wr426 cam timing again...

15 replies to this topic
  • SFO

Posted February 12, 2001 - 05:56 PM


Ok, I have the cover off of the cams.
At tdc a black mark is in the inspection window.
The intake cam has marks at 9, 12, and 3 o'clock.
The exhaust cam has the same markings only they appear to be one tooth advanced.
To make the exhaust cam marks appear at the same dispensation as the intake cam I would have to turn it one tooth clockwise...
The instructions aren't exactly the same for the other years...
Am I upon the true path?
It is my goal to create yz timing btw...
Thanks, bill

  • bonez34

Posted February 12, 2001 - 06:40 PM


on the 2000's they come stock with 13 chain pins between the 12 o'clock dots. you just want to rotate the exhaust cam 1 tooth clockwise to get 12 chain pins between the dots. i wouldn't go with eyeballing the positions of the cams. this will be correct if they are the same as the 2000 models!

  • SFO

Posted February 13, 2001 - 06:36 PM


13 to 12 is the **** .
It was at 13, now it be 12.
Will have to burn a couple wheelies up bryant st. to check it out.
Thanks for the help.

  • Taffy

Posted February 13, 2001 - 08:53 PM


put a zip tie around the inlet sprocket & chain so that it can't slip. when you startlifting & shoving you'll say to yourself 'did the chain just slip-or am i imagining things!'.

with the inlet 'locked' you can fiddle about until you get it right.


  • SFO

Posted February 13, 2001 - 09:36 PM


It is done.
The power seems brighter in the region of mid-top.
I heard that a pipe will accent this.
I am eye-balling a yosh ti set-up.
A distributor owes me a small favor...
Has anyone experienced this pipe?
Damn, I feel like such a ducati queen asking about titanium parts...
Forgive my transgressions, o lord...

  • Michael

Posted February 19, 2001 - 10:48 PM


Okay SFO.....have you had a chance to ride it for real yet? Can you notice a significant change in the mid-range punch? Was the bottom-end affected? Inquiring minds want to know! Thanks for you info.......

  • Taffy

Posted February 19, 2001 - 01:18 PM


Michael are you serious?

this whole website is dedicated to reports on every conceivable aspect of YZ timing.

some of it analitically done by very good mech riders. go to the 'discussion archives' & read & read & read & read.

you don't have to have on eriders view there are 50!!!

anyway, good luck.


  • Dan_Lorenze

Posted February 19, 2001 - 04:34 PM


Taffy, Taffy, Taffy!!!
There you go again!! Its funny, last week we really didnt know if the WR426 had the YZ timing but all of the sudden we now have 50 or so archives on the WR426?? Relax my man, My 426 hits way harder than my 400 does and in my opinion I dont think that the 426 really needs the fix as much as the 400! Michael, great question dude, If you have the 426 I would leave it alone...

Even if this was a redundant question I wouldnt really care, I like hearing from new people, you cant blame them for being excited, I wouldnt want the WR forum to turn into the ever exciting XR650R forum zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz Dan :)

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  • SFO

Posted February 19, 2001 - 05:37 PM


The bottom end is less bright....
Carnegie, where I went riding, has a mx track and alot of hills w/nada traction.
This is not my fav riding spot.
Anyway, at this point I would say the giving up of the bottom end is a wash, considering that even on the mx track I would only spin it up a few times.
I am going to try Hollister this wknd and will have experience in known trails to actualy quantify a difference.
Its still 50/50 at this point...
I am considering adjustable cam sprockets so I don't have to utilize the coarse 1 tooth adjustments...
The crisp ripping bottom end is missed....

  • Michael

Posted February 19, 2001 - 10:03 PM


SFO - I was going to head out to Carnegie (I'm in San Ramon) myself today - but as you said that place rarely has the best traction and the adobe mud is a real pain if you don't give it three days after a rain.

You are the second person that I know of that has posted on the timing change on a 426 (sorry Taffy I must have missed the other 48 :) ). Neither you nor Parry in Clovis seemed to realize the benefits that the earlier years did - maybe that will change when you can open it up a bit.

Thanks Dan - it's the price of being a relative newbie. My focus was the 426, and I haven't heard anything yet that makes me want to consider a timing change. I made the switch to the E series needle, and hope to try those changes out this week - so far so good.

Taffy - I should have been more specific in my question, as I know there is a sensitivity around here to posting about FAQ's without doing a search. Anyway, I accept my beating with a smile :D, and I continue to respect your posts! You have a lot of insight into these machines we all ride (I appreciate that) and an occasional hair tigger with rebukes (ready, fire, aim). It keeps things lively!

  • Taffy

Posted February 20, 2001 - 07:17 AM


i am only guessing but bigger cubes usually means more midrange torque etc. the YZ timing just makes it better everywhere because the exhaust valves timing on the wr is outside the range of any sensible engine builder.

you should get more power everywhere (certainly no loss i wouldn't have thought) but especially the mid upper.

what often isn't explained is the way the revs just keep going up & you keep having to shift gear.

in many ways there is too much power after it's done.

last year i did the timing & raced the next day. i managed to turn every 180D corner into a 270D.

you're right though, we are only just getting used to the fact that it's NOT got the YZ timing OTD.


  • Polo

Posted February 20, 2001 - 08:06 PM


Got my WR425 out over the weekend for 3 days at the sand dunes. It seems a lot more responsive right off the get-go but doesn't seem to rev. up like my 2000WR400YZtimed bike did. I miss the high rev but love the instant response. Is this the bigger CC's talking or YZ timing or both? I want the High rev of my 400 and the instant torque of my 426. It's sounding like YZ time the 426 may be the thing.

Has anyone raced a true YZ426 side by side with the WR426? I guess I just want it all. Keep posting new WR426 feedback please. :)

  • Dan_Lorenze

Posted February 21, 2001 - 07:38 AM


Polo, Your question was if anyone has raced a YZ426 on their WR426? I did last weekend. I got into a drag situation with a friend and I belive that the YZ might hit a little harder for just a moment but the the WR (WR timed) will hook up and finally catch up and when it comes to 5th gear? Forget about it the YZ is toast and is forced to shut down because of gearing. We also climb a massive sand hill and the YZ will not make it and the WR will, I know this because my friend and I always climb the same hill every weekend with the same results, by the way he's the better rider! I also got to ride my brothers WR250F, the thing is sooooo hard to ride, It has no bottom end and your forced to ride it wide open, too much work for me! I need that lazy-man low end pop! See Ya later, Dan

  • Taffy

Posted February 21, 2001 - 11:11 AM


well i've moaned about the size of the carb on the wr/yz but it's just a bloody joke on the 250. 37mm on a 250? as usual it's the american infatuation with bigger is better & 'horse power numbers'.

no offence to all on this site but that has got to be what this is all about.

i'd love a 37mm carb on mine that's for sure.


  • SFO

Posted February 27, 2001 - 04:56 PM


Taffy, talk to phil allen for a 37...
Tell him I said hi.

  • Taffy

Posted February 28, 2001 - 12:11 AM



i'm not going to spend silly money on mine & i would guess that a new carb is silly money.

what would be far more realistic is if someone's mate has purchased a WR/YZ 250 & for the sake of an hours work they put the 37mm on the 400/426.

i think it would open a lot of eyes. we have far too many passive members in the group so it'll come down to the same one or two.

just think of all that bottom end umpphh!



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