Opinions on YZ timing a WR.....

I was thinking about YZ timing my '02 WR426 and wanted to get some opinions from you guys as to performance gains, any drawbacks, or just plain is it worth it. My bike is running killer right now, and I kind of hate to mess with a good thing. I have read posts where everyone is happy with YZ timing, but what do you guys think about losing some bottom end, or hard starting or anything like that. I am not a mechanic, but am willing to take the time to figure it out myself. Its not that difficult is it? Any reason not to do it? I am a woods/off road rider mostly, so I'm thinkin' that this will be a good mod for me, as long as I dont lose too much bottom end. Thanks for the input.... :)

I love the YZ timing on my bike. I also had a 98 WR that was YZ timed. You do lose a bit off the bottom, but I like the way the bike builds rev's now, seems to work great in the woods(that's all i ride). You'll probably have to re-jet also. Do it you can always go back if you don't like it

In my experience it doesn't affect the jetting, although it may unmask a jetting problem that is already there. The two bikes I've tried this on already had jetting almost identical to my YZ.

The low end feels weaker, but that may be due to the very strong run up into the mid range. I can ride a long wheely more confidently (I suck at wheelies) on the WR due to the smoother transition. I can see where in limited traction situations the WR timing has an advantage, but other than that I see no real reason not to try it.

Hope this helps.

Do it!!!

You won't miss a thing and on those huge gnarly hill climbs......just open the throttle and lean forward........then get ready to shift up as you head up the hill :D :D :D :D :):D

Well, mine is YZ timed, and it is great, lots of power from low end up, but gobs "up"! I have no idea what it was like before, I bought it used and it already had all the mods everyone speaks of here in this group. I even toned it down by installing the air cleaner lid back on. I was more concerend with water getting into the inlet then the extra horsies. I already have gobs of power now!

Whilst you are at it, install the YZ450 cam with the autodecomp feature. Well worth it all round.

I was thinking about doing a YZ cam in my WR. I rode a couple of YZFs this weekend on the trails and I loved the way they revved. I want that type of revving on my WR!

YZ timing will reduce torque and responsiveness below 4000rpm, however provide a steeper HP vs RPM response through the mid range, with some top end improvement.

The best way to recover the low rpm response is to add a Power Now/James Now... from personal experience this device results in a YZ timed 426 being as responsive (if not more responsive) as the WR timed version.

As per other posts a slight rejet may be required with the timing change (mine needed to go leaner)

In my opinion YZ timing in concert with James Now is the best combination for this motor, its tractable, controllable and responsive.


I YZ timed mine and I'd never switch back. Mid range and top end are much stronger and I didn't notice it being any more difficult in the tight stuff.

I can ride a long wheely more confidently (I suck at wheelies) on the WR due to the smoother transition.

This is so true!!!

On my WR426 I decided to time the bike to YZ spec just to see what all the talk was about.. Im my personal opinion I feel that the YZ spec makes the bike "faster" up top. It really makes the motor come alive in the upper revs. What you lose it throttle control.. I feel that in tight sections the WR timing is better. The WR426 tends to be a handfull in tight sections as it is stock, YZ timing your bike will make it worse and your bike will be more prone to stall. The best word to decribe the YZ spec is "hollow".

I'm one of the only members here that thinks WR timing is better.. I can ride though,tight rocky sections with more confidence and better throttle control with stock timing..

If you're looking to make your bike faster, someone mentioned a YZ cam with auto-decompression... This would be the way to go.. The auto-decompression is one of the best things about the new 450's...

good luck..


Dan would be the one that I would listen too, and I agree about the stalling and that the throttle gets a bit more twitchy but I still disagree with him on this overall. However, I have gone to a 13 tooth front sprocket just due to the elevations I ride. This, of course, makes a huge difference in the low end tractability for the tight stuff.

In the last enduro (only) I rode, I was having no problem, lofting the front wheel or making tight turns directly into steeper uphills. At 250lbs out of the shower this setup had no problem pulling me up anything I can think to ride up. I would agree that she does get a bit touchier about stalling though. but with the immense power gain at higher revs I think its a wash.


I agree with you. Dan! :)

Since I'm able to jet my Euro to get a really nice mid-top rpm hit, I'm wondering if the Euro versions already YZ timed?

Anybody know?

I doubt that. I know that Canadian versions are not YZ timed from the factory


YZ bikes is yz timed

WR bike is wr timed

YZ bikes is yz timed

WR bike is wr timed

Yes, this is true.....

Thanks for the reply. Looks like I'd really like the YZ timing then because I like a strong mid-top hit.

Did anybody mention that Josh Demuth "wr times" his YZ450 so the power is a little more controlable on the arena cross tracks he seems to dominate?

One thing to take into consideration for us is the fact that we ride at altitude. At 13,000 feet, my 426 feels pretty slow compared to someplace like Moab at 4,000 feet. The YZ timing probably doesn't make it as unmanageable here as it could be at sea level.

John. My yz400 felt like a slug ridding out by you at 8,000-10,000 ft. I thought I was on a 250f at times.

You mountain folks need to come down here to sea level and see what your bike can really do. :)

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