Where credit's due:

Words: Andrew Boss
Photos: Richard Seck (unless otherwise noted)
Editing: Editor 'arris


In the safe hands of CMG ...

The criteria for our long term 2003 Yamaha WR450F was simple: What’ll she do? Particularly in the hands of the everyday schmo’s of CMG.

Also in the CMG vein (and maybe more important), can we do things cheaply?

Hopefully we demonstrated how much fun a capable off-road bike like the Yamaha WR450F can be, as well as being cheap to run and/or race.

The normal pleasure of trail riding was doable at nothing other than operating cost, save for the installation of factory bash-bars. Supermoto racing required replacing the stock knobs with enduro rubber and ice racing meant fitting a set of prepped ice tires, a front guard and some minor jetting changes. Any other mods required? Nope.

Enduros or Hare Scrambles could be done with the bike as delivered. This fits CMG’s budget well.

On the trail or the track, we were never down on power for our class. The WR is a nice combination of solid power, excellent frame and competitive suspension. An exhaust note that won’t have the neighbours calling the police when you want to show the local kids a third gear power wheelie also compliments it!

All in all we had a hell of a lot of fun with the WR - I’m sorry to see it go.

What follows is a summary of our year in the care and feeding of a WR450.


Motor worked well but wasn't happy about cold starts and had to have the woodruff crank key replaced.

Knowing that wild-revving, five titanium valved, modern four-strokes are slightly more complex (i.e. pricey) than what you might find in an old XT350, frequent oil changes are important. With an oil capacity of 1.2L, clean oil is a must.

Oil replacements were done after every ride in severe conditions or every second ride in less severe conditions. Utilizing Yamalube 20W40 and Yamaha OEM oil filters, complete oil changes cost approximately $15. That’s cheap insurance. Unlike previous years, the exhaust header does not need to be removed and the hardware is easily accessible so you have no excuses to not treat your WR right! The whole routine can be done in the driveway in about 20 minutes.

All the changes were routine except when metallic filings were found in the oil following the Woodruff Key failure (see "the pushing bit" below). The crankcase was flushed with two quick oil changes and fortunately no detrimental side effects such as oil consumption or exhaust smoke were seen.


$5 well spent at the local hardware store!

The only accessories we installed were Yamaha’s Pro-Bend aluminum bash-bars with white hand protectors. It wasn’t until we went to install them that we realized that they didn’t fit on the stock bars! Turns out Yamaha’s accessory bash bars only fit on Yamaha accessory Pro-Bend bars.

Undeterred, CMG hit the local hardware store parts bin and solved the problem for less then $5 using threaded nylon reducers, threaded inserts and permanent Loctite.

The sturdy hand guard combo did bang a few trees saving me from booboo’s. In addition, the added rigidity saved the handlebars and levers in my more spectacular get-offs.

We also ordered Yamaha accessory clear plastic adhesive sheets to see if we could protect the appearance of the frame and such from the inevitable scuffing that all off road bikes receive. Unfortunately I waxed the bike prior to the installation and couldn’t make the damn stuff stick.

Maybe the remaining bits can be a gift for a CMGRC contest winner!


Mr. Boss broke CMG tradition by not coming last in the Supermotard round ...

In preparing for our Supermoto race, Machine Racing slipped on a pair of Pirelli Scorpions. A subsequent test day to get comfortable with the enduro rubber in the Ganaraska Forest was short lived.

1.2 Km into the trail I came upon an impassable section. Clutch in and idling, I tried to walk the bike backwards when it uneventfully stalled. Once turned around, I thumbed the starter button but got only whirring sounds.

Having almost killed the battery starting the WR at the start of the ride I assumed it was just weak. Kicking and kicking and kicking had me pouring sweat and occasionally pooping myself when the WR would let out an incredible backfire, accompanying flame from the exhaust and dead silence in the woods.

I pushed until my feet blistered when my saviour came in the form of a heavyweight, pot smoking chap on an XR600. He quickly dragged me by a rope about two feet from his rear wheel back to home base.

... and again, as part of Team-Ice CMG during the 6 hour ice endurance race.

Photo: Sheila Tang

That’s when I remembered hearing about the woodruff key failures on some WR’s. Turns out that on some 2003 WRs the fit between the flywheel and the taper on the crank isn't very solid. In some conditions, a kickback or rapid reversal of the crank can shear the woodruff key, sending ignition timing way out of whack and resulting in a no-start condition.

Yamaha advises this condition can occur during electric start. The bad news is if you're way off the beaten path and have a failure, you have to wait for a pot smoking saviour. Or, if you are savvy enough, pull side case cover, find the woodruff key and try to realign the rotor/ flywheel. It can save a lot of pushing.

The good news is that Yamaha’s Technical Service Bulletin outlines a procedure that uses high strength Loctite to increase the grip of the taper/ rotor combo. The procedure doesn’t take long, in fact the good folks at Machine Racing did ours while we waited.

Knowing that a large part of appeal for the WR450F is the happy button, we used the electric start at all times following the repair in May ’03. It held up to the all the abuse CMG could dish and never let us down again.

If you have an ‘03 WR450F check with your dealer to ensure you have been updated. For ’04, Yamaha has provided the WR450F with a modified crank, taper and flywheel.



Photo: Sheila Tang

The WR held up well despite a full season of thrashing good fun. Cosmetically, blue plastic that turns white when it bends stayed remarkably blue. Nothing snapped, fell off, leaked, spontaneously combusted or needed replacement from wear. Even the chain and sprocket set stayed original. Well done.

Cold weather starting was troublesome though. We never developed a tried and trusted cold start routine and I couldn’t get the bike to start in winter until Machine Racing re-jetted it for the ice racing. Other owners seemingly had cold start routines that served them well though.

Once warm, the hot start lever worked every time. That’s when four stroke singles are at their best, when they’re running!

Note - Keep an eye for the last article to do with the WR - A day at Clinton Smout's dirt bike school.


Yamaha factory bits (off their US site):

Bash Bars - US$69.95
Mounts - US$59.95
Splash Guards - US$25.95
Proper Bars - US$105.00 (that's why we went with Home Depot stuff)
Clear Guard Plastic Sheeting - US$11.95

Ice Racing bits:

Pair of studded tires - C$800.00 - C$1,000.00 (Giver Racing Products)
Front ice race guard : C$250.00 - C$350.00 (Giver Racing Products)
*Rear ice race guard: C$200.00 - C$300.00 (Giver Racing Products)
Rejetting work - C$100.00
Tether switch - C$69.95 (plus C$75.00 installation)

Super Motard bits:

Pirelli Scorpion tires -
(1) 90/90-21M/C 54H MT90AT - C$171.90
(1) 120/80-18M/C 62S MT90AT - C$196.98

*Will be required for next season.


Pirelli for the Scorpion tires.

The folks of the Halton Off-Road Riders Association - they are genuine characters and good guys.

Jen and Julian at Off-Road Cycle in Port Hope for helping to make the KTM comparison a reality.

Supermoto Canada for their co-operation and help making our Supermoto race a reality.

George Jones of Giver Racing Products (905-571-1862) for not only the use of the fantastic ice tires and tire guard, but also for allowing CMG to get out there and experience how much fun you can have on a motorcycle in the winter!

John Bickle for the use of the ice tire covers.

And finally to the gang at Machine Racing for prepping the WR whenever we need their help.

WR450F links:

RACING #1 Super Motard
RACING #2 Ice Racing Endurance

WOODRUFF KEY FIX (from dealer notification)

Affected models: All 2003 WR450FR models. JYACJ04W*3A000207~ JYACJ04W*3A003933

Symptom: After a lean kickback while using the electric starter, the engine either won’t start or runs erratically.

Cause: The woodruff key holding the generator rotor (flywheel) on the crankshaft has been sheared or damaged, resulting in incorrect ignition timing. This is possible because of improper seating between the generator rotor and the crankshaft taper.

Remedy: On all affected units (whether or not damage has occurred), lap the generator rotor taper to the crankshaft taper to ensure proper seating. In addition, check and, if necessary, adjust the carburetor to minimize the possibility of a lean condition. If damage from lean kickback has already occurred, replace the woodruff key.

Identification of work done: If the modification has been completed, there will be a punch mark at the front of the frame serial number (located at the headstock).