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


58 replies to this topic
  • shrubitup

Posted April 07, 2010 - 08:03 AM

#21

Maurice, what's with the garbage bag attached to the front of the frame in one 'dem photos?

Snap rings, what an invention! I still manage to do OK with circlips but the snap ring looks mo' better fo sho.

Make DAMN sure the woodruff key seats to the crank and flywheel. I did a poor job of that once and had the FW spinning which ultimately broke my kick start linkage on the smoker (in addition to the side case).

  • Just_a_trail_rider

Posted April 07, 2010 - 08:42 AM

#22

Maurice, what's with the garbage bag attached to the front of the frame in one 'dem photos?

Snap rings, what an invention! I still manage to do OK with circlips but the snap ring looks mo' better fo sho.

Make DAMN sure the woodruff key seats to the crank and flywheel. I did a poor job of that once and had the FW spinning which ultimately broke my kick start linkage on the smoker (in addition to the side case).


The garbage bag holds my lunch from a couple of days ago :thumbsup:

Just kidding... inside of that bag is the stator. I didn't want it just flopping around.

Thanks for the woodruff key warning. I'll make sure I get it back on there.

I suppose I'll have to use a little pressure to get the flywheel back on, right? Maybe lightly tapping it with something?

  • SoCA_DRZ

Posted April 07, 2010 - 08:57 AM

#23

Make DAMN sure the woodruff key seats to the crank and flywheel. I did a poor job of that once and had the FW spinning which ultimately broke my kick start linkage on the smoker (in addition to the side case).


I second that. The first time I replaced the crank in my 01 YZ 250, I forgot to remove the woodruff key from the old crank and install it on the new crank. By shear dumb luck, I had the timing close enough where the bike would still start, but run like crap. I couldn't figure it out and ended up taking it to a mechanic. One of the first things he went to check was timing and called me about an hour later and told me there was no woodruff key! D'oh, I felt like an idiot! Luckily, it was one of the first things he checked, so he only charged me 1/2 hour of labor. He installed a key that he had in his shop and the bike fired up and ran great!

  • Butta

Posted April 07, 2010 - 07:22 PM

#24

I'm all about saving money, which is why I'm going to suggest that no matter what the piston looks like, after that many miles (which is far from being scared of a blow up...) if you're in the motor anyway, REPLACE whatever you can that is a known wear part. Save the $100 by reusing the piston and it could cost you 15x that (or more)...

  • gscx

Posted April 07, 2010 - 07:40 PM

#25

One thing i see that could cause problems is using the wood to hold the piston up, i did that once and it broke a piston skirt on my yz. After that i just stuffed a rag in the crankcase to keep in from going all the way down

  • Just_a_trail_rider

Posted April 07, 2010 - 10:24 PM

#26

One thing i see that could cause problems is using the wood to hold the piston up, i did that once and it broke a piston skirt on my yz. After that i just stuffed a rag in the crankcase to keep in from going all the way down


Yep... I did notice the the front of the piston was wedged against the case. There are three wood shims beneath that rag that are between the skirt and the case. But your warnings are a absolutely correct. The rear of the piston just digs into the wood, which is no problem.

I'm all about saving money, which is why I'm going to suggest that no matter what the piston looks like, after that many miles (which is far from being scared of a blow up...) if you're in the motor anyway, REPLACE whatever you can that is a known wear part. Save the $100 by reusing the piston and it could cost you 15x that (or more)...


If the beginning of the thread, I mentioned that I already have a new piston. It will get replaced. However, I don't want to replace things "just because". If I took that approach, then I would get all new valves and valve springs. I'd replace some of the gears that I am pulling off. Oh and since the motor is already torn down, I might as well pull the bottom end and replace the crank and bearings. That would then lead me to just going to the dealership and getting a whole new bike... just to be sure of course. My $300 top end would turn into a $6500 new bike.

All kidding aside, I think its ok to replace just what's worn and not replace parts that are still "in spec". That $100 I spent on the piston could easily pay for other parts that are truly needed.

The important thing going forward would be to not wait 5 more years before I tear down and inspect the engine. Although its a little more tedius and will take a few hours more than working on my 2 stroke, it isn't hard at all. I could do it all again in two hours tops.

  • spick

Posted April 08, 2010 - 08:59 AM

#27

I have over 7,000 km on my 06 now. I'm guessing I should dig in and do this at the end of this season.

I'm slowly getting to know my bike, and wished I had spent more time on regular maintenance. I've changed the oil plenty but other than that, not a heck of a lot. Last season I pulled and regreased the steering stem. And I've just pulled the swing arm and replaced the lower linkage bearing and cleaned and regreased the rest.

This will be a whole other task but my shed will be in better shape at the end of this season with power, lights and heat, allowing me to work over the winter and take my time with it.

Thanks for the pics. They will inspire me when the time comes.

  • Just_a_trail_rider

Posted April 08, 2010 - 11:57 PM

#28

OK... I got a little bit more done today. If I didn't have to work, I might be able to do more than about an hour at a time.

Today, I put the new piston on and installed the cylinder and head. Here are some more pics and things I learned along the way.

Here's the new prox piston kit that I bought from RockyMountain ATV. It wasn't that expensive.
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According to the manual (which I am reading for a change), you have to align the ring gaps at certain places on the piston. I marked it so I would remember

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Here is the piston installed onto the rod

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My cylinder was in great condition and it only needed a little cleaning up with a scrotchbrite pad, which I did. Here is the cylinder going over the piston and rings. Notice that I could not resist using the circlips on the piston again. The local dealer happened to have some in stock. Parts at the dealer... imagine that!

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After checking the up and down movement of the piston in the cylNow I placed the head on top of the cylinder. While I was at it, I also replaced the hoses with some fancy red ones I got off of ebay. (Note to self... check the hoses frequently)
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Now I need to bolt the head on. There is a particular procedure that I found in the book. I thought it would be a simple torque spec. But it says to do the following:

1. lube the head bolts and washer and torque them down to 30 ft/lbs
2. remove the head bolts and lube them again
3. reinstall the head bolts at 14 lbs
4. mark a spot on each bolt using a marker
5. tighten the bolt an additional 180 degrees using the mark as a guide
(it goes without saying to use a proper criss/cross, incrimental torquing procedure)

Here is me lubing the bolts

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then I torque them down to 30lbs, remove them, lube again, then torque to 14lbs

Posted Imagelbs.

Here is the initial mark I put on the bolts after torquing them to 14lbs.

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Here are the bolts after rotating them 180 degrees.

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It feels pretty good to simply follow the book. Its easy at this point.


Will do more tomorrow when I get some time..

(Next steps... replace the ignition cover and everything behind it. Install and align the cams)

  • spick

Posted April 09, 2010 - 04:53 AM

#29

It will be interesting to note if you feel any performance gains once you complete this process. Looking forward to it.

  • Just_a_trail_rider

Posted April 09, 2010 - 06:33 AM

#30

It will be interesting to note if you feel any performance gains once you complete this process. Looking forward to it.


The power was noticeably down already compared to other WR's. I've even had others comment on it. But it wasn't an issue at the slow speeds I normally ride at. ( 80 miles / 4 hrs)

I went completely stock with the piston and am using the stock cams. So I hope to have the strong, highly manageable, but kick-ass performance that makes the WR so damn popular. It would also be nice to loft the front wheel easier to get over logs and rocks in the mountains. Right now it doesn't come up that easy.

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  • shrubitup

Posted April 09, 2010 - 07:05 AM

#31

Thread subscribed to. :thumbsup:

  • floatingk

Posted April 09, 2010 - 11:53 AM

#32

I just did the same thing to my 04 yz450. I bought it from a guy who raced the living piss out of it, and then I rode it in the woods like you do. I figured it could go for some piston ring love so I tore the top off and put new rings in and left all the other old stuff on there bc it was so good (machinist said the cylinder was exactly factory spec) and still had the factory cross hatching (nikasil is bad ass). Adjusted two valves and it now tears like a bat out of hell. Kinda scary really.
Love the post, keep it up.

  • Just_a_trail_rider

Posted April 13, 2010 - 07:35 PM

#33

OK... lets get back to it. Last I left off, I had torqued the head bolts according to the instructions in the manual. Now lets get the cams and ignition cover back on.

Here is where we stand right now.
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I put the starter clutch drive gear onto the crankshaft. I did remember to put the woodruff key back on the crankshaft also.

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Now the flywheel goes back on.
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Now I need to do some old school tricks to torque the flywheel bolt on. I had to break out my "government issue" engine lockup tool. Its not expensive. It normally cost only a penny, but its actually $2.01 in Obama dollars! (yeah... I said it!)

Just put this between the gears and you can torque the flywheel bolt to 47lbs per the manual. What's not pictured is me using my impact wrench to remove it again, and then tightening it a second time. That's what the book says to do... so I did it.

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Now lets put the stator and ignition cover back on. We are going to need those timing marks

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the torque limiter and cover goes on next

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OK... now lets get those cams installed and lined up correctly. I did it per the book. I lined up the timing mark at the bottom first, then I positioned the cams so that 1) the lobes where pointing towards the front for the exhaust and towards the rear for the intake. Then I could see the timing marks on the cam sprocket. I made sure that the two marks were lined up with the top of the head like you see here.

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But before I bolt on the camshaft caps, I want to see exactly what shims I have. So I'll remove and measure each shim for each valve. It doesn't hurt to know these things.
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The shims had some faded numbers on them, but I measured them anyways to verify. Once I figured out how to properly use the micrometer, I measured the following.

Left side exhaust: shim #189; micrometer = .075 inches or 1.90mm
Right side exhaust: shim #189; micrometer = .075 inches or 1.90mm
Left side intake: shim #184; micrometer = .072 inches or 1.83mm
Middle intake: shim #192; micrometer = .076 inches or 1.92mm
Right side intake: shim #188; micrometer = .074 inches or 1.87mm


This is good stuff to know, at least it is for me personally.



Now put the cam caps on and check those valve clearances. I checked the clearances by gently pushing the feeler guage between the cam lobe and the shim bucket. Don't force it or it will give you a false reading.

IMPORTANT: You must rotate the crank at least three or 4 full cycles (8 revolutions) so that the shims and the valves settle into their correct place. I didn't do that and had some really crazy measurements that initially had me thinking I did something wrong. This was in the book. So I did it and then measured.

Posted Image

My results were what I expected them to be.

Left side exhaust: .203 clearance
Right side exhaust: .203 clearance
Left side intake: .102 clearance
Middle intake: .102 clearance
Right side intake: .102 clearance

All within spec as they have been for the past few years. Its all at the minimum level, but I hear that Yamaha likes it that way. There's probably a couple of Honda guys right now blowing up the suicide prevention lines because of their valve problems.

I think that's about it for the top end work.


I'll put it all back together now and see if I can get it to fire up.

stand by for results

  • latitude777

Posted January 30, 2011 - 08:09 PM

#34

Im keen to find out how it all turned out!

Just about to start the rebuild of mine, siezed the head when my headgasket blew last year and its been sitting ever since. Only im planning on doing a crank replacement at the same time.

Good work and thanks for the photos, always good to see/know what you can expect.

  • OUTERLIMITS

Posted January 31, 2011 - 05:55 PM

#35

This thread just reminded me why my next bike will also be a Yamaha :thumbsup:

  • MANIAC998

Posted February 01, 2011 - 06:37 AM

#36

Excellent writeup! If your going to be running those valves on the minimum side of the spec, I'd make sure you keep a watchful eye on the clearances. I've never seen them get more clearance, only tighter. And it doesn't take much to burn them up either. I'd write down the shim sizes, and there location in the manual. That way, when it does become time to re-shim, you'll already know what size shim you'll need to order and where to place it. Keep up the great work, and let us know how it runs!!! Maniac

  • GuyGraham

Posted February 01, 2011 - 11:02 AM

#37

Posted Image

Once I figured out how to properly use the micrometer, I measured the following.


Er... thats a vernier caliper and a plastic one at that

They are known as 'Very Nears' coz the size it tells you is only very near the true size
A good quality (Mitutoyo or similar) will have a +/-0.001" reading error tolerance - don't like to think what a plastic one has

Get yourself a proper mic and measure them again

  • Flooder305

Posted February 01, 2011 - 02:06 PM

#38

Posted Image



Er... thats a vernier caliper and a plastic one at that

They are known as 'Very Nears' coz the size it tells you is only very near the true size
A good quality (Mitutoyo or similar) will have a +/-0.001" reading error tolerance - don't like to think what a plastic one has

Get yourself a proper mic and measure them again


That was posted back in April of 2010.... While I agree with your post, methinks that ship may have sailed.... :thumbsup:

....and seriously, whatever happened with this thing, what a great thread without a proper ending....

  • MotoChris521

Posted February 02, 2011 - 11:51 AM

#39

I guess it didn't run ?

  • Reedus

Posted February 04, 2011 - 06:49 AM

#40

I
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.


Spark plug is easy to access without taking head off or even valve cover. You need a 3/8 ratchet, shorty extension, spark plug socket, and telescoping magnet. Drop the socket in the hole, then attach the shorty extension, then the ratchet. After you have turned it out, in order to remove it, take off the ratchet, then pull up the extension and remove it from the socket allowing the socket to fall back in the hole. Then fetch the socket and spark plug out with your magnet. Easy Peasy, yams are a breezy.




 
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