I think I may NEED to YZ time....

16 replies to this topic
  • Dodger

Posted August 19, 2002 - 05:07 AM


First off, my bike runs awsome (knock on wood), starts easily, pulls stong top to bottom, good jetting, no fouling, all mods, yada yada......

This weekend I was staying with a moto buddy of mine, he lives at 10,600 around Breck, and has an '00 YZ426. I helped him rejet his bike this weekend to get it to run a little better. He's never jetted it for his altitude, he just kept changing plugs as necessary :) . Once done, I hopped on his scoot and took it around his property. This isn't my first time on a YZF, I owed one last year for 3 1/2 months. But damn, I THINK I REALLY NEED TO YZ TIME MY BIKE!!! The punch it put out compared to my WR was unbelievable, it's exactely what I'm looking for.

My question is this, before I go and YZ time my bike, does any/everyone think that I'm currently getting everything out of my WR that I'm supposed to be getting??? Sorry, kinda vague question. The deal is that my bike seems quite a bit boggier than the YZ I rode. I haven't done the BK yet, honestly I don't have too much of a problem with stumble off idle with a quick whack of the throttle. With the understanding that I'm loosing some power being at elevation, it seems that I have to work a bit at lofting the front except in 2nd or mid 3rd gear. Other than that, I can forget it. I guess I was just wondering if I will need to YZ time to get that superior boost of power that I felt in the YZ, or am I just not getting everything out of my WR that I could be. If so, I would be open to suggestions. BTW, I will be doing the BK mod soon.

Sorry, long dumb question, I just want more POWER!!

Dodger :D :D

  • comp182

Posted August 19, 2002 - 05:33 AM



  • John_H

Posted August 19, 2002 - 06:06 AM


Hey Dodger,
I've been thinking/talking about YZ timing for a while myself. Just to let you know...any time I've ridden a YZ or YZ timed WR I've felt the same way. Seems stronger everywhere, especially from the bottm up.

  • Dodger

Posted August 19, 2002 - 06:20 AM


Comp182, good point. I suppose that would have some impact on where the power hits, even with a WR, you should be able to find that point in each gear regardelss though.

Ok, so the big question is........How tough is changing the timing on these things. I've studied Garrett's (Motoman393) web page, it makes it look like CAKE! Will I need any special tools to make the change?? Are there any points to pay particular attention to so not to screw it up (i.e. installing carb slide upside down for example).

Anyone who's done this, I would like to PM you a few questions.

Thanks all as usual....

Dodger :) :D

  • Pozi

Posted August 19, 2002 - 09:14 PM


Originally posted by Dodger:
Ok, so the big question is........How tough is changing the timing on these things. I've studied Garrett's (Motoman393) web page, it makes it look like CAKE! Will I need any special tools to make the change?? Are there any points to pay particular attention to so not to screw it up (i.e. installing carb slide upside down for example).


You are right in saying that it is "cake". I was reluctant in doing this mod myself. it's just one of those feeling you have to overcome. But now that I have done this myself I feel a little more confident in doing other engine work.

Special tools? Nah.

The following is nothing new just what I have gathered from the TT before doing the mod myself:

Points? It is very important that you do not lose the retaining clip into the crevous of the engine when you pull the cam cap. I did not encounter this but I have read this from serveral others that it happened to them.

I would also mark where the WR timed chain and gear line up with a Sharpie. Just as a back up for potential mistakes.

This is coming from memory but there should be 12 (vs 13 w/ WR timing) chain pins between the marks on the cam gears after you are done.

I haven't heard of the carb slide thing you mention though.

Good luck!

[ August 19, 2002, 12:16 PM: Message edited by: Pozi ]

  • Hick

Posted August 19, 2002 - 10:46 AM


The YZ timing probably won’t make better dyno numbers but it seems to “get there” that much quicker. That sounds like the sensation you were describing. As for the gearing that is a difference, but w/ stock sprockets third and fourth are very similar WR vs. YZ.

If you haven’t tried a YZ needle IMO that is AS big a difference in roll-on power as changing the cam timing.

Changing the timing isn’t any harder than changing the needle IMO, just more involved.

I think in the “valve shim” section of the manual, which is the basic process we are talking about, it says the radiators must be removed. It is a tad more difficult getting the head cover off with the radiators on there but definitely possible. Another tip I’ll offer is it is handy to have one of those small telescoping magnets around. That way if you drop one of those clips, or lose hold of the cam chain, it is no big deal to fish it out of there, especially the latter. What I do is have the magnet handy as I remove the cam cap, and use it to snatch up the circlip before it can sproing (Look! A new word!) off there.

With the tensioner off you can lift the cams out of the head, to create enough slack in the chain to move the exhaust cam one tooth lift both cams out and set them together with one wheel sitting just behind the other. Then just pick the chain off the exhaust wheel and move it forward one tooth. As zey say en France zen, voilá!

One last thing, do NOT over tighten the cam caps. It may be difficult/impossible for you to get your torque wrench on the middle bolts of the intake cam. Just remember 10 NMs isn’t very much at all. Make sure the clip is in place and the cap is snug to the head before you tighten…

  • Dodger

Posted August 19, 2002 - 02:21 PM


I've got a dumb follow up question.........!!!

You don't need to drain your oil, right?? I'm just curious as to if there was enough oil in the case, as to pour out when you unscrew the cam caps to line up the marks. I'm way off here arn't I?!?

BTW, used to be that I would just unsrcrew the caps and see if oil pours all over the floor, now I come running to TT.......... :) !

Dodger :D :D

  • Hick

Posted August 19, 2002 - 03:49 PM


Originally posted by Dodger:
I've got a dumb follow up question.........!!!

That is actually not a bad question at all.

To be safe fire it up for a second just before you do this, but I have never had oil come out the center plug in the mag cover when checking valves etc. and actually never thought about that possibility...

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  • skthom2320

Posted August 19, 2002 - 04:28 PM


It is very important that you do not lose the retaining clip into the crevous of the engine when you pull the cam cap. I did not encounter this but I have read this from serveral others that it happened to them.

I'll second that. I adjusted my valves myself. Thirty hours of riding time later, the clip from the exhaust cam found it's way into the timing chain cavity and locked up the engine. Oops.

I dodged a bullet though. No damage whatsoever. It just got caught on the chain when I stalled in a corner and made it so I couldn't kick it over. I thought I had siezed the engine.

Just be absolutely certain that clip is in the right spot.

Anyone need a mechanic? :)

  • XC800.X

Posted August 19, 2002 - 04:53 PM


Don.t forget to wire tie the chain to the intake cam. One less thing to worry about. :)

  • Dan_Lorenze

Posted August 19, 2002 - 05:40 PM


Dodger, I think you should just do it.. You'll like it. You sound like a guy that could use the extra umph..... good luck, and if you do it let us know what you think...


  • Christie

Posted August 19, 2002 - 11:49 PM



  • tbronc

Posted August 20, 2002 - 01:25 AM


Again, be very carful when reinstalling the bearing caps.

I'd get some moly assembly grease like the manual says. Tighten them in cross-pattern, a _very little_ bit at a time.

7.3 ft-lbs!

If you do it wrong, you WILL gaul the bearing surfaces of the caps, and possibly the cams as well.

-Most stupid thing I've done on a motorcycle.

I felt alot better when I heard that some very respected mechanics made the same mistake.

  • Dan_from_HB

Posted August 20, 2002 - 05:20 AM


Go ahead and do it. It's not nearly as difficult as it seems. Just pick a day when you have plenty of time, don't get in a hurry, and keep it really clean inside.
You know how all that dirt gets into the wiring harness under the tank? Wrap it in cling-wrap before you open the valve cover to keep dirt from dropping into the head. You will dislodge some dirt.
Use a torque wrench for reassembly, and check valve clearance again before buttoning it up. You'll like the results.
I haven't rejetted, but I expect that would boost power even more.

  • Dodger

Posted August 20, 2002 - 05:36 AM


So in searching the archives, I see a number of posts that say going to the YZ needle makes almost as much of a differance as the timing change. Anyone want to chim in with their $.02??


  • wrooster

Posted August 20, 2002 - 01:36 PM


doing the timing change is actually quite straightforward -- it took me about 40mins on my wr250f and there were no surprises.

i do have a couple of hints: 1) use clean new motor oil, not MOLY assembly lube, when you put everything back together. since the engine and transmission share the oil in our F's, that MOLY lube will eventually end up on your clutch plates. which isn't what you wanted. 2) use saran wrap plastic food covering to wrap everything up before you start. once you get the tank off, you'll have a lot of dirt/grit/sand just waiting to fall into the soon-to-be-open valve and cam area. so before you open her up, wrap the frame, radiators (yes you can leave them on), and everything else north/east/west of the engine with saran wrap.

good luck, it's easy.
jim aka the wrooster


Posted August 20, 2002 - 08:20 PM


after a few days of watching this post i finally decided to yz time my bike last night. it was cake to do but i'm not sure how much i like the outcome. i did notice a decrease in low end and a small increase in mid to top end snap. i still have the stock jetting in my ride so i'm hoping if i mess around with that, things will be a bit more noticeable.


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