio of 83 x 64.5 mm, and the engine displacement is 349 cm3, with a compression ratio of 8.6:1 and a wet sump lubrication system. A Mikuni BTM32SH carburetor handles the air-fuel mixture. The engine is completely covered and has a fan that forces the air over the fins for cooling. The Yamaha Terrapro’s maximum power output is 14.5 hp/10.81 kW @ 5,000 RPM.
- Drivetrain: Power travels via a 5-speed hydrostatic manual transmission with high and sub-low 2WD. It has a thumb-control throttle and a lever that controls the gas (like a tractor), and a kill switch that works only when the PTO is engaged. PTO runs off a belt and, depending on attachment, may require an RT-38, FM-48, B-15, or RC-42 variant. The quad also has a rear differential lock that prevents the machine from tearing up the grass. The differential lock is located on the left side and looks like the same level as the choke by the ignition switch.
- Ignition: The Terrapro is brought to life by a DC-CDI electronic ignition with a kick start system. It also has an AC-magneto generator system and requires a 210-CCA (Cold Cranking Amps), 12V battery with dimensions of 5.31 x 3.54 x 6.57 inches (135 x 90 x 167 millimeters – L x W x H). Spark plugs are NGKD8EA Part# 2120.
- Tires – AT22 X 8-10 front and rear tires mount on tubeless cast steel rims. Carlisle All Trail II ATV Tires (view on Amazon) are excellent replacement tires in case of tire wear. They are also great for increasing acceleration and improving handling and cornering on days when you take off the mower and take out your four-wheeler for an adventure ride.
- Brakes: Right-hand operated front drum brake and a right-foot operated rear drum brake provide the Terrapro stopping power. Yamaha Terrapro parts should be similar to that of the Moto-4 YFM350ER or the ProHauler. Check with your nearest dealer for compatible brake components for your quad.
- Suspension: This hunting and workman’s bike is the first to feature a rear differential lock and swingarm rear suspension. Keep rear wheels greased to prevent them from seizing and making turns difficult.
There are very few resources that provide complete specs and maintenance information on the Yamaha Terrapro for free. Search results would not even provide overall vehicle dimensions. If you happen to own this quad, get a Yamaha Terrapro Service Manual (view on Amazon). It’s handy for first-line troubleshooting and order replacement parts and rebuild kits for your quad.
Terrapro Price and Expectations
Nada Guides only shows retail pricing (and not the MSRP) for the Terrapro – between $375 and $2,700. Auction listings value the classic blue machine between $180 and $2,735. Typically, a Terrapro in good working condition would include an operable transmission with Hi, Lo, and PTO speeds and add-ons like a seed spreader or a brush hog. Sellers would usually declare attachments (if any). Among the most common ones are the FM-48 Mowing Deck (SN: 2035) and the RT-38 Roto-Tiller (SN: 480).
Expect the ATV to have undergone minor home repairs and some broken knobs, worn handgrips, bent cargo carrier, torn seat cover, and bent or crusted footpegs. Be ready to shell out a few bucks as some of these preloved vehicles may need hydraulic work. Stock rings may require replacement as well. However, this should not be concerning, as a set of rings from any other 350-cc ATV should work – as long as the bore-stroke ratio match. It is rare to find a Terrapro with shiny plastics and a rust-free frame, let alone less than 1,000 hours.
Yamaha Terrapro Problems
Considering that the vehicle is 33 years old, it is only natural for owners to run into a few issues. But its single-year production, difficulty in securing replacement parts, finding Terrapro-savvy mechanics and dealers, and comprehensiveness of its service manual make attempts to fix its problems a tad too challenging – for the beginner rider, at least. Since not everyone is an experienced off-roader, I have listed below top Terrapro issues to help the nouveau owner out:
Differential Not Locking in Place
A tell-tale sign behind this malfunction is if the lever switch is not working right, accompanied by the wheels spinning nonstop. Pulling out the lever switch and resetting it will do the trick. Doing this is pretty simple if you know what to look for. However, learning it if you have never seen the lever switch before is the hard part.
Thankfully, we have online tutorials like this video by Ray Wallace demonstrating how to do a locking differential repair on this mowing monster:
Difficulty in Shifting to Reverse
You may notice that when you fully depress the foot brake with all your weight and pull back on the lever, it will randomly not go down far enough or click. Or the clutch may not work in reverse or would not disengage. When these symptoms occur, check the spring-pulled cable coming off the rear brake pedal, and trace it towards the shifter. In most cases, you will find the cylinder at the end of the retracting cable bent. This happens quite often as the cylinder can easily get caught on the housing’s lip, preventing it from shifting. If this does not turn out to be the probable cause, it could be due to the vehicle sitting for too long.
Rear Brakes Not Working
The most common reason your rear brakes will not work is if they are bone dry. To fix it, you will need to add the appropriate brake fluid then bleed the brakes. Doing these steps will show if you have any leaks in the sealed system. If these first two steps do not work, then you probably need to manually adjust the brakes forward to bring them within range after adding fluid.
Some owners do struggle with shifting on the Terrapro. Sometimes, the cable frays, causing rough shifting. Should you encounter this problem, pull the shift cable loose from the casing and try the lever to see if it moves freely. If so, it would indicate that the problem is with your shifter and cable. Getting a new cable will resolve the issue. Many PTO, clutch, and throttle cables are for sale on online reseller sites like eBay and Amazon.
Will Not Run in High
There are several scenarios where your quad may not run in high, namely:
- When PTO is engaged
- With the differential locked
- With towing implements
Getting this problem outside of the said scenarios require you to narrow down the issue, which typically traces back to an electrical problem, an electrical safety cutoff, insufficient fuel supply, or a broken switch (located near the two-point hitch on the rear). Should the culprit be a broken switch, this can be cut off and shorted together with the use of spade connectors.
Another thing worth looking into is the speedometer, as it has a magnetic reed switch that sends a signal to the CDI that prevents over-revving of the engine. If that reed switch is not working, the CDI will erroneously think that the engine is sitting still and will cut out instantly at higher speeds. You can test a reed switch along with a speedometer rotation. Similarly, an implement safety switch will prevent the PTO from engaging if nothing is hooked up. Pushing the governor throttle forward without any towing implement will also kill the engine.
Bypassing safety switches on the Terrapro is one of the many solutions proven to resolve the vehicle not running in high. Watch this video by Ray Wallace for a detailed demonstration of how to get things done:
A world-renowned leader in motorsports, off-road vehicles, personal watercraft, and outboard motors, Yamaha Motor Company Limited began as a piano manufacturer in 1887 before venturing into automobiles, speed boats, and all-terrain vehicles. It was not until a decade after World War II that the Japanese firm parted ways with its parent company to concentrate on motorcycle production, hence becoming Yamaha Motor Co., Ltd. To date, the maker of the Yamaha Terrapro is known for spawning the ATV industry in the ’80s and creating breakthrough, life-enriching products, and services that reflect its mission of creating Kando.
Conclusion – Yamaha Terrapro
Despite its limited time in the ATV scene limelight, the Yamaha Terrapro was able to make a lasting impression not only with adventurers but more so with hardworking farmers and ranchers. Its low ground clearance, three-point hookup, strangely satisfying bodywork, and practical fitments are only some of the features that folks simply cannot get over. The Terrapro was such an impressive innovation, with the sole drawback of being created at the wrong time and introduced to consumers who did not know any better.
The good thing is that consumers nowadays have grown more knowledgeable in maximizing all-terrain vehicles’ inherent capabilities and taking care of these vintage machines, and using them for the purpose they serve. And while it has been three decades since the birth of the ultimate farm ATV, the riding community and general public continue to look forward to Yamaha and other big ATV manufacturers to come up with a utility vehicle as practical but twice as powerful as the Terrapro.