Honda TRX450R

Honda TRX450R

    The Lake Whitney MX Track was an ideal location to test and ride the new 450R. Although this track is off limits to ATV’s, Honda made arrangements to use this track for the week. The track is well laid out and was perfect for testing the 450R. Table tops, drop offs, doubles, whoops, and step ups abound on this track. Beginner riders could have a blast navigating the track and the more advance could get all the “air” they wanted.

    The heart of the 450R is an ATV specific built high-tech, liquid-cooled four-stroke single-cylinder engine with a bore and stroke of 94mm x 64.8mm creating a displacement of 450cc’s. Cooling the big engine is accomplished with a big aluminum radiator with thermostatic controlled electric fan. The TRX engine uses the same type of “Unicam” as the CRF engine. A single camshaft activates the intake valves while a forked roller rocker arm operates the exhaust valves. Eliminating an exhaust camshaft and gear, and the added chain to drive those, cuts down on the weight on the upper end of the engine. Keeping the weight down as low as possible is a high priority on ATV racing quad. The cast piston has a short skirt at 28.4mm, but has 3 rings for added longevity. The piston sleeve is a Nikasil© liner which saves weight and permits closer piston-to-cylinder clearance for cooler operation for better engine life and consistent power output. You will find a needle bearing on the big end of the connecting rod, for maximum rpm and durability.

One of the interesting features of the 450R engine is the vertically split crankcase. The TRX engine uses a twin wet-sump design to separate the transmission/clutch oil from the crankcase oil. This allows the owner to use two separate kinds of oils in the same engine. Now your clutch oil will not contaminate the crankshaft/camshaft oil with burnt friction material. Added baffles in the cast design of the engine keeps everything lubed up even when riding on uneven terrain.

Forget about electric start, this is a performance quad! The forward rotating kick starter makes for easy starting of the big bore quad. With a built in auto compression release, one smooth forward kick is all that’s need to fire it up. A “hot start” lever is conveniently mounted on the left handlebar to assist in starting the engine after its warmed up. A 42mm Keihin Carburetor will provide plenty of wide-open power and a throttle position sensor will help maintain accurate response throughout the rpm range. Honda made the clutch easy to service by using a removable clutch cover. We can easily see aftermarket billet anodized covers coming

    Under that shiny red plastic you will find a totally new designed frame. Made of round tube steel with an aluminum sub frame it has been highly refined for maximum strength and handling. The sub frame is easily removed for easy access to the engine and rear suspension. A one-piece cast aluminum swingarm is light but strong and the Pro-Link© rear suspension system features new linkages and ratios developed specifically for the 450R’s ultra-sport suspension. The left side countershaft bearing and axle carrier feature double row bearings for added durability. Showa shocks are used front and rear with 8.4 inches of travel up front, and 9.0 inches on the rear. All shocks feature fully adjustable remote reservoirs. The front shocks have the reservoirs turned to the rear for added protection. On some brands of shocks you will find the adjustment does not really do much from one of the adjustment to the other, not on these shocks. Small turn increments are all that’s needed to make any needed changes to tailor the ride to your liking.

    On the front end of the double wishbone style a-arms are 174mm disk brakes with twin piston calipers. An innovative hybrid brake line system combines flexible CR style hoses with zero expansion steel lines to produce stopping power. The new brake lines and adjustable reach lever make the braking feel excellent. At the rear is a 190mm disc with oversize single piston caliper. All calipers are constucted with aluminum for reduced weight.

After many hours of testing tires, Honda decided Dunlop’s were the best all around tire for the rear, but the front tires are an all new design, specifically for the 450R.

The shiny plastic is all new for the 450R. Up front you will find dual 35watt headlights for excellent night time viability. Rubber grommets holding the nose section on allows for easy removal and access to the major electronic components. On the rear is a trick looking LED tail light/brake light. We can imagine how many of these tail lights will find there way to other quads.

    A welcome change from other models is a removable seat that is separate from the rear plastic. Under the seat is the tool kit and the air box. Under the removable air box lid is a standard foam type air cleaner element. As previously mentioned, the engine oil is split into two reservoirs. Different types of oil can be used, if so desired, on each side. The right side oil, circulated by a mechanical oil pump, has an easily accessed paper oil filter. The left side, clutch side, uses the splash method of oiling the clutch discs and transmission gears. They can be individually drained and replaced as necessary. The oil capacities have been increased from the CR engine design because of the added strain of the quad weight, and also because of the different attitudes the quad engine will be running in. This design utilizes an oil cooler and no external oil tank is needed for engine cooling.

When you finally get to ride the 450R you are going to realize the wait has been well worth it. Honda has put a lot of R&D into this quad in an effort to make it the best. The ride and handling are second to none. We rode the 450R on the track, some trails and also some nice tall hill climbs. It never let us down. In the air the R is very predictable and we noticed no bad habits, it’s a good jumper. The shocks are easily adjusted for rider preference and unlike some adjustable shocks, these adjustments do work. The front tires keep the R headed right were you point it and the rears have just the right amount of traction to power slide you through the turns or propel you off the jumps. The frame and suspension geometry are based on the legendary 250R with new refinements and improvements. Handling is spot on, just like you would expect from Honda. The quick revving 450cc engine has plenty of power and we are sure the aftermarket companies are hard at work to make it even better. The front end seems light and nimble and the “wheelie” riders will have no problems getting the front end airborne.

    HRC (Honda Racing Corporation) is going to market a “hop-up” kit for the 450R. This will include a more open air box lid, differnet jetting, camshaft, air box snorkel and removal of the muffler baffle. After riding the hopped up version, we think it will be definitly worth the roughly 0.00 list cost. There was a noticeable difference in the power of the two quads, and it adds a deep throaty sound to the quad.

2004 Honda TRX450R Specifications

Engine Type	450cc liquid-cooled single-cylinder four-stroke
Bore and Stroke	94mm x 64.8mm
Compression Ratio	10.5:1
Valve Train	Unicam; four valve
Carburetion	Keihin 42mm with throttle position sensor (TPS)
Ignition	CD with electronic advance
Starter	Forward kick
Transmission	Five-speed
Final Drive	O-ring sealed chain
Suspension-Front	Independent double-wishbone with Showa shocks, featuring adjustable spring preload, rebound and compression damping; 8.4 inches travel
Suspension-Rear	Pro-Link with single Showa shock featuring adjustable spring preload, rebound and compression damping; 9 inches of travel
Brakes-Front	Dual hydraulic 174mm discs with twin-piston calipers
Brakes-Rear	Single hydraulic 190mm disc with single-piston caliper
Tires-Front	22X7-10 knobby radial
Tires-Rear	20X10-9 knobby radial
Length	72.6 inches
Width	46.3 inches
Height	43.6 inches
Seat Height	32.6 inches
Ground Clearance	4.2 inches
Wheelbase	49.2 inches
Dry Weight	350 pounds
Fuel Capacity	3.2 gallons
Color	Red