2004 WR450F bringin' her back from the dead project

Hey tt ppl. I thought I may as well share my "little" project that I've got going on right now. With the long cold winter finally starting to release it's death grip on northern Alberta, I decided that I really wanted to get back into dirtbiking. So the search began for a fairly new, usually reliable dirtbike with functionning headlight/taillight that wouldn't leave me wishing for larger displacement after a month or two. I scoured the local online classifieds, looked at quite a few bikes but all the owners were asking too much for pre Y2K bikes which almost all were due for a engine overhaul. Then, an add caught my attention for a 2004 WR450f which according to the owner had a bad motor. So I called the owner, and he informed me that the motor was currently disassembled in boxes, and the "crank and piston are missing.".. I started looking at prices for new aftermarket cranks/piston combo's, and I decided that this bike was probably worth it to go take a look. So off I drove the 4hr drive (each way) to go take a look at the bike. When I showed up, the bike was partially disassembled, and as the owner mentioned, yep, the motor was in a box.. lol.. The plastics were cracked and beat up from obvious catwalks gone wrong attempts, but the frame appeared straight, the crankcase halves looked good, so I decided to lowball him a little, he met me in the middle for price so I was happy. So, I brought out my trusty socket/wrench set and finished the disassembly of the bike so I could fit the bike into the back of my Subaru WRX station wagon. Here's what she looked like after making it home :thumbsup:


Immediately after getting home, I power washed off the parts, and then carried all the parts into the basement to start the inspection/cleaning/assembly part of the project. Well, with the parts that I had, this is what either A: needed replacement or B: needed attention.

-Motor, well if you were to assemble all the parts that I got, it would look like a engine, except there really wouldn't be anything inside. It was missing every thru shaft, crank, piston, transmission gear, shift linkage, clutch, flywheel.... so.. yeah.. motor is done.. so I found a replacement 2006 WR450 engine in Texas with a spun bearing and it's in the mail now.

-Frame obviously got refinished to rid the rust and check all threaded holes. I had to completely remove both lower anchor nuts for the rear subframe because the threads were gone from the previous owner installing standard course bolts into a metric fine hole.. :thumbsup:

-Rear suspension linkage and swingarm bushings were 100% dry of grease and seized solid. All bolts/bushings had to be pressed out using a 20t press.. one bolt actually required almost 15,000 psi to break it free.. lol. While the others needed close to 8,000 psi each. So new bushing/bolts had to be ordered. Rear shock was in excellent shape (probably cause the rear links weren't moving) which was good a fairly pleasant surprise.

-Front suspension/Triple.. Upper triple needed replacing because again I found some standard bolts installed for the bar clamps. When I removed the steering head, some ball bearing fell on the floor so new bearing were needed. Fork seals were good, but the dust boots needed replacing.

-Controls.. hotstart/clutch perch and levers needed replacing, the only thing holding them together were the rubber boots.. roflmao. Throttle tube was cracked in multiple pieces. Throttle cable was pooched. Bars were bent. Front brake lever was broken under the boot (but master cylinder is good).

-Brakes.. front and rear brake pads were well past their expiry date... he must've been running using the backing plates on rotors for quite some time. So, new pads were in order, but surprisingly the rotors were in decent shape. Front and rear calipers/lines were in good shape after some cleaning and they showed no signs of wear.

-Body plastics.. everything was broken. period. But, the seat, tank and airbox were in decent/useable shape.

-Cooling. RH rad was bent and failed a leak check. LH rad was slightly bent, so I got some of our metal bashers to straighten it a little, and to my surprise it passed the leak test. Coolant lines also were in good shape, they're starting to get hard, but they're still useable for now until I get leak.

-Drive.. front sproket was missing teeth, rear steel sproket looked like a saw blade, and chain was garbage. Tires were off the bead but holding air. Once I removed the tires to inspect the rims, I found that both front and rear tire beads were done and both rear rim locks were damaged. I also had to true the rear wheel, I used a buddies truing rig to remove some lateral runnout which was out of spec.

Sooo.. as you can tell, the bike was a wreck. I found on ebay a rad from a 03 YZF, the motor I found on SMJ, all the plastics are coming from UFO plati, body hardware is coming from cheapcycleparts, and tires/tubes/chain/sprokets/exhaust I picked up while I was in Edmonton.

Here's how she sits right now



here's some of the parts unuseable parts along with the ever so growing pile of serviceable parts


and the motor.. :cheers:



Keep us posted....I am currently do a 2005 WR450F myself. It might need a motor soon, It does run very stong, But is pretty noisy.

But all in all my project bike is looking great, New plastic on,just gotta put on new rubber-got them today, Decal kit was shipped.

Just wondering what u paid for the motor....I'm thinking it'd be easier to got that was than a rebuild.

Good Post.

awesome man :thumbsup: i'm doing a 99 build up here in a bit and started going through stuff and found like you did with all the different size bolts, hopefully they didn't screw up the threads :thumbsup:

Looks like a fun project :thumbsup:

Be interesting to see when it's done.

I just finnished doing up a 03 RM250 this winter. Wasn't quite as bad a basket case, but it's like a new bike now :thumbsup:

well a little more work done today. Finished rebuilding both front and rear calipers with new seals and pads, mounted the new UFO chain slider and chain guide block, and mounted the tires on the bike just to see how tall the bike actually is... HOLY HECK she's a tall machine. I'm just under 5'7" and the seat is just above my belly button.. ROFLMAO.. when I sit on the bike I can get one foot kinda down to a tippy toe support.. the other is sky high. I'll have to figure out a way to lower the bike a little which will probably mean lowering the forks in via the tripples and possibly raising the rear spring perch to maybe bring the back end down a bit. I only need maybe .5" of lowering to be comfortable with the height. Then, if I feel like motarding it later on for street duty, it'll almost be perfect height using 17" wheels

But, another devellopment, seem the motor that's in the mail has... ummm... stopped moving. The person I bought the motor from packed up the motor into two boxes, supplied two tracking numbers. Both boxes arrived at the same time in Chicago, one box has cleared customs, the other is "arrived at International Dispatch ISC Chicago" and it hasn't moved since.. I think I'm gonna have to call USPS tomorrow to find out what's going on. Last time something like this happened, one of the employees decided to help themselves to the item I ordered in shipping and is now facing theft charges.

Also I ordered a new skid plate, and a front light assembly. Also, I finally found a graphic kit that works with my theme for the bike. I wanted a graphic that could have been supplied from factory, but on second look you realize that it isn't factory. It'll be custom made by bikegraphix but it'll look similar to this but with a few changes :


Looks like street rubber.....which explains the K&N.

Wow, that's a good "little" project you have there.

Looks like street rubber.....which explains the K&N.

Ooops....just realised it was a 'sample' photo. :thumbsup:

Good on you for taking on the project. However, I hope the price was free 99 or else.............

Been there done that and learned or in my case, didn't learn the hard way.........

tagging along, I just picked up a 04 WR450F with a blown crank/cylinder, the bike locked up last weekend, cylinder already off so I know i've gotta do one bent valve, and a new cylinder/piston and a new rod or whole crank depends on the cam gear

tagging along, I just picked up a 04 WR450F with a blown crank/cylinder, the bike locked up last weekend, cylinder already off so I know i've gotta do one bent valve, and a new cylinder/piston and a new rod or whole crank depends on the cam gear

Do you have a machine shop willing to do the rod? I believe the rod/crankpin/lower rod bearing are on backorder thru Yamaha.. but things might have changed.

if the cam chain teeth are ok I'll have mrcrankshaft do it, if not I'll put in a wiseco, I budgeted for a whole new crank,

rebuild crank 129 $

new wiseco 225 $ includes main bearings

cylinder works big bore kit with piston/gaskets 478cc 395 $

honestly I'll probably just do wiseco, I think they are US made again, the rebuild + mains is almost as much as the wiseco, and then I know the cam chains gear is good

Here's the project bike I just got, it was taken care of right up until it blew up, everything has come apart easily, even the swingarm was greased

I have no idea what you have to do to this to get a piston to lock up like this, it wrecked the rod and cylinder

all 3 intake valves touched the piston, I'm not sure if i wanna try doing the head myself yet, I usually have someone else do it





HOLY HELL !!!! that's some serious damage going on there.. WOW..

I would hazzard a guess that probably it was wrist pin bearing which seized, which then started putting excess strain on the piston side skirts.. which then work hardened it until it broke.. which then took out both the cylinder and the head... HOLY FAUK... wow.. just wow. Other than that, the bike looks really good.. doesn't even look like it's been riden at all.

Well here's some updates for mine.. it was like Christmas for me today. Received the rest of my order from UFO, and the radiator I won on ebay, and also 3/4 the engine came in the mail.. which is awesome because it'll provide something for me to do over the Easter long weekend.. disassemble, inspect, and order the replacement parts for the engine :thumbsup: But, I did manage to get the body fit testing done already, and I have to admit, I really like this UFO LED taillight assembly.. especially because UFO managed to order me in the version for my bike in White...

Here's some pictures... I'm starting to get excited, finally the bike is starting to look like a bike and not some random pile of parts on my basement floor. The "motor" in the chassis is the cases which came with the bike, and the motor on the floor is what I picked up in Texas :thumbsup:





But on a side note.. I think I've gotta try to find a kickstand for this machine.. I'm not really diggin the motoX axle stand.. the bike doesn't feel secure resting on it

the intake cam journel is pretty bad, the buckets would not come out until I removed a metal lip that was forming at the cam

all 3 intake valves hit the piston, 1 is bent badly, the other 2 probably are but I cant see it visibly

I've heard of getting the cam journals welded and machined, now idea how much it costs, I am not sure if I will repair this engine or part it out, this place does it, http://enginedynamics.com/index.html

I'm gonna have a spare head/cylinder once the rest of the engine in shipment arrive... that way you don't have to part her out, you can fix it :thumbsup:

The head pictured is a 04, and the head in the mail is a 06. I'll probably only be using the 06 stuff on the bike. On my 04 head, all the valves are removed, the seals look good, valve journals are good, and all 5 valves look like their straight. But the camshaft bearings are slightly notchy feeling (ie.. worn beyond limits). Also the 04 cylinder looks great, not a scratch on it, cross hatch is still visible.

I won't be able to officially sell anything off the motor right now until I receive all the rest of the parts in the mail to inspect them in depth. But, if you're interested, lmk.

I've been reading that the intake cam journals is a problem with the yamaha's, too tight of machining

waiting on a reply from enginedynamics, i've heard they can fix mine for 129 $ then all I would need is 3 new valves

easy enough let me know. I'd send them all the pictures you posted of the head. I'm not sure if they'd be able to fix the piston hit on the valve face (between the cyl & cam chain hole).

the nick from the piston looks worse than it is, not something I'm worried about once cleaned up

I'm going to polish the cam journals and measure clearance before I do anything, yamaha runs tight, .001-.0015, most other brands run .003-004, the cam journal problem is common

I'm gonna split the cases too, I dont like to order any parts until I have a complete list of what's needed

all 3 of my intake valves are bent

I'm leaning towards parting out the bike, the head damage pushes it into the too much to fix realm, good running bikes sell for 2k here

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