Honda 2002 CRF450R - Model Overview


CRF450R
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2002 HONDA CRF450R
Model Overview
- Bike Available Oct. 2001 -

2002 Honda CRF450R
Specifications | Model Features

The future is now: Introducing the 2002 CRF450R

With the new 2002 model year, Honda is updating the technological state-of-the-art with a dazzling new four-stroke motocross racer--the CRF450R.

Powered by an innovative, high-tech liquid-cooled four-stroke engine, the CRF450R is now reality, not a rumor. The CRF450R has generated a whirlwind of anticipation, and for good reason. In its first-ever outing, it won the final round of the 2000 All-Japan National Motocross series. In doing so, the CRF450R has already proven its ability to win against the best two-stroke machines the premier 250cc class can offer.

This big advantage starts with big-time power, specifically 54 bhp and 34 lb./ft. of torque at 9000 rpm. Moreover, the designers of the CRF450R pared away grams wherever possible to establish new standards for light weight, with a claimed class-leading dry weight of 225 pounds. That makes the CRF450R the lightest mass-produced four-stroke motocrosser ever created, and gives it a power-to-weight ratio that has been the sole domain of two-stroke motocrossers.

With a bore and stroke of 96mm x 62.1mm for a displacement of 449cc, the four-stroke CRF450R engine features an innovative Unicam valve train, which incorporates a carburized single camshaft that directly actuates two 36mm titanium intake valves. The camshaft's single exhaust lobe actuates two steel 31mm exhaust valves via a forked, low-friction roller rocker arm. The SOHC configuration and a separate cam holder contribute to a notably compact design, which allows a remarkably narrow, 21.5-degree included valve angle and saves 13.3 ounces over a comparable dual overhead cam design.

The titanium intake valves weigh only 24.8 grams each compared to 40.0 grams for a steel valve. Lightweight valves help create a high-revving engine, but with the CRF450R the primary focus was on saving space. A lighter valve permits the use of a smaller valve spring, which takes up less space so the camshaft can be set lower for a more compact engine and lower center of gravity. The steel exhaust poppets handle the 11,200-rpm rev ceiling just fine--wait until you hear this engine scream!

Valve adjustment is accomplished with shims; the intake valves use a direct, shim-under-bucket system, while the two exhausts incorporate shims between the rocker arms and keepers on the valve stems. The roller bearing on the rocker arm reduces friction and therefore wear, so the cam lobe can be narrower--and lighter--than usual. This compact valve arrangement also flattens the combustion chamber, allowing free flame propagation and a high compression ratio of 11.5:1. The forged, double-ring piston is stunningly short, with an ultra-mini skirt; it measures 96mm in diameter, but it's only 33.6mm tall and amazingly lightweight at only 261 grams--114 grams lighter than a piston of convention design. This is cutting-edge stuff that comes straight from Honda's Formula 1 race car technology.

The CRF450R utilizes vertically split crankcases with a built-in oil pump to reduce weight 5.1 ounces over a conventional design, and the five-speed gearbox incorporates its own separate lubrication system, just like a two-stroke engine. Separating these systems makes for a smaller oil pan, less weight, and less power-robbing oil drag around the crankshaft. In addition, the oil bath surrounding the eight-disc clutch will be subjected to a lower heat load.

Other trick parts include a flat-slide carburetor with bearings; the slide runs on ball bearings to reduce the throttle pull resistance. Dual radiators provide effective heat dissipation, and a lightweight titanium head pipe leads to a stainless steel exhaust that terminates with a repackable aluminum muffler--quality components all.

In addition, the CRF450R frame is Honda's latest aluminum design, essentially identical to the new frame used on the 2002 CR250R. Although not interchangeable with the CR250 frame, the 450R uses the exact same concept and execution, with different engine mounting points and induction layout being the main distinctions. Specifically, the CRF450R incorporates the same weight-saving features, so it's less than half a pound heavier than the CR250R frame.

Up front, the CRF450R is equipped with a 47mm inverted Showa cartridge fork that includes lightweight aluminum damping rods for a 12.3-ounce weight savings over the previous-generation fork, plus 16-position adjustment for both rebound and compression damping. The 450 also features a Pro-Link single-shock rear suspension incorporating a fully adjustable Showa rear damper. This trick unit boasts 17-position rebound damping, plus separate low-speed (13 positions) and high-speed (3.5 turns) compression damping adjustments. Bottom line: expect the 450R's handling to set new standards among four-stroke motocrossers.

Honda's engineers also made easy starting a priority for the CRF450R. Big racing four-stokes are hard to start, but the CRF450R features several systems to ensure easy starting. Thanks to a small, lightweight and automatic kickstarter-actuated decompression mechanism and hot-start system.

The new racing season heralds a brave new world for motocross. By bringing to bear the formidable power of Honda's four-stroke engine technology and the aluminum chassis design, the designers of the 2002 CRF450R may have turned the racing world upside down--once again.

Color(s): Red Only
Available: October 2001
Suggested Retail Price: $6,299 (US)

FCRF450R Features / Specifications

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