Wr450F Model Year Changes


13 replies to this topic
  • YamaJet

Posted January 14, 2012 - 07:44 AM

#1

I've incorporated revisions and re-posting after site changes.

2003 WR450F First Year
The '03 was heavily based on the 400/426 but the basic engine was considerably lighter (discounting the electric starter)
Almost no parts interchange with older models except for wheels, forks, and triple clamps.
First year for the side access airbox.
The biggest change for the '03 was obviously the electric starter.
Automatic compression release
DC electrical system (requiring the use of a WR specific CDI)
Redesigned seat/tank that more closely match the YZ profile.


2004 WR450F changes
New cast Aluminum Kickstand
New Internal suspension changes
New crank, flywheel, and starter drive parts.
There was also a change to how the starter ring gear was located on the crank. '03 models had a washer that locateded on a machined step on the flywheel. '04+ machines did away with this and use a special bolt on the camchain buffer to limit movement of the starter ring.
New Kickstarter shaft. Diameter was increased from 18mm to 20mm.
New Clutch cover. Changed to accomidate the larger shaft.
Torque limiting idler gear assembly for the starter. This was the fix for the infamous "shearing of the woodruff key" problem that plagued the 2003 bikes.
The 2004 idle gear assy can be easily installed on the 2003s so if you are looking at buying a 2003 model, make sure it has this upgrade.


2005 WR450F Changes
New Lower Seat Height
New 48mm Kayaba AOSS (Air Oil Separate System) fork that separates the air and the oil. The 2005 did not have AOSS forks. They were new forks with 48mm stanchion tubes. The forks internally were nearly identical to previous models, using an open cartidge.
New triple clamps for 48mm forks (was 46).
New shorter Rear shock
New redesigned swing arm
New head was designed with a slightly lower compression ratio (12.5:1 to 12.3:1), the intake ports are 9% smaller, and the carburetor and ignition settings were also tweaked to provide a smoother and broader powerband.The new head has reduced squish area.
De-compression hole in cylinder head eliminated.
the 39mm Keihin FCR carburetor gets a double-lipped joint on the intake side so it is less likely to pop off a moveable fuel line joint to accommodate aftermarket tanks better and an additional fuel filter within.
New redesigned and beefed up clutch with 12 percent stiffer springs.
New clutch lever and perch were created to keep the lever pull nice and manageable.
New Renthal aluminum handlebars
New kickstands (Aluminum)
New Lighter, more durable steel rear sprockets.
New front and rear wheel collars
New rear brake carriers make removal and replacement of the wheels much easier during trailside flat repairs
New front brake lines. Since Honda's patent ran out two years ago, Yamaha was able to more directly route, and thus shorten, the front brake hose.
YZ's one piece lower guards.
New AIS system added.
New muffler.
New Revised frame.
New Revised mainshaft, 3rd gear.
New Relocated crancase breather.
New Longer head pipe.
05 models also had the fuel tank redesigned to allow the use of YZ radiator shrouds. All WR's up to '04 had fuel tanks and radiator shrouds unique to the WR.


2006 WR450F Changes
Last Year for Steel frame
New Digital enduro computer
New shift detent pawl assembly.
Revised CDI map.
Rubber bumper bottoming controll in the forks were replaced with hydraulic lock collars.
The cams were revised but the WR still shared the same intake cam as the YZ.


2007 WR450F changes;
First year for aluminum frame
New ovoid headlight
New2.1 gallon YZ-F-style fuel tank
New engine and balancer. New cases/head. Crank/trans 2mm wider. Cams, piston, clutch, kickstart shaft, shift detent assy, water pump cover. starter drive carried over from 2006.
New integrated oil tank location
New camshafts. Revised cam profiles (first year that both cams were unique to WR and not based on the YZ profiles) The new cams have less lift and duration than previous years.
New exhaust system
New aluminum frame
New body styling
New LED taillight
New quick-access airbox
New wave-style disc brake rotors
New ProTaper handlebars
New wider footpegs
New full-coverage skid plate
New radiator with bracing
New radiator louvers
New forged top triple and handlebar clamps. Forks were identical to '06 but triple clamps were new and 2mm wider.
New seat cushion designSealed O-ring chain
New CDI.
Primary ratio to 61:23.
New Piston cooling jet added.


2008 WR450F Changes;
NONE


2009 WR450F Changes
Graphics


2010 WR450F Changes
2010 Model Not Available in US
Revised Gripper Seat Cover


2011 WR450F Changes
None


2012 WR450F Changes
•New fuel injection system delivers quick throttle response and smooth power delivery at nearly all altitudes and
temperatures.
•Compact YZ250F-based chassis provides a lightweight feeling with plush suspension performance for the most demanding
rider.
•The new WR450F comes equipped with the latest generation KYB® SSS YZ-type fork and shock, dialed in for off-road use.
•New slim bodywork with updated headlight design gives the WR450F an aggressive, tough appearance.

  • YamaJet

Posted January 15, 2012 - 07:20 AM

#2

If there are no more revisions I'll ask to have this made into a sticky.

Thanks to all that helped

  • YamaJet

Posted January 21, 2012 - 06:41 AM

#3

I'd like to get this pinned. I have PM'ed the moderators but have not heard anything back. Probably busy with the new site.

  • W R

Posted January 21, 2012 - 06:47 AM

#4

Nice work YamaJet. This would have been great while I was researching before I bought my 2011. By the way have you got all of your mods done to yours yet?

  • 2grimjim

Posted January 21, 2012 - 09:06 AM

#5

This thread has some more details about what parts interchange.
http://www.thumperta...s-on-the-wr450/

Most people dont realize that a lot of performance parts for the YFZ (ATV) will work on the WR. Hot Cranks doesn't list a stroker crank for the WR but they do for the YFZ and it will work on the WR.

One interesting note about the difference between YZ, WR, and YFZ is the decompression pin on the exhaust cam. After some firsthand research with a degree wheel, dial indicator, and a pile of cams, I have some definative info on the differencees. those can be found here;
http://www.thumperta...ween-wr-and-yz/

Edited by 2grimjim, January 21, 2012 - 10:02 AM.


  • YamaJet

Posted January 22, 2012 - 05:59 AM

#6

This thread has some more details about what parts interchange.
http://www.thumperta...s-on-the-wr450/

Most people dont realize that a lot of performance parts for the YFZ (ATV) will work on the WR. Hot Cranks doesn't list a stroker crank for the WR but they do for the YFZ and it will work on the WR.

One interesting note about the difference between YZ, WR, and YFZ is the decompression pin on the exhaust cam. After some firsthand research with a degree wheel, dial indicator, and a pile of cams, I have some definative info on the differencees. those can be found here;
http://www.thumperta...ween-wr-and-yz/


A sticky with parts interchange is a great idea. Was aware that a lot of parts would interchange between YZ's and YFZ's since I have been wrenching on all types since 2003, but would have to research before I jumped into something.

  • 2grimjim

Posted January 22, 2012 - 09:44 AM

#7

I haven't played with the 400 or 426 in a while but if there's going to be a sticky, maybe some info on the changes on '98-'02 would be nice too.

Just off the top of my head, here were some of the changes;

1998
First year for the WR400. Identical to the YZ except for the following; WR spcific tank, seat, radiator shrouds, and rear fender; Addition of kickstand, headlight/tail light, heavier flywheel, lighting coil/voltage regulator, wide ratio transmission; Advanced exhaust cam, EPA compliant exhaust; Odometer and WR specific front hub.

The '98-'02 WR's can use same year YZ flywheel, stator, CDI, and trasmission. The later 426 head, crank, cylinder, and piston can be fitted to older machines. The 426 piston/crank used a 19mm wrist pin vs. a 18mm pin for the 400.

1999
Updates were made to the water pump shaft and seal to address leaking issues. Rear wheel redesigned and uses a different sprocket, bearings, hub, etc. Swingarm was redesigned to accomidate bigger axle.

2000
The lower triple clamp was lengthened (top to bottom) to increase clamping area and reduce twisting of the forks when the bars hit the ground. The YZ was increased to 426cc. Last year for stainless steel valves on WR's and YZ's

2001
WR recieved YZ displacement increase and Titanium valves. Changes to the clutch to improve reliability. Stopped painting the radiators black.

2002
No significant changes. Last year of the first generation engine design. Very few parts interchange with later gen II or gen III engines.


I have seen recent posts about using the 426 cylinder and a '03+ YZ/WR450 piston on the 400 bottom end. The 450's went back to an 18mm wrist pin and allows it to be fitted to the 400 crank. Since the 450 has the same bore size as the 426, the 450 will fit. I haven't verified that the compression height of the 450 is the same as the 426 however this swap has been done succesfully.

Edited by 2grimjim, January 22, 2012 - 03:45 PM.


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  • 2grimjim

Posted January 24, 2012 - 10:47 AM

#8

Parts interchange from Gen I-M ('98-'02 WR's and YZ's) to Gen II-M ('03-'06 WR's and YZ's) and Gen I-A YFZ ('04-'09).

Gear selector parts (segment, guide plate, stopper arm, ratchet lever) will interchange on all. Transmission output shaft is the same part number for all Gen I and Gen II 5 speed m/c (not YFZ).

All magneto parts will interchange on Gen I-M machines (stators matched with rotors), Gen I-M stators (YZ and WR) will bolt into all '01-'11 YZ250F cases. Gen I-M flywheels (all) may fit on '01-'11 YZ250F's with some modification.

Gen I-M cams will interchange with Gen II-M and Gen II-A but the base circle diameter is small and requires thicker shims. Timing marks are different and require a degree wheel to set up correctly.

  • Asondrup

Posted June 03, 2014 - 10:54 AM

#9

Can someone confirm this, Whole full suspension both front and rear fork from a 2003 WR450F will fit a 1998 WR400 ?

 

Please confirm :)

 

Many thanks



  • foggy3061

Posted June 04, 2014 - 09:25 AM

#10

Can someone confirm this, Whole full suspension both front and rear fork from a 2003 WR450F will fit a 1998 WR400 ?
 
Please confirm :)
 
Many thanks

I know the 46mm fork legs from a 2004 wr450f fits straight into a 2002 wr426f triple clamps. I would imagine a 2003 fork would fit a 1998 but you would need to mount it into the 1998's triple clamps.

  • TwoPotato

Posted June 06, 2014 - 10:40 AM

#11

How about bringing this up to date as of this posting...thanks much for the existing info also!!!  I am considering a new (to me) purchase and need the info...help



  • Asondrup

Posted February 01, 2015 - 02:06 PM

#12

Hi

 

I have this 03 WR450, and the crank is totally bust, and i am starting the rebuild just now, im going for the Wiseco bottom end rebuild kit, but cant seem to find any for the 2003 model, 2004-2006 is easy to find from almost every dealer around, my question is

what is to be done, to make a 04-06 Crank fit in my 03 WR450? New fly wheel? etc etc. ?

 

 

Thanks ! //



  • patrickwr

Posted February 23, 2015 - 04:22 PM

#13

NJ uI

  • toten

Posted February 23, 2015 - 06:35 PM

#14

My bike is an 03. I came across an 04 owner's manual. Are there any significant differences that I should be wary of?






 
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