All New and Improved Honda TRX450R

By Joe Tolle
Test Rider Cody Smith

How times have changed, remember the glorious 90s? The decade where manufacturers could sell the same outdated machines year after year without remorse.

Fortunately times are a changing. Heading into the 2006 model year the market is dramatically different now days. We’re now in the time and age where ATV manufacturers are seriously updating their existing fleet of aging machines. Now days they either update like they mean it or fall behind the times.

After updating the appearance and adding reverse to the 400EX last year, Honda went to work on more than half of their sport lineup for the 2006 season. With the competition updating their current existing high performance models and the rumors of more made for the track 450s coming soon, Honda figured it was time to advance their TRX450R.

Changes, updates, and technical stuff
When we arrived at Washougal the first question on our minds was when will we see a factory rig like this at the nationals?Honda put some serious changes into the 450R for 06. While the machine doesn’t look all that different, don’t let that fool you. There were small changes throughout the entire chassis, but the most dramatic changes were in the motor department. This motor has a lot more in common with the CRF450X dirt bike than it does with its 05 predecessor.

First up for 2006 is the offering of two models, electric and kick start. Both models are identical with the exception of a little weight difference and the parts necessary to give the electric start model that magic little button. Claimed dry weight on the kick start model is said to be 357lbs, while the electric start model weighs in at 363lbs. While it sounds like the kick start model has gotten heavier from last year’s claimed dry weight of 350lbs, Honda says that they are just trying to put out a more accurate number this time around. In all actuality, Honda has taken steps to lighten the machine for 2006. Be sure to really think out which 450R you want before you purchase. Honda says converting between the electric and kick starting unit will be quite expensive and Honda isn’t planning on offering a conversion kit.

For 2006 the rear of the 450R features a 15mm longer swingarm and new linkage settings. Rear suspension travel has been lengthened from 9 inches to 9.3.		Honda went to great lengths to keep weight down on the TRX450R. Check out the trick stainless steel header pipe and silencer.

Most of Honda’s most dramatic performance enhancements come in the way of the motor. With the same bore and stroke as the CRF dirt bikes, a cylinder and head that are virtually straight off the CRF, higher lift cam, a new 12:1 compression short skirt piston, and a new 40mm FCR carburetor, the Honda’s hits harder and revs faster at all RPM levels. Of course, power is still Honda smooth.Similarities between the TRX and CRF motor begin with the bore and stroke, (96.0mm by 62.1mm). The cylinder head is very similar to that found on the CRF450X. While valve sizes have remained unchanged from last year, (36mm intake and 30mm exhaust) the intake poppets are now made of titanium instead of steel for less weight and quicker revving. The unicam engine now revs to 9850 RPMs. Honda has chosen to stick with the single cam setup due to its light weight. The intake lob actuates two 36mm titanium intake valves, while the exhaust lob actuates two 30mm steel exhaust valves via a forked low-friction roller rocker-arm. A higher profile cam than last year, combined with head porting designed specifically for the 450R allow the engine to breath deeper

At the heart of the motor is a new short skirt piston. As with most of the other new parts on this engine, the new piston is lighter and very similar to the piston found on the CRF dirt bike. Compression has been raised from 10.5:1 to 12.0:1. According to Honda, the forged three ring piston is lighter than conventional designs. This allows the motor to rev higher with better cylinder sealing for better high RPM power.

One of the largest performance upgrades to the TRX motor is the 40mm FCR carburetor. Many serious TRX450R riders tossed the old carb and switched over to the CRF450 in the past. That expense won’t need to be taken this time out. Honda’s new flat slide design features a throttle positioning sensor for crisp throttle response. There are four rollers on the flat slide designed to make throttle action light. All this means more air in the new carburetor’s diet. In addition, Honda equipped the TRX with a completely new free-flowing air-box, with a 1.4 times larger air filter.

For 2006 you have the option of electric or kick start models. Choose carefully before you buy. Converting the electric start model, or vice versa will be quite expensive and Honda is not planning on offering a conversion kit.

Beefier A-arms, solid spindles, beefier steering knickers more rigid hubs, and improved camber settings highlight the chassis changes on the front end. The front shocks have been stiffened a bit, but wheel travel remains the same at 8.4 inches of travel.To reduce weight, Honda uses a magnesium cylinder head cover along with a stainless steel header pipe and silencer. A lighter radiator with revised fin pitch was used to increase cooling. There is also a fan for extra cooling. All these cooling revisions have allowed Honda to remove the oil cooler for 06, further saving weight.

After complaints about the 450R’s gear ratios in 2005, Honda gave the 450R closer gear ratios for 2006. The new gear ratios are said to make the 450R a better trail and track machine and are a better match for the machine’s revised power characteristics. Although the TRX shares many more engine parts with the CRF dirt bikes, the gear set is still wider than those used in the bikes. This is done in order to deal with the extra loads put out by an ATV.

To complement the machine’s engine overhaul, Honda went to work to sharpen the TRX handling. Starting up front, the Honda has stouter A-arms, solid spindles replace hollow ones formerly used, as well as tougher steering knuckles. New tougher front hubs were also installed to make the make the front end more rigid. To further sharpen the steering precision, the upper ball joints were moved in slightly, which is said to increase positive wheel camber. This was done to prevent the wheels from switching from positive to negative camber as the front suspension goes through its stroke. Negative camber is when the tops of the front wheels lean slightly outward, opposed to the slight inward lean that you are used to seeing. Negative camber causes unwanted front end push and less precise steering. In other words, negative camber bad!

Out back Honda extended the cast aluminum swingarm 15mm, (roughly 1/2 in) with a new linkage, which was revised to work with the longer swingarm. This 15mm extension seems quite conservative, considering that most aftermarket manufacturers recommend a +1 ¼ inch for racing applications. We think this subtle change was designed to keep a bit more weight on the front wheels during cornering, rather than as a wheelbase stretching race setup.

The 450R’s suspension has been updated front and rear. While front end wheel travel remains unchanged, the front shocks now feature a stiffer spring rate for more bottom resistance and to counteract the extra weight placed on the front wheels due to the longer swingarm. The front shocks now feature an aluminum spring preload adjustment reducing weight by 225 grams per shock. Out back, the rear shock was also lightened and suspension travel was lengthened from 9 inches to 9.3.

Wrapping up the changes to the 2006 450R is the machine’s ergonomics. In order to lower the rider’s center of gravity for improved handling, the rider’s seating position has been lowered 8mm, (less than 1/3 of an inch). As with all of the other changes to the Honda’s handling department, this is a very small change. While any one of these things would seem insignificant, we will have to see if all of the handling and ergonomic changes combined result in an improved handling package when we hit the track.

Ride Time
With the extra power on tap, the Honda is a more capable leaper. Check out Cody Smith as he takes advantage of the R’s airtime maneuverability. If you liked the 450R before, you are going to like it a lot more now. And if you didn’t care for it in 2005, try a 2006 model on for size. The electric starting model we tested fired right up whether it was in gear or in neutral. While it wasn’t an issue for our test rider Cody Smith, some cross country riders have complained that the electric model doesn’t want to start if you touch the gas at all, making dead engine starts in cross country races a little tricky. For motocross or casual trail riding, we couldn’t fault it.

Early on in the day, the differences between the 05 and 06 engine were immediately evident. This motor feels racier. The motor still pulls from bottom to top, but cracking the throttle at any speed or RPM level is met with a quicker more authoritative response. Where whacking open the throttle on the 05 stocker resulted in a torquey power surge, the motor on the 06 feels a lot more willing to wind up and respond. With a motor based on the CRF, the all-new FCR carb, higher compression and all of the extra air and fuel moving through the motor, it’s no surprise that the motor performs better. If you get the feeling that the engine is plugged up and will further benefit from opening up the intake and exhaust, you’re correct. Honda is claiming a whopping 30% increase in horsepower with the installation of their HRC power up kit, giving the machine a whopping 50 hp at the rear wheels! Your friend will be upset to discover that he will have to spend over $1500 to make his 05 450R as fast as your 06 with the $359 HRC kit installed. This is very impressive. We plan on testing the HRC kit in the future.

Dropping over 20 feet down this hill, the Honda did a fine job of soaking up the hit with Cody’s 150 pounds on board. Heavier riders can still tax the R’s suspension on hard landings. The suspension is a bit better for motocross but still retains much of the supple feel that makes the R such a great trail machine in stock form.One of the biggest problems on the 05 450R was the gear box. First and second gears were both too high, making second gear starts difficult. Honda claimed that the gaps between the lower gears were close, and the track proves it. With a lower second gear and more power on tap, second gear starts are now possible. Cody rode the 450R all day and never found a hitch anywhere in the transmission’s new gear ratios. Shifting as you would expect is butter smooth and the clutch never faded, no matter how much Cody abused it. Bottom to top, the motor is far superior to its predecessor, with a lot more performance just waiting for you to tap into.

While handling has been improved, it’s not as dramatically different as the motor. Steering is as precise as ever. Perhaps it’s a bit improved over the 05 model, but we would have to ride both machines back to back to truly determine how different the two really are. It’s not night and day different for sure. Still, the machine goes exactly where it’s pointed. Steering is light and there are no signs of under or over steer. Although the machine can cut an inside line, the bubble tires combined with the tacky track surface at Washougal demanded that you either scrub a lot of speed, or take the smooth outside line. The tires that Honda uses for compliance on the trails don’t lend themselves to aggressive cornering. Switching to any lower profile sport tire will make a big difference in the R’s cornering stability.

The Honda is a precise cornerer. Unfortunately getting through the turns quickly requires breaking the back end loose to keep it on all four wheels. Too much traction will result in two wheeling. Ditch the stock tires and you will eliminate much of this problem.

A much more capable engine, awesome brakes and typical high quality construction highlight the Honda’s strengths. Still, we would like to see a swingarm long enough for racing applications and tires with a bit less rollover. Considering the huge improvements, we’re not complaining.The new rider position is virtually impossible to detect unless you are extremely familiar with the 05. Lowering the seat height 8 mm is only one of many small changes made to the Honda to improve its cornering manners. At less then a third of an inch, it is hardly noticeable. If you found the old TRX450 comfortable, you’ll still feel right at home on the 06.

At 150lbs, Cody never taxed the suspension on the R. To Cody, the suspension felt, “smooth and never bottomed hard.” Heavier riders who don’t land as consistently spot on as Cody does will find it bottoming out from time to time however. Honda claims that they stiffened the front shocks and extended the rear wheel travel 3/10 of an inch.

While the front end felt a bit stiffer, it doesn’t seem as though it has gained that much bottoming resistance on big impacts. On a machine of this caliber, we would like to see a dual rate or more progressive front spring setup.

This would allow the machine to remain plush on small bumps and still have something left over for the big hits. Still, the suspension works well. It is a bit happier on the track, yet retains most of its plush ness that made it work so well on the trail.

 It’s easy to keep the front end up and the suspension does a good job of absorbing repeated impacts without packing down in the travel.Attention to detail is abundant on the TRX450. Fit and finish is first rate as with all Honda products. All of the controls operate smooth and precisely. The only thing that takes some getting used to is all of the engine noise. The exhaust is so quiet that you hear everything that is going on inside the engine. No, it doesn’t sound Cannondale clunky but it takes some getting used to. The brakes on the other hand take no time to get used to. They are phenomenal. They are progressive and have enough power to stop a small freight train.

Like we said earlier, if you liked the Honda before, you’re going to love it now. With a more potent engine, that has way more hop up potential for less money, choosing the 450R is now a more physically and financially sound decision than it was in the past. Sure if you’re serious about racing it, you will still have to set up the chassis and suspension as with the other machines in the high performance class, but the 2006 TRX450R will be more competitive than ever right off the dealer’s floor.

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