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Just_a_trail_rider

05 wr450 rebuild pics after 5 years (lots of pictures)

59 posts in this topic

Here is what the piston and valves look like after 5 years, a shit load of miles, dual sport rides, LAB2V twice and loaning the bike out many times. I do remember that I broke my trailtech a year and a half ago with over 4500 miles logged. My estimate is that it has about 6K miles. I shimmed one valve about 4 years ago. No adjustments since. Its still got good power to haul my fat ass around, but doesn't power wheelie in third like it used to (which scares the crap out of me anyways)

Looks like I was burning a little oil. Well... Maybe more than a little. Still has good power though. Notice that rusted spark plug. Its seen a few water holes, that's for sure.

Cylinder looks good. Piston looks pretty good too. I noticed a small amount of metal shavings on the flywheel, but I've never had that cover off in 5 years. Who knows what that is and how long its been there. I probably could have ridden this thing for a while longer, but I had to get that spark plug out and removing the head was the only way.

I now know for an absolute fact that 2 strokes are easier to work on. :thumbsup: There's no doubt about that whatsoever.

Total top end parts is cheap though. I've spent only $300 so far, but I won't take any shortcuts on this rebuild. It’s the smashed up stuff I have to replace that is going to be expensive.

450-topend-01.jpg

450-topend-03.jpg

450-topend-02.jpg

450-topend-04.jpg

Click the arrow for part 2 and more pictures
Click the arrow for part 3 and more pictures
Click the arrow for part 4 and more pictures
Edited by mauricedorris

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Good to see! keep us posted, I'm about to pull down my 99 wr400 for the first time.

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Thanks for the pics. I don't have anywhere near the miles you do but it's good to see what awaits me.

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So basically after 5 years of mucho riding the only thing it needed were rings? Thats not bad. :thumbsup:

So what are your plans? High compression piston perhaps? You mentioned "smashed up" stuff, can you explain what was "smashed up"

I've seen the same thing on a blue 250f. The damn thing had been thrashed since '04 and the only thing it need in the top end was rings and a timing chain. The only reason it was apart was because the gear on the water pump shaft exploded and cracked the right side case.

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At a bit more than 7000 miles, my 426 came down. The top end was still in really good shape. The primary drive nut tabbed washer wasn't bent up properly, and the nut backed off. The splines on the crank were all dorked up...but the stock piston could have gone back in...and the original valves could have gone back in...

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So basically after 5 years of mucho riding the only thing it needed were rings? Thats not bad. :thumbsup:

So what are your plans? High compression piston perhaps? You mentioned "smashed up" stuff, can you explain what was "smashed up"

I've seen the same thing on a blue 250f. The damn thing had been thrashed since '04 and the only thing it need in the top end was rings and a timing chain. The only reason it was apart was because the gear on the water pump shaft exploded and cracked the right side case.

So is that 250f back in one piece and running? It's been a while since that thing broke down @ hollister.

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So basically after 5 years of mucho riding the only thing it needed were rings? Thats not bad. :thumbsup:

So what are your plans? High compression piston perhaps? You mentioned "smashed up" stuff, can you explain what was "smashed up"

I've seen the same thing on a blue 250f. The damn thing had been thrashed since '04 and the only thing it need in the top end was rings and a timing chain. The only reason it was apart was because the gear on the water pump shaft exploded and cracked the right side case.

I know that the bike was way down on power from riding other wr450's. But unless you rode others back to back, you'd never know. I probably never use more than half the throttle anyways. It pulled me up some pretty gnarly hills with just a little more twist of the throttle. I like the slower technical trails.

this was my first dirt bike, so it goes without saying that it scared the crap out of me with the power it had. I've always had more ambition than talent, so my frequent attempts at difficult terrain would lead to painful get off's and broken bones :lol: But riding/racing my yz250 smoker has quickly (and painfully) taught me better throttle control, so I think I can handle a 450 with full power, even if its just the wr.

The main reason I took it apart is because I couldn't get the spark plug out. You can see how rusted it was. If it weren't for that, I'd be riding it still.

The plans are for a stock piston and setup. I considered a set of cams, but this is not the race bike anymore. This is my summertime dual sport ride that I normally take up to higher elevations in the summer. I don't want to have to rely on race fuel. Besides, I'm a half throttle kind of guy who's loves the 1st and 2nd gear technical stuff.

But looking at the piston and how much oil I was burning, I can definitely say now that I will not let it go this long again. I'll replace the rings more frequently now that I am familiar with removing the top end.

Regarding the smashed up stuff... The bike show lots of wear and tear. both foot pegs are bent, the brake lever is bent, there's a small crack in the clutch cover, the frame guards are twisted, the bash plate looks like hell... that type of stuff....

Edited by mauricedorris

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so... someone suggested that I send the head and valves to a shop to get it tested and inspected for peace of mind.

My mind was already somewhat at peace because I took apart a bike that was running with no problems (except it burned a little oil)

So I did what I call the "poor man's leak down test"

I took the cylinder and turned it up on its side, then I filled up the intake chamber with gasoline to see how much would leak past the valves. As expected, it didn't loose a drop.

I did the same thing with the exhaust side. Not a drop.

Suffice it to say, I'm putting this head and these valves back on the bike.

Pics below.

450-topend-05.jpg

450-topend-06.jpg

Edited by mauricedorris

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so... someone suggested that I send the head and valves to a shop to get it tested and inspected for peace of mind.

My mind was already somewhat at peace because I took apart a bike that was running with no problems (except it burned a little oil)

So I did what I call the "poor man's leak down test"

I took the cylinder and turned it up on its side, then I filled up the intake chamber with gasoline to see how much would leak past the valves. As expected, it didn't loose a drop.

I did the same thing with the exhaust side. Not a drop.

Suffice it to say, I'm putting this head and these valves back on the bike.

Pics below.

450-topend-5.jpg

450-topend-6.jpg

Same way I tested mine when I rebuilt my top end only I use brake cleaner rather than gas.

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Same way I tested mine when I rebuilt my top end only I use brake cleaner rather than gas.

Good to know the old school techniques are still being practiced. I used to do that with my old toyota 25 years ago to check the valves.

Whats the best way to clean all the carbon and stuff off of the head? Or does it really matter?

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Good to know the old school techniques are still being practiced. I used to do that with my old toyota 25 years ago to check the valves.

Whats the best way to clean all the carbon and stuff off of the head? Or does it really matter?

Scotchbrite and solvent. If it's really hard to get off you can use some oven cleaner.

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The main reason I took it apart is because I couldn't get the spark plug out. You can see how rusted it was. If it weren't for that, I'd be riding it still.

I see. Besides swapping plugs out every year what could prevent that? I was thinking anti seize but that might mess with the spark. Could dielectric grease prevent that. Steel bolts (spark plug) into aluminum threads can result in nasty things :)

The plans are for a stock piston and setup. I considered a set of cams' date=' but this is not the race bike anymore. This is my summertime dual sport ride that I normally take up to higher elevations in the summer. I don't want to have to rely on race fuel. Besides, I'm a half throttle kind of guy who's loves the 1st and 2nd gear technical stuff. [/quote']

:thumbsup:

Wet or dry rebuild? Hard or easy break in? :lol:

So is that 250f back in one piece and running? It's been a while since that thing broke down @ hollister.

We are shootin' for later this month.

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We are shootin' for later this month.

So are you getting your hands dirty with that motor rebuild? Or are you just giving him verbal instructions?

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So are you getting your hands dirty with that motor rebuild? Or are you just giving him verbal instructions?

I meant we're planning for a ride later this month.

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If I were you I would make sure to replace the exhaust gasket in the head as it is a crush style and one time use. And also the timing chain which you probably already are...

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I meant we're planning for a ride later this month.

oh, nice. I haven't been to hollister since that day his bike broke down, maybe just once after that. The rain in the last few weeks has been making me want to ride @ hollister.

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OK... here's more photo's. I'm sure that all of this is very familiar to you experts, but its new to me... so I'm sharing.

What's really interesting is trying to photo-document the process. Props to you guys who always to that.

Here are the photo's:

Here's a repost of the poor man's leak down test pics

450-topend-05.jpg

450-topend-06.jpg

Here is the removal of the flywheel nut. Its an 18mm. I've learned my lesson about using 12 point sockets. They can strip. I only use 6pt sockets now.

Notice the "poor man's" engine lockup tool, which is a small piece of wood wrapped in plastic cause it was dirty. What you can't see is that there is another small piece on the front side of piston. This works perfectly.

450-topend-07.jpg

Here's the removal of the flywheel using my ebay flywheel puller and the same 18mm socket and a crescent wrench. Be sure to get the correct puller. There are different ones to get based on which year bike you have. Notice how I used the foot peg for leverage. I had to put a little muscle behind the socket and it gave out a loud snap before the flywheel slid off.

450-topend-08.jpg

Remove the flywheel and the gear behind it and you can see the cam chain and the rear cam chain guide. They are both easy to remove.

IMPORTANT: There is a little "dowel pin" (if that's what its called) that goes between the flywheel and the crank shaft. It aligns the flywheel to the correct position on the shaft. I didn't know it came off until it fell on the ground when I removed the flywheel. Its very small, so look for it. Its going to be needed for reassembly.

(edit: that "dowel pin" is actually the woodruff key. It aligns the flywheel to the correct position on the crank. Its very important)

450-topend-09.jpg

Notice the old and new cam chains. The new one is on the bottom next to the screw driver. They are the same lenght and it hasn't been stretched or anything. Oh well... I'm going to replace it anyways. I already got the new one.

450-topend-10.jpg

New cam chain installed. I had to remove the bolts from the chain guide. I put a little blue locktite on the bolts before putting them back in.

450-topend-11.jpg

Here's the removal of the clip on the piston. Why doesn't 2 strokes use snap ring clips like this? It was too easy!

450-topend-12.jpg

Here's the removal of the piston pin. I gave it a slight push from the other side before pulling it out.

450-topend-13.jpg

Here is what the skirt on that piston looks like after over 6,000 miles. Not too bad. It wears nicely. I'm replacing the piston because I already got the kit. But next time, I'll pull the piston and check it out first. I think I could have easily cleaned up and reused this and saved the $100.

450-topend-14.jpg

Now its time to clean the old gasket off the case to start the reassembly

450-topend-15.jpg

More pics later when I do more...

Click here for part 3 and more pictures
Edited by mauricedorris

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Mo, thanks for the pics. I don't plan on having to do my 450 for awhile, but this will be good info. BTW, the small dowel pin is a woodruff key. I'm glad to see the WR can take the abuse you've given it and still be in good shape.

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Mo, thanks for the pics. I don't plan on having to do my 450 for awhile, but this will be good info. BTW, the small dowel pin is a woodruff key. I'm glad to see the WR can take the abuse you've given it and still be in good shape.

Oh... so that's what its called. Nonetheless, I'll remember to put it back in.

Regarding the abuse... I was feeling bad looking at my bike from the outside. It would appear that I don't like the bike, when I fact I do. But obviously, the insides are still pretty good.

Based on what I see here and how few miles you've got, you should schedule your top end somewhere around 2014.

Edited by mauricedorris

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