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Valve Adjustment


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I keep reading about riders adjusting the valves on the YZ400 and WR426. Can anybody briefly explain what you need to do? Is this a problem with the Yamaha or just the nature of the beast? Thanks, Dennis

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Dennis,

There is a good description of this procedure on the tech side of Thumpertalk. Click here.

Unlike XRs, KTMs etc. the Yamaha has two cams and no rockers. So the cam to valve clearance does not have a rocker arm in the equation because the cam rides (more or less) directly on the valves. So the only way to adjust this clearance is by removing the cams, the valve “buckets” have shims under them to fine tune the cam/valve clearance.

As the valve seats wear this clearance diminishes, at some point most YZF/WR owners will have to swap the stock shims for thinner ones to bring the clearance back into spec.

Don’t worry, it isn’t that hard and it takes a while for most bikes to go out of spec.

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I would just add one small piece of advice. PATIENCE! Take your time and be very methodical. Expect to spend at least 4 hours the first time. It gets much easier after that.

Hick: I went to that site and read over those instructions so I cam back and have another piece of advice to make this procedure a bit easier. After doing my valves the first time and struggling with getting the cams reinstalled and timed properly, I came up with this idea that made the second time around go so much quicker and easier. Once I had the piston at TDC and the cams facing opposite of each other, I used my Dremel tool with an engraving bit and made a small mark on the side of the cam chain directly above the dots on the cam sprockets(both cams). This way, when I was reinstalling the cams, all I had to do was visually align the dots with these makrs and I knew that the cams were properly timed the FIRST time. I didn't have to go the route of installing..checking the crankshaft marks....moving the cam(s) over one tooth and rechecking...etc. I was finished in about 45 minutes compared to nearly 5 hours the first time. Of course, this only works as long as the cam chain isn't allowed to move over any teeth at the crankshaft sprocket. Other than that, the description is spot on.

[This message has been edited by Boit (edited 12-27-2000).]

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this is how you do it if you want to goto Thumpertalk.com then click HERE this is how i did that

substitute the <> signs in instead of the []...i had to do this so i could show you the html code! If you want to learn more on html look at the code for this page (by using the 'view source' on you browser IE or netscape)

[a href=https://www.thumpertalk.com]HERE[/a]"

Hope this helps and i didnt cofuse you too much! ?

Garrett

------------------

I get my kicks on a 2001' YZ426!

Friendswood, TX

[This message has been edited by motoman393 (edited 12-28-2000).]

[This message has been edited by motoman393 (edited 12-28-2000).]

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Thanks Garret, when are you coming to Bayou MX ? I rode last sat and tuesday and had a blast. I just got my boy a KX 65, and he's been eating it up out there.

I hope I can figure this link sh.. out, I'm trying to learn html and make my first web site, if you know some good info out there for me for beginers let me know.

Thanks, Jason

Beaumont, TX

Where can I get a book on html ?

[This message has been edited by jaybird67k (edited 12-28-2000).]

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Jason,

You could try the “HTML for Dummies,” its not bad.

But I think an equally effective way to write your own page is a hefty dose of cut and paste plagiarism. Look on your browser menu for a “view source” command. This should open up Notepad, a text editor, with the html code of the site displayed on your browser.

Then you can edit the text, copy and paste the commands and learn how the commands work. To see your changes, just save the text file in Notepad on your hard drive using the *.htm extension. Now open this file with your web browser.

Cutting and pasting and viewing your changes off your own hardrive is a good hands-on way to figure this stuff out. Whenever you’re just surfing around and see a feature you don’t know how to code, just view the source and you can then duplicate this by cutting and pasting the appropriate parts to your page. It is much simpler than you probably realize.

But try to avoid frames and tables at first. These aren’t complicated features by any means, just more involved (and cluttered).

As for posting links and pics here on Thumpertalk that isn’t necessarily the same, the UBB software interprets text differently.

IMG SRC=https://www.thumpertalk.com/ubb/thumper01.jpg A picture displayed in HTML

IMG]http://www.ach2m.com/moto/burt03.jpg[/img UBB version

The only thing missing is the outermost brakets, I had to leave those off to allow the actual text to be displayed (HTML uses <>, UBB []).

I always use the UBB method but both should work in posts here since the reply/post page indicates HTML & UBB are both “on.”

I think. ?

Hope that was some helpful OT info…

[This message has been edited by Hick (edited 12-28-2000).]

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That is some very helpfull imformation Hick, and I sure do appreciate it. Have you ever used Microsoft Front Page ? I have it and the guy that built my computer said it is a great program for creating websites.

I have also found a great link for beginners on html. Click here

Thanks, Jason

I hope my link works.

IT WORKED ! WHO'S YA DADDY

Damn.....you guy's rule !

[This message has been edited by jaybird67k (edited 12-28-2000).]

[This message has been edited by jaybird67k (edited 12-28-2000).]

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Jason,

I will go to bayou whenever i get the "ole man" to drive out there, he thinks the track is going to be too hard (like every other track we goto) and he thinks he will get roosted my little kids like your son on his new KX65...congratulations you have just introduced your son to dirtbikes it will be in his blood forever (i know it is in mine) ! I will try to get there fairly soon! We ride at highlands, 290 , rio, and mills road all the time (1 or 2 times a week) maybe you could meet us or the other way around...i have an html book that i used to get started it is called "creating web pages with html simplified", i got it at bookstop for around 15 bucks! Goto my site http://www.gmb-computers.com and look at the page source it is fairly basic html! Since im only 15yrs old I have to find a way to afford to ride dirtbikes so i build computers/websites/LAN's for people (that why its called GMB-computers) and that is my own business i guess! There is some pics of me/friends/family and my dirtbikes on there so check it out! Hope this helps!

Garrett

------------------

I get my kicks on a 2001' YZ426!

Friendswood, TX

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Garret,

Bayou MX is a very hard track if its not fresh tilled, it gets hard as glass.........scary hard !!!

Do they have websites for mills,rio,&290 ?

I would like to get directions to those tracks and times that there open.

E-mail me & I'll give you my phone #, maybe

you or your dad can give me directions to these tracks.

Later, Jason

I also play MX madness 2

[This message has been edited by jaybird67k (edited 12-29-2000).]

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I am preparing to check the clearances on my valves in the next 1-2 weeks on my 426...I am wondering if you guys have any "tricks of the trade" or things that would make it easier (or quicker)! I read the manual and some articles many many times (it looks fairly easy :eek ?! Boit... I read your post about using a dremel to make a line on the cam chain to be sure the cams are aligned (sounds like a great idea)! Yamaha sure made it a hassle to adjust the valves (my XR400 was easy to adjust... took 20 mins)! Anyway if yall have any comments or hints on how to make my life easier i would appreciate it! Thanks,

Garrett

------------------

I get my kicks on a 2001' YZ426!

Friendswood, TX

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Originally posted by jaybird67k:

Thanks Garret, when are you coming to Bayou MX ? I rode last sat and tuesday and had a blast. I just got my boy a KX 65, and he's been eating it up out there.

I hope I can figure this link sh.. out, I'm trying to learn html and make my first web site, if you know some good info out there for me for beginers let me know.

Thanks, Jason

Beaumont, TX

Where can I get a book on html ?

[This message has been edited by jaybird67k (edited 12-28-2000).]

I'm taking a web publishing class in school right now. I was doing some research and found a great HTML manual free to print off. It covers all the basics of the HTML. The site is Here.

Hope this helps ya out. HTML can really come in handy.

------------------

Me? I'm 15. I ride a 2000 YZ 426, and I luv it! In the winter, I ride a 1996 Yamaha XT 600. My whole family rides dirtbikes/quads and snowmobiles, even mom.

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Originally posted by motoman393:

Anyway if yall have any comments or hints on how to make my life easier i would appreciate it! Thanks,

Garrett

Checking:

1) I think the manual says to remove the radiators but this isn’t really necessary.

2) Make sure your head cover is clean before you remove it.

3) I use feeler gauges with bends in them but they still bind between a part of the head and cam lobe before they slide between the bucket and lobe. Don’t mistake the tight fit here as a tightness in the clearance. You may want to put another bend in the feeler gauge to make it easier to get them under the cam(s).

4) At TDC (compression stroke) the cam lobes will be facing away from each other (which allows the insertion of feeler gauges from between cams) and all four marks on the sprockets will be lined up, parallel with the head.

Adjusting:

1) You may need to pry off the cam caps, make sure you don’t scratch the cams.

2) There is a half-moon circlip under each cap on the bearing side (next to cam sprocket) that fits in a notch on the cam. You might want to have a magnet handy to catch this sucker when lifting off the cap to prevent it from falling into the motor. It is hard to grab with fingers only.

3) To remove the cams and chain tilt both up and out of the head at the same time, even with the chain tensioner removed the chain is too tight to allow one to be removed without the other. Reinstall in the same way, this is where marking the chain can really help you know where to position each sprocket in the chain before you tilt them down onto the head.

4) An alternate method is to count the links between outside sprocket marks (I think it is 14) and time one cam and then just count the links, i.e. install just one cam and time it, tilt it off and drape the chain over the other cam placing the appropriate # of links between the two marks.

5) After you lift the cams out the chain drapes nicely over the water neck (unless you left the hose on in which case a zip tie around this hose and through cam chain works well to keep it from falling into the head. If you do drop it don’t panic, just buy a magnet).

6) There are two dowels in each cap that go into bolt holes in the head. These may come off with the caps or remain in the head. In any case don’t lose them, they are necessary for proper oiling of the cams.

7) Some Yam service dept.s may have an assortment of odd-sized shims taken from various bikes they have performed adjustments on. Replacement shims are only sold in large (.05 mm ??) increments, if so inclined (type A personalities only) you can have clearances exactly in the middle of spec by fishing for an odd sized shim.

8) A magnet works well to remove buckets since it (usually) will remove the shim along with it.

9) Keep track of the relative location of each bucket and shim. Put the buckets back in their original location.

10) I have reused the rubber cover gasket many times with no leaks.

11) Buy a good torque wrench and tighten cap bolts to spec. carefully.

[This message has been edited by Hick (edited 01-02-2001).]

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