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Priding itself as the first big-name ATV firm to go neck and neck with Honda, Yamaha was at it again. But this time around, the Japanese manufacturer did not create a racing model to challenge its long-time rival. It opted for a more relaxed, less intimidating machine with just enough power and grunt as it has tricks up its sleeve – something that would appeal to thrill-seeking, aggro-recreational riders. So in 1983, it launched the Yamaha 225DX.
The Yamaha 225DX (a.k.a. Yamaha YTM225 Tri Moto) was a sport-rec ATC that instigated the use of electric starters and shaft drives in all-terrain vehicles. With a robust engine and a slew of industry-leading features, this iconic wheeler was highly regarded as one of Yamaha’s greatest creations.
Not only was the Yamaha 225DX a forerunner of electric-start, shaft-driven ATVs, but it was also equipped with a 4-stroke engine – breaking the norm of all-terrain vehicle operation on all fronts. And although it was never meant to conquer the racetracks, more and more enthusiasts are recently discovering how efficient it is to ride on the dunes. If you are intrigued by the history and capabilities of this iconic wheeler, then this guide is for you.
Say Hello to Convenience
After only three years since launching the 1980 Tri-Moto YT125G, Yamaha introduced the public to yet another first – the Yamaha 225DX. First released in 1983, this three-wheeler takes pride in being the world’s first ATC to offer an electric start system and shaft drive.
Because of their level of ingenuity, these features catapulted the 225DX into the limelight. And as if these were not enough, the trike also featured telescopic front forks and a mono-shock rear suspension.
The 225DX debuted in the ATV landscape alongside the 196-cc Yamahauler (YTM200EK) and Tri-Moto (YTM200K) models. It was produced only for three years – between 1983 and 1985. Despite its short-lived run, the machine succeeded in creating a lasting impression with the riding community.
Functionally, it was Yamaha’s first-ever mass-produced recreational three-wheeler and its indirect response to Honda’s ATC250R.
Yamaha’s Tri Moto Series
While not bearing the “Tri Moto” name, the Yamaha 225DX is one of five iterations under the said series. In 1979, Yamaha first introduced the 123-cc, 2-stroke Yamaha YT125G, gradually increasing engine displacement with succeeding models.
Improvements were made along the way to the machine’s transmission, bore-stroke ratio, and speed/torque output (to name a few). Interestingly, the Tri Moto lineup began and ended with an air-cooled, 2-stroke engine – the last installment of the series being the Yamaha YTM225DRS Tri Moto produced in 1986.
Only 125-class versions of the Tri Moto were released between 1980 and 1983. It was not until 1982 that Yamaha launched the YT175J in multiple markets and exclusively in Japan’s Hokkaido region. 1983 seemed to be the busiest year for the product lineup, with several machines, such as the YTM200 and YTM225 models, being marketed simultaneously.
1984 Yamaha 225DX Specs & Features (YTM225DXL)
The Yamaha 225 DX uses an air-cooled, 4-stroke power mill with an 8.8:1 compression ratio and a bore-stroke ratio of 70 x 58 mm (2.76 x 2.28 inches) – slightly bigger than the YTM200K Tri Moto.
Piston displacement is 223 cm3 (13.6 in3) delivered by a Mikuni VM22 (later changed to a VM24SS, according to online sources). This carburetor was used across all year models (YTM225DXK/L/N) with the same #112.5 main and #60 pilot air jetting and lends to a Yamaha 225DX top speed of 40-60 mph (64.3-96.6 km/h, unofficial) and max torque of 16.5 Nm (1.69 kgf-m, 12.2 ft-lb) @ 5,500 RPM.
Fuel & Lubrication
Like other Yamaha Tri Moto models, the 225DX has a wet sump (pump) lubrication system mated to a high-quality foam air filter. Fuel tank volume is 2.4 US gallons, but neither reserve capacity nor Pump Octane Number is mentioned in the service manual.
The oil capacity required is 1.5 L/1.6 US qt. (oil change) or 1.8 L/1.9 US qt. (engine overhaul) of SAE 20W-40 or its equivalent. As an alternative, the manufacturer recommends same-viscosity motor oils without molybdenum or graphite additives. For temperatures below 40 °C/4 °F, use API-grade SJ+ SAE 10W-30 oils meeting JASO T903 MA standards.
A 5-speed constant mesh manual transmission and an automatic, centrifugal-type multiple-disc clutch assembly deliver power to the wheels. A recirculating ball bearing steering system and final shaft drive handle wheel spin. The shift sequence is all-up (N-1-2-3-4-5) and is not to be confused with the YTM225DR, which comes with a reverse gear.
This powertrain is revolutionary because it was the first in the ATV market to utilize the shaft drive. Compared to chain-driven wheelers, shaft-driven trikes require less maintenance and running costs. Regular chain adjustment and lubrication are not a necessity, making the vehicle easier to clean. Best of all, the shaft drive draws out the full potential of the Yamaha 225DX carb.
Ignition & Lighting
It has a CDI (Capacitor Discharge Ignition) and an electric start system with recoil backup. A 12V 14Ah/(10 HR) GM14AZ-4A battery, alternator, and solid-state rectifier/regulator comprise its charging system. Ignition timing is non-adjustable and set to 10° BTDC @ 1,000 RPM (initial “F” mark) or 30° BTDC @ 6,000 RPM (full advance).
Spark plug requirement is similar to the 1980 Tri Moto – an NGK DR7EA or ND X22ES-U spark plug with a 0.6-0.7 mm (0.024-0.028 inch) gap. The same goes for idle speed, which has stayed at 1,400 ± 50 RPM. Lighting specs include 45 W (headlight), 7.5 W (taillight), and 3.4 W (neutral and reverse).
If worn or damaged, you can replace the stock battery with either a YTX14AH-BS, YB12A-A, or YTX14AHL battery (view on Amazon) format. Make sure to use a battery retainer should you purchase an aftermarket battery with a slightly lower amperage than what is recommended by the manufacturer. Also, don’t exceed the specific battery gravity of 1.260 indicated in the manual when charging.
Tires & Brakes
Stock rubber consists of low-pressure tubeless 22 x 11-8 tires on all threes mounted on steel rims. Tire pressure recommendations for front and rear wheels are 15 kPa (0.16 kgf/cm2, 2.2 psi) but can be aired down or inflated within the range of 15-69 kPa (0.12-0.70 kgf/cm2, 1.8-10 psi), depending on the type of terrain. A front drum brake and enclosed rear discs complete the machine’s tire-and-wheel assembly.
Converting stock wheels to aluminum helps take the weight off the Yamaha 225DX, making it a tad lighter. Replace punctured tires with same-size Cheng Shin C829 Knobby Tires (view on Amazon) – perfect for traversing more technical trails.
As for the overall health of your tire-and-wheel assembly, make sure to regularly inspect the condition of your wheel bearings, tire tread, and rims. While you are at it, carefully examine the master cylinder, hoses, and caliper units for early signs of damage or brake fluid leakage.
The 225DX was one of the first to sport front telescopic forks and a rear mono-shock. This cutting-edge system provided the ATC with smoother maneuverability and improved overall handling over its competition. More importantly, it made for an impressive 8.1-inch ground clearance that worked well with the vehicle’s 45.3-inch wheelbase.
Length and width measurements of the 223-cc Yamaha DX are 71.1 x 40.2 inches (1,805 x 1,021 mm). Seat height is 28.3 inches (718.8 mm) and works for most physiques. Dry weight is 317 lbs (144 Kg) – a considerable mass for a 225-class machine and a potential dilemma for a novice rider stuck in the mud. Unfortunately, weight/load limits and GVWR figures are not in the service manual.
But based on the payload capacities of its same-class counterparts, it would be safe to say the three-wheeler can handle up to 200 lbs (91 Kg).
Standard features include Yamaha 225DX parts such as serrated footpegs, square headlights, a contoured, MX-style seat, handgrips, rear hitch bracket, black-trimmed rear fenders, and a high-clearance front beak. Its tubular steel frame is painted in black, matching the grips, fender trims, and seat. On the outside, the YTM225DXL and YTM225DR models look virtually the same – both trikes clad in Yamaha’s signature Competition Yellow. To tell them apart, determine which one has a reverse gear.
Yamaha 225DX 3-Wheeler Pricing
The list price for Yamaha 225DX ranged from $1,699 to $1,849 (‘83 YTM225DXK, ‘85 YTM225DXN), with the 1984 Yamaha YTM225DXL valued at $1,799 (at least $4,600 if sold today). This amount is representative only of base models and excludes accessories or any other type of add-on available through the dealership.
With its piston displacement merely a fraction behind Honda’s ATC250R, the three-wheeler was considered competitively priced and especially appealed to riders looking for a compromise between budget and performance.
Auction and trader site listings are not far from the original MSRP of the Yamaha 225 DX. Secondhand units sell for as cheap as $265 or as high as $1,000. Wheelers that cost below $300 are predominantly sold for parts or disused for extended periods. Others may be working intermittently or with minor to persistent problems – such as engine flooding or puncture-prone tires. Conversely, pre-owned machines in excellent working condition start at $735.
The 225DX Tri Moto Restomod
I have discussed restomod recommendations in length in an article I did a while back on the 1980 Yamaha Tri Moto. But for the benefit of first-time readers, I will go over tested-and-proven suggestions riders need to prioritize:
The stock Mikuni carb is quite restrictive and hinders the vehicle’s top speed, power, and torque output. This is why riders go for bigger carbs and performance exhausts like a Big Gun 07-1202 ECO ATV Silver Slip-On Exhaust (view on Amazon) to enhance the Yamaha 225DX’s speed rating and power delivery. A Timberwolf 250 powerplant is among the most popular carb swap choices for experienced ATC owners. Plus, its U-joint yoke snaps just right in place in the 225DX A-arm after minor adjustments. Retrofitting a carburetor from an old Big Red is another option.
Given its age, secondhand 225DX units can get pretty rusted due to the severity of use and moisture or dirt buildup. Thankfully, powder-coating and hydro dipping make it possible to restore the three-wheeler to its former glory. Prepping the plastics only takes a few steps. Just be prepared to spend between $600 and $1,000 (more for polypropylene plastics) if you decide to use both coating methods.
Although the Yamaha 225DX was one of the first ATCs to have a full suspension setup, there was still a lot to be had in this area. More experienced Tri Moto owners opt for a +3 swingarm, G-Force +2 Banshee hubs, Yamahauler rear-axle shaft, and YFZ450SE rear shocks to improve the machine’s suspension performance.
Furthermore, they pair these enhancements with corresponding tires and other front-end alterations that make the entire suspension system more robust and conducive to rough handling.
Smoking the Competition
Only true-blue Yamaha 225DX fanatics would understand and appreciate this pun. Honestly, I find it amusing that this statement can sum up the highs and lows of the famed three-wheeler. During its heyday, the small big shot outshined its 250-cc counterparts with the conveniences and performance it offered.
But at the same time, it was known for the trail of smoke that it always seemed to leave behind – a problem that continues to exist more so with secondhand 225 DX Tri Motos.
The Yamaha 225DX is a generally well-mannered, all-around trike. It has decent power, good suspension numbers, and offers a smooth, comfortable ride on par with Honda’s ATC 200X and 250SX bikes. Its shaft drive is exceptional and renders the machine almost maintenance-free.
Handling-wise, the 225DX is better in muscling its way through obstacles and mud than its larger-displacement competition and would have effectively bested the 250SX had it not been for the absence of a reverse gear.
On the downside, a pre-owned 225 DX may smoke horribly and have a burnt-out primary clutch. For some secondhand units, this issue goes away as soon as the vehicle operates more frequently. But if it does not, mechanical savants recommend honing the cylinder, re-seating the valves, and putting new rings and valve seals.
It is also wise to adjust the air-fuel mixture (if running rich) during the process. For more complex issues, there are sections in the service manual with detailed troubleshooting steps for resolving the problem.
Yamaha Motor Co., Ltd. (or Yamaha Hatsudōki Kabushiki-gaisha) is a world-renowned Japanese manufacturer known for its personal watercraft, motorized products, and ATVs. Originally an affiliate under then Nippon Gakki Seizo Co., Ltd., the firm parted ways with its parent company in 1955 to focus on motorcycle production.
Over time, it has grown its product offerings to include scooters, motor bicycles, engines, generators, and off-road vehicles such as the Yamaha 225DX. Yamaha has not looked back since and is now an automotive powerhouse with over 52,000 global employees and 132 consolidated subsidiaries.
Conclusion – Yamaha 225DX Review
The Yamaha 225DX may have been one of the most short-lived ATCs in off-roading history. But that did not stop this three-wheeler from breaking ground and shifting the entire industry’s course towards what it presently is. Nowadays, you will hardly find any ATV without an electric starter. Similarly, most big-bore behemoths excelling in their respective sub-segments equip a shaft drive that keeps repair costs down and makes vehicle upkeep a lot easier.
In hindsight, the 225DX could have benefited from a longer production run and further improvements to its suspension components. But given the technology and genius available at the time, the “Cadillac of the trails” was in its top form – so much so that it challenged industry leader Honda and other major ATV manufacturers to shape up and evolve.
The short stint of the Yamaha 225DX Tri Moto was more than enough to prove the machine’s worth as an unrelenting contender. And in doing so, it showed Yamaha’s resolve to take the initiative and take on the future.