450 Cam mod (on WR426) how many pins??


60 replies to this topic
  • byggd

Posted December 22, 2005 - 01:18 PM

#41

Looking at the PDF I have and used to install my cam I count 14 :applause:

  • SXP

Posted December 22, 2005 - 01:32 PM

#42

The second pic with 14 pins between punch marks is CORRECT. The previous thread he referenced with pics was started by me during my cam swap and the bike had worked perfectly since.

Indy - With all due respect you are misleading the guy. As someone stated earlier the 450 cam swap on a 400/426 negates the alignment drill between the left punch mark and the surface of the cylinder head. Why the motor turned fine before he buttoned everything up is, however, a mystery.

  • SXP

Posted December 22, 2005 - 01:36 PM

#43

When you successfully rotated the crank by hand had you released/unlocked the cam-chain tensioner so that the chain was under tension? (you do know you don't have to take the entire tensioner assembly out, right?)

  • byggd

Posted December 22, 2005 - 02:10 PM

#44

Indy - With all due respect you are misleading the guy. As someone stated earlier the 450 cam swap on a 400/426 negates the alignment drill between the left punch mark and the surface of the cylinder head. Why the motor turned fine before he buttoned everything up is, however, a mystery.

Correct, the instructions state
"Refer to the pictures for setting cam timing. The 450 cam has two timing marks on it which won't
line up well with anything on the 426 head. (Figure 1) Check that the timing is correct by looking at the right side of the
cams. (Figure 2) They should look symetrical when installed properly".
http://photobucket.c...0cam_Page_1.jpg

  • NuckingFuts

Posted December 22, 2005 - 03:18 PM

#45

Satch has suggested that it may be my decompression actuation arm/shaft (which was left in the bike when the dealer originally did this mod to the brand new bike, seems they just took the cable and lever off only) which is getting in the way. Since the actuator is spring loaded I am still able to twist it by hand (hurts like a mofo) to make it press the ex. valve.

What I'll do is remove the actuator from the head completely and try to kick the bike over slowly while holding the kill switch (dont want to light it up with the open hole). If that works then I'll take another shot at installing the actuator (hopefully correctly). Sounds like I need that 'TT decomp plug' either way.
I'll update asap.
Thanks everyone!

  • SXP

Posted December 22, 2005 - 05:10 PM

#46

Satch has suggested that it may be my decompression actuation arm/shaft (which was left in the bike when the dealer originally did this mod to the brand new bike, seems they just took the cable and lever off only) which is getting in the way. Since the actuator is spring loaded I am still able to twist it by hand (hurts like a mofo) to make it press the ex. valve.

What I'll do is remove the actuator from the head completely and try to kick the bike over slowly while holding the kill switch (dont want to light it up with the open hole). If that works then I'll take another shot at installing the actuator (hopefully correctly). Sounds like I need that 'TT decomp plug' either way.
I'll update asap.
Thanks everyone!


I've left the entire decomp assembly in my bike after the 450 cam swap and it doesn't effect anything. I seriously doubt if that's your problem.

  • blue_beast_wins

Posted December 22, 2005 - 05:33 PM

#47

I cant see how the old decomp bit in the head could be the problem, i took everything off bar that myself, the return spring stops it from hitting anything,

First i would try to kick it over with the spark plug out, if it dosnt kick over then i think you may have another problem.

  • NuckingFuts

Posted December 23, 2005 - 01:41 PM

#48

Well I pulled the decomp shaft out and turned it over by hand. Pretty much the same. Tried to kick it over as well (very slowly) and Im getting a lot of resistance (more than I was getting before any changes were made) during the compression stroke......but I can kick through it without hearing any metal touching.

Now, with the plug out I can easily kick through just like I could before any changes were made. Cranks like butter, no irregular sounds or resistance.

Im wondering if the auto-decomp mechanism on the cam is now unable to do it's job completely being timed the way it is now. Almost as if its helping half way through only.

Though I can crank/kick through the resistance during the compression stroke when plug & decomp shaft are installed, Im VERY reluctant to test my luck with a real kick start.

What's your take?

  • NuckingFuts

Posted December 23, 2005 - 02:17 PM

#49

If you take a look at the FAQ page on Autodecompression:
http://www.thumperfa.../autodecomp.htm

See bullet #4 under 'Alternate Timings'

Because its so hard to kick over I wonder if this explains where Im at right now. Its confusing b/c my cam lobes, sprockets, and punch marks are all oriented EXACTLY like the pictures in the PDF instruction file (I can pick a dozen reference points on the cams and sprockets and they all match the picture).

  • blue_beast_wins

Posted December 23, 2005 - 02:17 PM

#50

Doesn't sound right, just a thought but did you check the timing with the tensioner in and are your last pics shown with the tensioner in, crank at TDC ? its kinda hard to keep the crank at TDC while your taking photos, thats the only thing i can think of other than it being other than a YZ cam.

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  • byggd

Posted December 23, 2005 - 02:21 PM

#51

Without reading back through the entire thread......did you go with 13 or 14 pins? I went 14 on my install and it feels odd when I kick it over (takes a bit of a push) but starts in 2 or 3 kicks and runs great.

  • NuckingFuts

Posted December 23, 2005 - 03:42 PM

#52

Without reading back through the entire thread......did you go with 13 or 14 pins? I went 14 on my install and it feels odd when I kick it over (takes a bit of a push) but starts in 2 or 3 kicks and runs great.


Currently set at 14 pins.

Is it harder to kick over than when you had it just past TDC (decomp still installed) and kicked?

I remember my first 426 (had the decomp) and it wasnt as hard to kick over as this bike is right now.

  • NuckingFuts

Posted December 24, 2005 - 01:22 AM

#53

Could have saved some time if I had found this thread before.
Im assuming there is no difference (concerning this specific mod) between the WR250F's and WR426F's.

http://www.thumperta...8216#post378216

To summarize the tread (if you're not into the nuts and bolts):

12 pins for a WR cam to be a YZ cam.
13 pins for a WR cam to be a WR cam.
13 pins for a YZ cam to be a YZ cam.
14 pins for a YZ cam to be a WR cam.


Im not sure where the "14 pins gives the YZ cam YZ timing" came from but the folks went the extra length to show otherwise.

Anyone care to challenge the info on that thread?

  • Indy_WR450

Posted December 24, 2005 - 05:24 AM

#54

Well now you are confusing the poor guy! :bonk: :cry: :cry: That post is old and has mass confusion just like this one! :cry:

If you want WR timing you need the WR 450 exhaust cam with the auto decomp. If you want YZ timing you want a YZ450 cam with auto decomp!
I dont think the guys in the other thread get that ( at least no back in late 2002 ) ! :applause:

Toby_S corrects himself by saying he went to 13 pins to make it work:

[COLOR=Sienna]Yes, I got it running and it runs perfect. Just like before. That's the final proof that the timing is right. To summarize:
It wasn't 14 pins between marks, it was 13. Forget about that anyway, and go by the punch marks that line up with the surface.
If you really want to be sure, set it up per the manual (punch marks aligned with surface) then rotate the exhaust cam counterclockwise one tooth. Make marks with a felt tip to be sure about it.
Also, I didn't calculate out lobe centers, but I measured opening and closing points, and the cams are definitely off by one tooth (22 1/2 degrees).
Now that I'm comfortable with all this, I'll probably try YZ timing someday.
-Toby [/COLOR]

  • Satch0922

Posted December 24, 2005 - 05:43 AM

#55

ok...here is where the confusion ends.

On a 98-02 WR/YZF with an OEM "YZ" 450 exhaust cam, to achieve proper "YZ" timing there should be 14 pins between the punch parks (witht he motor at TDC)>

The confusion starts when the WR450 OE cam enters the picture.

  • NuckingFuts

Posted December 24, 2005 - 09:22 AM

#56

Toby's statement (quoted by Indy) makes the most sense after having checked the angle of rotation for both timings. If the auto-decomp 'bump' is placed in each cam in a way that when the punch marks line up (or are at least close) then that's all you need to do in order to get the respective timing for each type of cam.

It seems if you took a YZ cam and lined up the marks you get yz timing. If you take the same cam and advance it 1 tooth you now have a yz cam with wr timing which is where I think Im at. It explains the added compression Im feeling on the kick start right now. (Sorry Indy I didnt explain that part before referencing that link with Toby's posts).

  • byggd

Posted December 24, 2005 - 02:42 PM

#57

I would go with the setting on the PDF I sent you (14 pins). I "think" they tested both 13 and 14 and 14 worked best with the wr intake cam. Just my 2 cents worth. Merry Christmas Eve All!!

  • NuckingFuts

Posted December 24, 2005 - 04:49 PM

#58

Update:

Rolled the dice on the 14 pin set up and gave it a hard kick through...........Houston we have ignition. Right from the get go I could tell the idle circuit was running lean where as before cam change it was just right. Looks like I'll bump up to a 45 from 42 next there. Bike no longer serged at constant throttle while I was warming it up down the street. After warm, it had my low end torque back and could loft the wheel (in 1st anyway) much better than before (not sure of why just yet). Roll-ons are just as crisp as before. But the downside, still have the bog at 1/2 throttle.

So, since Im looking at a jetting problem here I will install the YZ needle (EMP) and re-jet around that this time. That stock WR needle seems REALLY lean so there's no point in keeping it. Im also changing up to a Twin-Air filter since that stock filter seems very restrictive and may be part of the problem.

With that in mind, do you guys have any suggestions on starting points for jetting around the YZ needle?
Im heading off to the database for some ideas.

I just want everyone to know that I appreciate all the help and patience. Hope you all have a wonderful Christmas.

  • blue_beast_wins

Posted December 24, 2005 - 06:10 PM

#59

Glad to see after all that it wasnt a big issue, i ran the obeln needle clip#3 with 160mj 40pj 200maj 75 paj with the James now mod, worked pretty good.

  • byggd

Posted December 25, 2005 - 05:34 AM

#60

I have the JD kit so I'm no help with the YZ needle, but glad to here it started for you :applause:




 
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