The Honda ATC250R was the greatest high-performance three-wheeler ever produced by a big-name manufacturer. It was the perfect racing prototype created in such an inopportune time – only half-resurrected by the TRX250R, its four-wheeled successor that inherited its suspension and engine design.
The Honda ATC250R (or Big Red 250R) launched in 1981 and was the first to strengthen the foothold of ATCs in racing. Featuring Pro-Link suspension, an Enduro-Harley Davidson front aesthetic, and a 70 mph top speed, the ATC250R was tough and fast.
The Honda ATC250R had so much more to offer other than solidifying the presence of ATCs on the racetracks. Its durability, build quality, and performance made the wheeler appealing to the riding community and consumers in general.
Read on and discover more about the specifications, improvements, and mod ideas surrounding Honda’s first high-performance all-terrain vehicle.
Last Big Red Standing
The Honda ATC250R was eighth in the line of all-terrain cycles released by Honda since the ground-breaking US90 made its debut in 1970. This racing machine introduced the market to a 248-/246-cc liquid-cooled powerplant, folding footpegs, and five and six-speed transmission options. These attributes were not commonplace on other ATCs at the time.
Together with the Big Red 250 and 250ES, the ATC250R was considered the holy grail of racing, created for recreation and competition. It was not until the mid-1980s that Honda diversified its product line to include utility-type machines for industrial and agricultural use.
Many of the improvements incorporated into the ATC250R were evident in the 2nd generation ATC250R (1983 Big Red 250R). Among them were a gear-driven counter-balancer that reduced engine vibration, 30-mm round-slide carburetor, dual disc brakes for stopping power, adjustable, air-assisted front forks, and a single, fully suspended gas-charged rear shock.
Wheel travel gradually increased across all three generations of the vehicle from 6.7/4.3 inches in 1981 to 9.8 inches in 1987. The 3rd generation ATC250R (1985 Big Red 250R) saw further enhancements in the powertrain, fuel delivery, and engine displacement.
Out of the Big Red series, the ATC250R was the only vehicle manufactured from 1981 to 1987. Its siblings – the ATC 250SX, the Honda Big Red 350 or Honda ATC350X, and the Big Red 200 or ATC200 trims – enjoyed only half the air time than it did with consumers.
A later version of the ATC250R, the Big Red ATC250ES, was sold outside of U.S. during the same year the Consent Decree was implemented. There are still a handful of these vintage rides in Canada, Australia, and Europe.
Honda ATC250R Specs & Features (1985-1987 Model)
- Engine: A longitudinally-mounted two-stroke, liquid-cooled engine with a bore-stroke ratio of 66 × 72 mm (2.60 × 2.83 inches) powers the vehicle. Engine displacement is 246 cm3 delivered by a 34-mm piston-valve carburetor and with a compression ratio of 8.0:1. It has a gasoline-oil mixture lubrication system with an oiled polyurethane foam air filtration. Fuel tank capacity is 9.8 Liters/2.6 US gallons with a 2-Liter/0.52-US gallon reserve.
- Lubrication: For top performance, use an SAE 10W-40 Honda four-stroke oil (ideally without graphite or molybdenum additives) or its equivalent. Depending on ambient temperature, you may also go for SAE 5W, 10W-30, 20W-40, or 20W-50 oil viscosities. The service manual recommends an API service classification of SE/SF or higher. But since that API grade is now obsolete, you may use SJ or higher. Make sure it meets MA JASO T 903 standard.
- Drivetrain: A six-speed constant mesh transmission and a wet, multi-plate type clutch system powers the wheels and is handled by a 520 O-ring chain (13/39). This powertrain combo, coupled with a race-ready chassis, made the ATC250R more suitable for top-flight competitions.
- Ignition: It has a fully-transistorized, CDI primary kick-starter system. A 14.5V alternator with a rated output of 159 watts @ 5,000 RPM powers up electronic accessories. It requires a 12V 10Ah, 185-CCA (Cold Cranking Amps) battery with assembled dimensions of 5.9 x 3.4 x 5.2 inches (L x W x H) and requires an NGKBR9ES /NGKBR8ES spark plug. A NOCO Genius G4 6V/12V 4.4 Amp 4-Bank Battery Charger and Maintainer (view on Amazon) will help keep your 12V battery in tip-top shape.
- Tires: Stock tires consist of 23 x 8-11 front tires and 20 x 10-9 rear tires mounted on steel wheels. Recommended tire pressure for the front is 4.3 psi/30 kPa (0.30 Kg/cm2) and 3.6 psi/20 kPa (0.20 Kg/cm2) for the rear. Replace stock rubber with Kenda Bearclaw K299 ATV Tires (view on Amazon) for better grip on sand, deep mud, snow, or uneven terrain.
- Brakes: The brake system consists of dual-pot single hydraulic discs for both front and rear. Inspect the brake system frequently to ensure there are no fluid leaks or parts deterioration. Should you need to replace the brake pads, do so in pairs. Additionally, you must bleed the hydraulic system once it opens or if the brakes feel spongy.
- Suspension: The Honda ATC 250R suspension system features a 250-mm telescopic fork at the front and a 250-mm swingarm Pro-link rear linkage, and compression and rebound adjustable shock. Trail length is 37 mm with a caster angle of 21°30′. The engine assembly mounts on a semi-double-cradle steel frame.
- Dimensions: Overall dimensions are 75 x 44.5 x 42.7 inches (1,905 x 1,130 x 1,085 mm – L x W x H). The vehicle wheelbase is 51.4 inches/1,305 mm. Dry weight is 131 Kg/289 lbs. Weight distribution is 52.5 Kg/116 lbs at the front and 78.5 Kg/173 lbs at the rear, exclusive of rider weight and accessories.
- Exterior: It comprises a steel frame and plastic body material in white, blue, or red with a blue seat cover. The location of the fuel tank is at the front, right below the handlebars. A 55-watt pod headlight provides the trike superior light distribution. Getting an aftermarket pipe and silencer for your ATC250R exhaust will help improve your trike’s performance by up to 5 hp while ensuring that you stay within local sound limits.
Price of the ATC250R
The suggested retail price at launch for the Honda ATC 250R was between $2,205 and 2,298, depending on the model year and features. Nowadays, this three-wheeler cost could range from $225 to $600, depending on previous maintenance. Auction listing prices are within the $350-$4,000 range – cheap resales are mostly in poor condition or not running at all. These units would be perfect buys if intended as a project build.
Improvements Post 1981
To aptly compete in the dirt-bike dominated world of the early 1980s, the ATC250R had to undergo cosmetic, design, and performance changes. Below is a summary of those developments:
- The addition of drilled rotors and hydraulic disc brakes at both rear ends
- New headlight design and engine shut-off switch.
- New styling, chassis, and head pipe
- Longer suspension travel for both front and rear
- Pro-Link rear suspension
- Extended wheelbase for improved high-speed stability
- Narrower front tire for better steering accuracy
- Carburetor size increased to 30-mm
- Larger front disc brake and fuel tank
- Folding footpegs
- Slightly bigger overall dimensions
- Seat height increase by one inch to 29.9 inches
- Improved steering control
- Longer suspension travel than previous model years
- Telescopic forks increased by 4 mm in size
- Brakes received dual-piston calipers at both ends
- Smaller tires all around for better handling
- Improved ATC250R top speed from 60 to 70 mph
- Liquid cooling system
- Improved handling and ergonomics
- Slightly reduced dry weight
- The 34-mm round-slide carburetor changed to an oval-slide design (for improved throttle responsiveness)
Why Did Honda Stop Making the ATC250R?
Manufacturers had to cease producing ATCs (or trikes) due to safety concerns. The hazards that came with riding a three-wheeler were due to the engineering and lack of censorship in adolescents and children using them. When reported cases of ATC-related accidents, injuries, and deaths increased, the U.S. Justice Department had to impose the 1988 Consent Decree, which eventually led to a global production ban of all-terrain cycles (ATCs).
Reviving the Mighty ATC250R
The following modifications, and racing skills the likes of the legendary Mickey Dunlap, are guaranteed to bring back the ATC250R to its speed-demon stature:
Fitting a brand-new Hot Rods crankshaft (designed for a TRX250R) with no power valve into the ATC250R chassis not only provides a better rod angle but also breaks the rear end loose for sliding through turns. When used with a spacer plate, the setup allows more time to change ports, resulting in increased torque and better throttle responsiveness.
Similarly, professional cylinder porting/decking, head re-chambering, and piston/top-end gasket modification help the three-wheeler gain mid-range power. It dramatically improves the vehicle’s power curve and accessibility across the RPM range and boosts compression. Use a minimum Octane rating of 100 for your fuel moving forward.
Replacing the stock axle carrier with a billet-aluminum bearing housing and installing a racing axle help gain width, strength, and stability required for motocross. The billet housing comes with heavy-duty twin-row bearings. Similarly, the Pro Racing axle allows up to 3 inches of width adjustment for different track conditions. This maxes out the machine’s width per most ATV MX events. It also comes with a trick billet axle hub – some parts dealers include a lifetime warranty with the purchase.
Valve emulators work best with stock suspension, imitating a cartridge fork’s function and allowing the compression and rebound circuits to be tuned independently. You may need to pair this with a set of progressive-rate fork springs (which become much stiffer near the end of the travel), Chromoly rear swingarm, high-flow valve pistons, and custom valving.
In particular, the replacement swingarm features new needle bearings and twin pinch bolts on either side of the rear. This reduces carrier twisting and strengthening crack-prone areas of the stock swingarms.
A CR250 dirt bike’s ignition system will do wonders on the ATC250R. This setup features a lighter flywheel and a different ignition curve, which dramatically enhances the engine’s RPM buildup. The reduced flywheel weight works well with a pro-caliber engine build but may not be ideal for casual trail riding.
Ease of Navigation
The stock rubber that made for easy sliding consisted of a harder compound compared to modern MX tires. Unfortunately, the stock tires’ size (23 x 8-11) is a bit odd by today’s standards and hard to come by. If you want to convert your ATC250R into a motocross-capable machine, it is best to go with 18 × 9.5-8 tires. They have the height and width appropriate for motocross competitions and allow the back-end to break loose easily.
For your trike’s cockpit to have a modern feel, swap your old handlebars with Renthal handlebars (view on Amazon). Similarly, Ez-fit Nerf Bars (view on Amazon) would look better on your bike than the stock footpegs while providing superior traction and feel.
New aftermarket plastics, fenders, and radiator shrouds also restore the trike’s exterior to its former glory. Billet-center beadlock wheels offer security and add to the vehicle’s racy appeal.
Even with these improvements, the ATC250R will have some imperfections that will remain unaddressed. The relationship between the bars and footpegs not being suitable for taller riders, low seat height, and difficulty in ingress and egress, to name a few.
Still, completion of all these phases is sure to turn your ATC250R into the Racetrack King it once was. If you don’t find this build project challenging enough, an ATC250R missile kit/two-wheel conversion should be a more fitting task to undertake.
Honda Motor Company Ltd. began with a concept in 1946 with then mechanic, Soichiro Honda. Since establishing Honda Motor Company, the firm has grown from selling motorized bicycles with surplus engines to dominating the automobile market to participating in Formula 1 races. Soichiro dreamt big and made sure to realize his dreams one by one.
Thanks to Soichiro’s vision and unwavering hunger for excellence, the Japanese firm has become a world leader in various industries and automotive segments, including motorcycles, electric automobiles, and energy solutions.
Conclusion – Honda ATC250R
This iconic three-wheeler astounds riders as it did when it first appeared in the 1981 Baja 1000. Even after four decades, the trike is still quick enough to run circles around an MX dirt bike. It has enough grunt to pull riders up steep hills or out of corners, and reigns over trails as it does on tracks.
The fact that it remains to be a primary racing weapon of choice only proves the effectiveness of its highly-engineered performance and design enhancements. The Honda ATC250R lives on as the machine that changed a nation through sport, earning its well-deserved prestige and reputation.