Honda TRX 700XX IRS Ride Test and Review

Honda has dominated in ATV market share over the years. It all started in 1969 when they invented a new way to hit the trails with their US90, (later called the ATC 90 in 1970). Those old enough to have started out in the three-wheeler era probably have many fond memories of the innovative ATC 200X, 350X and 250R. Honda later progressed into four wheeled ATVs, along the way it basically built the foundation of today’s ATV race scene on the back of its mighty TRX250R.

Fast forward to today, even in a sea of available quads, Honda continues to lead in market share. What’s more interesting to this, and annoying to its dealers, is the fact that they’ve been doing this without a big bore sport ATV in their lineup. Honda dealers have been begging for a new big bore model (as well as a SXS, but that’s another story). No doubt this was the weak spot in Honda’s line up. All the other areas are pretty well covered. Their 250EX with its SportsClutch is one of best beginner level quads of all time, and their TRX450R absolutely dominated the race scene in 2007, winning 10 professional ATV racing championships!

Honda’s sport quads continue to be the choice of many ATV enthusiasts world-wide. And it goes without saying, when Honda creates a whole new sport quad category, like they just did with their new TRX700XX, there’s going to be plenty of interested enthusiasts eagerly awaiting a chance to take it for a spin. This is where we come in. You’ll definitely want to try out Honda’s first large displacement Independent Rear Suspended sport quad for yourself. Until then, below is a detailed review that we compiled after Honda allowed us to ride the new XX at the Dumont Dunes Off-Highway Vehicle Area in Dumont, CA.

Engine
The heart of the XX is a 686cc dry-sump, liquid-cooled SOHC four-valve single-cylinder four-stroke engine, which traces its heritage to Honda’s Baja-dominating XR650R motorcycle engine. The 700XX engine uses a bore and stroke of 102mm x 84mm, which takes the cake as the largest diameter single-cylinder that Honda has ever mass-produced.

As you would expect the 700XX engine has been specifically designed for the rigors of ATV duty. A gear-driven counterbalancer is used to help neutralize engine vibration. The stroke is longer by 2 mm than its XR650 motorcycle cousin and its bore is 1.4 mm larger.

The XX piston features a slipper skirt design and it strokes through a centrifugally forged, 3.5mm-thick steel sleeve. A forged piston was used to handle the increased mechanical and thermal loads, and it also benefits from an underside shower of cooling oil shot from a jet that protrudes into the center of the engine case. Compression is 10:1. The combustion chamber utilizes a pent roof shape and is fired by a single, centered spark plug, which is fired by the machine’s electric start button.

The engine inhales through a foam air filter fitted in a 7.6-liter airbox. The Programmed Fuel Injection (PGM-FI) system draws fuel from a 3.6-gallon blow-molded, multi-layer fuel tank and delivers it via a single Denso injector through a 44mm throttle body. A Keihin Engine Control Module (ECM) manages both the fuel injection and the transistorized ignition. The engine exhales through a single long-tube header tuned for excellent low-end and mid-range torque without sacrificing top-end power. Gases are expelled through a muffler constructed of 128-grade stainless steel.

 

Coolant is routed through an aluminum radiator with a 28mm-thick core—the same core size as a CRF450R motocrosser. A special wire-mesh filter in the oil hose connector and a custom bend of the oil return pipe protects the oil from sloshing and aeration in its separate brazed aluminum tank. This dry-sump design eliminates the oil pan, which contributes to a shorter engine height and consequently a lower center of gravity.

Several enhancements are made to the engine to simplify its operation and enhance durability. An automatic decompression system is activated whenever the electric starter is engaged. The starter-motor housing is incorporated into the engine crankcase casting and a disc-type torque limiter minimizes shock to the starter mechanism.

Before we move on to the Chassis and Suspension we need to talk more about Honda’s centered chain drive system, which is an outstanding design as far as we’re concerned. It was designed with the goal of providing optimum power delivery without sacrificing handling. All the while it needed to do this without adding too much weight to the machine. At the end of the day Honda impressively solved a number of issues typically associated with an Independent Rear Suspension (IRS) machine. We feel Honda’s engineers rose to the occasion and delivered the best design since their eccentric chain adjustment system in the eighties, which is now found on most ATVs.

A compact, centered shaft-drive system similar to the IRS-equipped TRX680FA Rincon could allow the use of equal-length A-arm rear suspension, but it was ruled out for three reasons. First, a shaft drive and its corresponding differential are heavier than a simple sprocket-and-chain drive system and the IRS-spec’d TRX700XX needed to be lean and nimble. Next, shaft drive is not as efficient as chain drive when transmitting power, a decided negative for a high-performance platform.

Clearly chain drive was the solution. The problem: traditional engine side-mounting of the countershaft sprocket meant that the location of the rear sprocket and chain would intrude into the travel space occupied by the A-arms.

Is this not the most protected rear sprocket and brake mechanism you’ve ever seen? Double-wishbone suspension is ideal in an IRS setup because it offers longitudinal and lateral strength and rigidity, allows for smooth shock absorber action and provides optimal control of rear wheel travel at both low and high speeds.

By making the upper and lower A-arms as long as possible, camber changes are kept to a minimum as the suspension arcs through its travel. This translates to a more consistent tire contact patch when traction is at a premium.

The best way to achieve this is to attach the A-arms as close to the center-point of the vehicle as possible. But when a large sprocket and chain occupy the space needed for the movement of the A-arms, compromises must be made. If the A-arms are shortened so that their frame mounting points are outside of the chain line, significant camber changes occur when the suspension is fully compressed or extended, minimizing and moving the tire contact area.
The centered chain drive layout allows ample room for long travel suspension high performance suspension. Another approach is to lower and/or tilt the inboard frame mounts of the lower A-arms (reducing ground clearance) and utilize a single-beam I-arm as the upper locating link. But an I-arm is less able to resist the twisting and flexing forces exerted on it; indeed these forces can be transmitted to the rear shock as well, causing it to bind. A more radical strategy employed by some competitive machines involves attaching the upper I-arm at a point farther back and lower on the frame. “Tucking the tail” of the rear suspension in this manner results in a mechanical control angle (the plane of the rear control arm mounting points relative to the plane of the drive-and-driven sprockets) as severe as 15 degrees—5 degrees is optimal—which effectively shortens the wheelbase when the suspension is fully extended and lengthens it when the suspension is fully compressed. The result is a fore-and-aft pitching over undulating terrain that can significantly impede predictable handling.

.

Honda’s Centered Chain Drive System – Continued
It was clear to Honda’s engineers that a centered chain drive system was the solution because it allowed for the ideal length and placement of the A-arms. The first step was to move the drive sprocket from its traditional left-side position on the ATV. To do this the engineers designed an ingenious set of gears and shafts. First, a final-drive gear was attached to the end of the countershaft—where the drive sprocket is normally mounted. Then, the final-drive gear spins a final idle gear which, in turn, spins the final driven gear. (The idle gear is needed to maintain the counter-rotating direction of the drive sprocket.) The final driven gear is mounted to a shaft that extends inward toward the centerline of the ATV and on its end is mounted the drive sprocket. This amazingly compact gear unit locates the drive sprocket just 33mm to the left of the 700XX’s centerline, giving the chain a straight run back to the rear driven sprocket. (The rear disc assembly sits an equal distance to the right of the centerline.) The driven sprocket is affixed to a compact receiver to which the equal-length rear wheel axle shafts are attached via constant velocity (CV) joints. So configured, the centered chain drive layout provides ample room for the location and placement of the desired A-arms.

Another benefit of the centered chain drive system is the ability to employ longer axle shafts. In the same manner that the up-and-down travel of long A-arms is circumscribed in a relatively small arc, so too is the effect with longer wheel axles. The positive benefit of minimal wheel axle travel is that the CV-joint angles are never extreme, thereby reducing power-robbing friction and the build-up of life-sapping heat.

A centered chain drive also contributes to the TRX700XX’s mass centralization. When a rider initiates a turn, the ATV rotates around its roll axis—a fore-and-aft horizontal line drawn through the center of mass of the ATV and rider. Placing the major masses (engine, fuel, rider) closer to this roll axis results in an ATV that reacts more quickly and smoothly to control inputs at the handlebars. Centering the chain drive and moving the A-arm mounting points, CV joints and rear disc assembly as close as possible to the 700XX’s centerline contribute to the application of the principle.

Honda’s centered chain drive system is a brilliant solution to an engineering problem that has puzzled designers of sport ATV IRS systems for years. By applying sound principles and some common sense in an effort to achieve an uncommon solution, we feel Honda, with their new patented centered chain drive system, has pioneered a very impressive invention for IRS equipped ATVs.

Chassis/Suspension
The frame of the TRX700XX is constructed of steel with a removable sub-frame. Independent double-wishbone front suspension uses steel A-arms and shock absorbers featuring two single-rate springs per side. This application of dual springs, a first for Honda, separates the function of each. Both the main spring and the short top spring (second spring) are single rate. Bottoming resistance is provided by the heavier main spring and the top spring adds compliance over small bumps. Together, they achieve what a progressive-rate single spring could have accomplished, but in a lighter, more compact package that takes full advantage of the 10.5 inches of useable suspension travel. Front preload is adjusted with screw-type adjusters. The A-arms are attached to aluminum steering knuckles, which in turn bolt up to aluminum hubs and 10-inch diameter aluminum wheels fitted with 21x7R-10 Dunlop radials.

The aforementioned independent double-wishbone rear suspension, made possible by the innovative centered chain drive system, features steel upper and aluminum lower A-arms. The upper and lower A-arms pivot on sealed needle bearings at the frame and support aluminum knuckles via oil-less bushings. The knuckles attach to steel hubs, and the 11-inch-diameter aluminum wheels sport 22x9R-11 Dunlop radials. The reason for steel hubs: greater resistance to side impacts and side loads. These steel hubs weigh less than an aluminum hub with the same strength characteristics. A non-adjustable rear sway bar attached to the frame and lower A-arms controls excessive roll without compromising the independent action of the IRS. Piggyback reservoir shocks provide 9.3 inches of fully usable travel and feature screw-type preload adjusters. Braking action is supplied by a hydraulic single piston squeezing a 200mm disc. The rear brake assembly is mounted on the rear sprocket receiver and is situated 33mm right of the 700XX’s centerline—symmetrically opposed to the location of the sprocket/chain assembly to facilitate equal-length A-arms and drive shafts.

An interesting outgrowth of Honda’s goal to fit the longest A-arms and axle shafts possible is the use of special 11-inch-diameter rear wheels (larger than competitive designs). The larger-diameter wheels allow the knuckles and hubs to reach farther into the wheel cavity, which effectively extends the A-arms and axle shafts to the perimeter of the 700XX’s track width. To maintain strength and light weight, the thickness of the rear-wheel wall varies as it extends from the center plate to the outer ring of the wheel—another Honda ATV first. And here’s another: the fitment of replaceable rim scrapers to remove mud and debris from rear wheels, a feature pioneered on Honda’s popular Foreman and Rincon series.

Body
The TRX700XX has one of the most modern-day looks we’ve ever seen. At first we couldn’t stand the looks of the front end, but the design is slowly growing on us. Honda provides two colors options; Metallic Black/Silver and Metallic Black/Red. A polyethylene push bar is used in place of an aluminum one. As much as we like new innovative ideas, we’re thinking an aftermarket aluminum bumper is needed. The plastic push bar may be strong but with nothing much to grab it’s hard to pick the quad up and out of a silt bed. Speaking of plastic, polypropylene rear A-arm protectors and high-impact urethane frame and engine-case protectors are used in an effort to protect the undercarriage. Honda saved a lot of weight in this. If this new armor choice holds up it could be the next big thing in undercarriage protection.

Rounding out the body and looks department is the cowl-integrated headlight with dual 30-watt bulbs and a highly visible LED brake light is also included.

Ride Test
The XX will feel at home over rocks and uneven terrain. An interesting note worth mentioning is Honda’s new one-year warranty plan, which has never been done until now. First we’ll define the type of rider this interesting new ATV is designed for. Honda tells us that this quad is a “category killer” and their target is people using utility ATVs aggressively as if they were sport machines. We can agree to some point, but after riding the machine, we’re thinking this is more of a desert racer’s dream quad than anything.

Hopefully you’ve read the pages ahead and you too see the potential Honda’s new XX truly has. Unfortunately the ride we were expecting in stock form won’t happen without the help of the ATV aftermarket industry. With some tweaking however Honda’s long awaited new big bore sport quad has some series potential.

Engine
The biggest single cylinder Honda has ever produced makes its power up high leaving a huge gap in low and mid range torque. Mid range power is decent, but still lacks that hit you expect in a high performance sport quad, especially one packing this many CCs. Up high the four-valve single-cylinder four-stroke engine comes alive and pulls nicely. It’s fast, but seems a little slower than Yamaha’s Raptor 700R.

Honda may have detuned their XX in order to meet California Emission Standards. If so the lack of get-up-and-go might be helped by eliminating the hindrance with aftermarket EFI mapping and ignition modifications. But in stock form, with no snappy power, you’ll need to clutch and rev your way to the meat of the powerband. This gets old and tiring after a while, so uncorking the XX with an aftermarket exhaust and EFI mods is an absolute must.

Transmission
Honda has a reputation of producing bullet proof transmissions. The 700XX performed very well as we expected. Honda is known for bullet proof transmissions. As we expected the 700XX 5-speed with reverse transmission worked without flaws. Shifts were right on the money. Gear ratios however seemed a touch off. There seemed to be a void between second and third gear. This may be greatly improved with an aftermarket exhaust and EFI mapping mods however.
Braking
Brakes are typical Honda in that they work just like they should. As with the chain the rear brake rotor and single piston caliper is extremely protected from the elements. In fact you could probably land on a rock and not damage the chain or the rear brake mechanism.

Ergonomics
Moving around on the 700XX is possibly the easiest of any quad. The quad’s front fenders are tucked away from the rider’s legs and the seat forms nicely around the gas tank allowing for a softer place for your knees. The seat is large and easy to move around on but lacks padding for long rides. It’s more of a sporty stiff seat like you might find on an older Yamaha YFZ.

Desert racers will want to increase the padding. Peg location seemed just about right as did the handlebars and controls.

Idiot lights, as they call them, conveniently let you know when you’re in neutral, reverse and overheating. The keyed switch is on the right fender as is the reverse lever.

Suspension and Handling
At 508 pounds this quad isn’t meant to be thrown around or jumped. That’s why we were surprised at how well it soaked up landing from jumps. Never once did it bottom out. It was actually a fun experience to land on one rear wheel, especially since this is something we’ve grown up trying to avoid.

What wasn’t fun was wringing out the XX in a long whoop section. As well as the quad did on landings it gave up in handling.

We so badly wanted a trophy-truck-like ride where the machine just floats along as the suspension effortlessly swallows everything up, but this just wasn’t the case. The rear shocks felt stiff, this is why the machine didn’t bottom from big landings. Perhaps a longer wheelbase and some replacement shocks are all that’s needed in order to tap into the huge potential lurking within the 700XX.

If the high ground clearance isn’t enough to protect you from rock damage, Honda’s says their new high-impact urethane engine and skids plates will. Steering the XX in low speed situations is just as tough as not stalling it. This isn’t necessarily a faulty design on Honda’s part; it’s more of an IRS physics problem. It’s give and take with an IRS ATV. IRS will be your best friend when charging down a hill that’s riddled with rocks and tree ruts, but you’ll need to give up a little when cornering. You see, both tires are always planted firm on the ground trying to drive the machine forward – so unweighing a rear tire in order to make a sharp corner is nearly impossible. The only way to quickly corner on the XX is to ride the machine aggressively, — using the throttle and clutch to reduce traction in the rear thus sliding and carving your way through the turn. Thankfully the low profile Dunlop radials did a good job of not rolling over, which would have made the whole turning situation much worse. But unfortunately, we did notice the front end tended to push. This could be amplified in good traction situations, which would be out of place in the sandy-desert areas where we feel this quad will excel.

In short, for those wanting to unleash the suspension and handling potential lurking inside Honda’s first-year-XX effort aftermarket help will be needed.

Overall Impression
There’s no putting around on this machine. It wants to be ridden hard and aggressive. If you’re a new rider that wants to trail ride on something different, you need to ride this quad before you buy it. In stock form low speed maneuverability is horrible as the IRS quad will push instead of corner and with no bottom and mid range grunt you’ll need to constantly clutch and rev your way through the trails. Our point is to keep all this in mind if you’re a Sunday afternoon trail rider.

In stock form we just don’t see this as a good choice for tight woods riding or perhaps GNCC racing out east. But if you’re a high performance desert racer on the west coast, with a little aftermarket help, there isn’t a better machine available.

2008 TRX700XX Specifications
Model – TRX700XX
Engine Type – 686cc liquid-cooled SOHC dry-sump single-cylinder four-stroke
Bore and Stroke – 102mm x 84mm
Induction – Keihin PGM-FI with a 44mm throttle-body fuel-injection system
Ignition – Full transistorized with electronic advance
Starter – Electric
Clutch – Manual
Transmission – Five-speed with Reverse
Driveline – O-ring–sealed #520 chain

Suspension
Front – Independent double-wishbone with dual single-rate springs; 10.5 inches travel
Rear – Independent double-wishbone with piggy-back reservoir shocks; 9.3 inches travel

Brakes 
Front – Dual hydraulic 174mm discs
Rear – Single hydraulic 200mm disc

Tires 
Front – 21x7R-10
Rear – 22x9R-11
Length – 71.5 inches
Width – 45.9 inches
Height – 44.7 inches
Seat Height – 32.7 inches
Ground Clearance – 10.2 inches
Wheelbase – 49.6 inches
Curb Weight* – 505 lbs.
Fuel Capacity – 3.0 gallons
Colors – Metallic Black/Silver, Metallic Black/Red

*Includes all standard equipment, required fluids and full tank of fuel—ready to ride.
For highly experienced riders 16 years of age and older.

2008 TRX700XX Unique Features
– All-new 686cc SOHC liquid-cooled fuel-injected four-valve single-cylinder four-stroke engine.
– Double-wishbone, Independent Rear Suspension (IRS) with tuned swaybar.
– Centered chain final drive system.
– In-gear starting in Forward or easy-to-use Reverse.
– Piggyback rear shocks with adjustable preload.
– Dual-spring front shocks with adjustable preload.
– 11-inch-diameter rear rims with removable mud scrapers.
– Radical new-style bodywork.
– Available colors are Metallic Black/Silver and Metallic Black/Red.

Engine/Drivetrain
– 686cc SOHC, four-stroke engine generates the highest peak output in its class.
– Liquid cooling provides consistent engine operating temperature in extreme conditions for maximum power and long engine life.
– PGM fuel-injection system with 44mm throttle body for excellent cold-weather starting, lower maintenance and consistent performance at high altitudes.
– Gear-driven counterbalancer minimizes engine vibration for smooth, comfortable all-day riding.
– Maintenance-free automatic cam-chain tensioner.
– Closed-crankcase vent system safeguards against engine oil contamination.
– Full transistorized ignition with electronic advance.
– USDA-qualified stainless-steel muffler/spark arrester for quiet operation and maximum power.
– Heavy-duty clutch stands up to Sport-ATV demands.
– High-efficiency dry-sump lubrication system features large-capacity oil tank for maximum engine cooling.
– Rugged five-speed transmission with Reverse has components and ratios specifically designed for Sport-ATV use.
– Unique, centered transmission with its direct-line chain final drive allows optimum IRS double-wishbone A-arm design.

Chassis/Suspension
– Independent double-wishbone front suspension uses premium shock absorbers featuring dual single-rate springs that allow a lighter, more compact package with 10.5 inches of fully useable travel.
– Independent double-wishbone rear suspension, made possible by the innovative centered chain drive system, features steel upper and aluminum lower A-arms. Using piggyback reservoir shocks, the system provides 9.3 inches of fully useable travel.
– Steel frame with removable subframe is extremely durable and strong.
– Triple disc brakes for excellent stopping power and weight savings.
– Special, large-diameter 11-inch aluminum rear wheels allow for ideal CV joint angles and A-arm lengths, resulting in superior power delivery, optimum suspension action and improved durability.
– Radial tires with knobby pattern provide superb traction and cornering ability.
– Durable, heavy-duty O-ring–sealed drive chain.
– Easy-to-use dual snail-cam eccentric chain adjusters.

Additional Features
– Engine design meets current (CARB) off-road emissions standards.
– Convenient pushbutton electric starting.
– Sculpted, plush seat provides excellent comfort and superb sport riding ergonomics.
– New and uniquely aggressive sport styling.
– Cowl-integrated headlight with dual 30-watt bulbs — distinctive sport style and excellent function.
– High-visibility, long-life LED brake light.
– Easy access to washable two-stage large-capacity foam air filter.
– Tough, polyethylene push bar up front and polypropylene rear A-arm protectors.
– High-impact urethane skidplate protects frame and engine cases.
– Rear mudguards with rigid footrests.
– 8AH maintenance-free battery.
– Keyed ignition switch offers added security.
– Simple-to-operate multifunction handlebar switch.
– Left-hand-operated parking brake.
– Tool kit includes tire-pressure air gauge and owner’s manual.
– Transferable one-year, limited warranty; extended coverage available with Honda Prot. Plan.
– Purchase of a new, previously unregistered Honda USA–certified unit by an individual retail user in the United States qualifies the owner for a one-year complimentary membership in the Honda Rider’s Club of America® (HRCA®).

Visit hrca.honda.com for more details.

Tags:

Comments

comments