Going back to WR timing... YZ timing blows.


I thought the same thing a long time ago. I went to YZ timing and hated the lack of control I had. I had so much trouble in Moab when I first went to YZ timing. I was down quite a bit when I'd give it gas in a tight spot and it would take off on me.

Before I went back to WR timing, I tried the 52 tooth rear sprocket on the advice of a T-Talker. Made all the difference in the world in control. I was able to control the bike in all the ugly spots. Then as I got use to it, no more problems, except when my ego gets bigger than my abilities :)

woah, taffy pull the camshaft out of your exhaust port and take a chill pill. we may not be all rocket scientist perfect engineers like you are. i am struggling, working my way through college, at a local grocery store to pay off my debt for my pride and joy, better than new (used) 98 wr400. i love this bike, and had it a lower seat height and weight, it would be the only bike anyone would ever need. most of us never use more than half of the 50 hp available to us at the turn of the throttle anyways. we may feel like we are moving like MC or #199, but in fact, we are not balls to the walls professionals like you appear to be. people come on here to share their views (as the poster of this topic and i have concerning wr timing) and ask for advice because we are not as all knowing or experienced as you. if we all had the oportunities you do to perfect our bikes, there would be no need for this forum. true?

please have a little more curtosey next time your time of the month comes around and you read someone else's opinion that doesn't agree to yours. they are entitled to it.


p.s. i am not trying to cause trouble with you on this one, and i hope you don't feel the need to reply with another "factual" report of my inability to give 100% of my time to riding, because this is what you call constructive criticism.

You know what guys, at least for me this whole exercise with YZ timing and mocking around with the jetting is the fun part of owning a bike. When I was 13 (30 years ago!!) I had my first bike and I customize the hell out of it. 4 months later when I finally screwed up the poor bike I asked my dad for another new bike, he said that he will buy me another bike if I sign a contract that I would never touch a tool or customize the bike. Well, of course that is one contract I have been breaking for the past 30 years and over 26 motorcycles.

I see Taffy’s passion for perfection, I also see myself (Gray hair does this to you) and some of you who are asking why MUCK around with something that works well for a small gain in performance. BUT it is fun to mess around with the bikes. I have 6 motorcycles (street and dirt) sitting in my garage and anytime my wife complains about them I tell her: you rather deal with 6 other blond, brunet and red hairs or the beautiful bikes that are sitting here and not asking for ^&*^&.

Seriously, the valuable information provide by all of you will help us to make not necessarily better, faster bikes; but, ----- inspire some of the new comers to the WR family to make decisions that they may like or not and then, learn from it.

OOPS, Gotta go back to another stupid teleconference.

Has anyone had any luck getting cam information from Stroker? I've sent them numerous e-mails and even called them for the specs on their "Torque Cam" and "Rev Cam". The guy on the phone said he did not know and would get back to me. That was several months ago. E-mail queries have gone unanswered. What's up with that? Also, what ever happened to having a cam ground to your own spec's? I remember my old man having cams made with certain lifts and durations when I was a kid. Does anyone do this anymore? There is a lot more to cams than just timing.

Dan, I would really like you to ride my WR. I know you have invited me to ride on several occasions and I will take you up on it soon. I recently rejetted with Taff & JD's recommendations. I was under the impression that my bike could not run better, but after having a go at it I was blown away by the improvement. It took awhile to dial it in, but now I'm able to run taller gearing and it has way more pull though the gears than it did before the rejet with 14/50 gearing with gobs of top end. I'm also running a 10oz flywheel weight. It mellows the YZ timing "hit" and made it more trackable for me.

I'm defiantly sticking to the YZ timing. Me like.

ps: What ever happened to OTBA?

Web-Cam makes most of the cams for the So-cal guys, and they do a great job considering they have a master style grinder instead of a CNC cam grinder.

Laurie, Steve, and Debby are all good people.


There is also some talk of another guy doing some new grinds with CNC equipment.


I think there is more available with the right grinds but it will send us back to the drawing boards for a complimentary pipe design.

The CNC grinders allow us to isolate the base circle from the duration, for one. Actualy being able to modify the duration and lift while maintaining the same base circle offers the grinder a lot of latitude in one off designs.

First I want to do a 2mm stroker crank, then I will dig back into the cams...

I ran the stock ignition minus the grey wire and the vortex ignition back to back on the dyno(I hope that word doesn't offend any on e in particular)

There was only one difference, the vortex had the yz rev limiter at 11.5k instead of 10.5k of the wr.

I didn't know that this issue was resolved.

My measurements show the yz cam timing to be typically 106 lca on both the intake and the exhaust.

After cutting the barrel base gasket surface I realized that what I had just done would modify the cam timing again so I went ahead and installed the falicon adjustable sprockets and after some deliberation came up with 105 in lca and 106 ex lca.

I also found that my 44o cc motor like a small main (155-165) coupled with the ekp in the middle.

All of my midrange gurgling has been resolved by moving to a smaller main.

I tried a bunch of different fuels and oxegynating compounds blended in with different jetting.

I would be happy to send all of my data to anyone who is interested, I just have to plug my friend Dale Lineweaver(Pace pro singles championship tuner).

**** i only pissed a few of you off this time, i'm really losing it. mark my book as "must try harder"!!!

glad you didn't all walk away from this. it's so easy to come back with "i'm busy" and one of you did but as i pointed out and will repeat, with 5,0000 blinkin members out there we must have one person prepared to go.

SFO the main jet can be used as a guide to your porting and valve sizes (ie gas flow)but i'm sure you know this.

i've heard someone say before that there is a difference in ignition and i maintain that i don't think there is.

SFO, nothing wrong with a vortex ignition. it's just that someone else ran them on the dyno (WR v YZ ignition) and said there's no difference.

BTW. people say that there is a difference because they use different part Nos. but i THINK that every year every model gets it's own part No.

see boys, the jury is out. so stand firm men, shoulder to shoulder and ? the ignition curve difference.

SFO, great #'s (Nos) on the cams. one thing i do know is that SFO's bike will produce more peak power than mine. the neare the numbers are to 110d the better. it would now nice to try 110d and even 112d.

which cam needs to move? inlet or exhaust?

my indexed wheels have had 1d marks put on them by my engineer simon. all i would need to do is;

tank, seat off, jet wash and blow dry and perm. rocker cover off and then undo two 10mm bolts to adjust the cam. probably each mod would need to take 20-30 minutes. if you stick to the road you could do lots of little changes and when you get a feel for what is working you then take it for a proper dirt ride. knowing what you tried you can then go in the right direction.

i also think that my 14/48 and 15/48 is higher than most of you and so any real lack of torque i see is quickly exposed.

you must always get your jetting right before you do anything else. the WR and the YZ timing will barely change your jetting.

it's your exhaust, air filter, airbox lid that make the most difference. a yz timed bike shoul;d run leaner by (i'm guessing 2-8 on the MJ) like i said; not a lot.

once you initial cam timing is done by a shop (they won't show you) or a mate(he will) you can move the wheels yourself.


a good shop will see what's wrong with a grind straight away if they've done it long enough. it's often history with the manufacturer using the same grind and having the same failings on all their models. the answers therefore t themselves.

ron, stroker have played that game for over a year. that really is out of order (1 1/2 years possibly).

as for those that don't feel they can offer too much i say this;

do you agree that the YZ tank top profile is the best?

do you want to still hold three gals?

why didn't you back the call or help start it now for that very tank?

would you still be happy with 2 1/2 gallons if it could be done?



Further to the YZ/WR CDI ignition timing curve issue; I have a fische card for my bike (2000 WR) and from what I can tell by using Yamaha's "Where used & reverse superceded" programs the U.S. - spec. Y2K WR 400 has it's own CDI box, while the rest of the world uses a different box. Additionally, the CDN./Euro./Jap. CDI is the same for the '00 WR 400 and the '01 WR 426, but different again for the U.S. 426. Has any one ever taken U.S. & CDN. WR's and back to back, hooked each up to a tach and timing light and seen if there was any vast difference in ign. timing advance at various RPM? That would settle it once and for all.

BTW - it is not my experience that Yamaha issues different part numbers for different model years. If the part is common to different years, models, or even product lines, the number remains the same. To do otherwise would be a logistical nightmare for Yamaha and thier dealers.

If you don't believe me, the next time you need an oil filter, order one for a 1987 Yamaha Big Bear 4x4 ATV, or if you have to replace your ign. coil, just order one for a '99 YZ 250. All the same part numbers. P.Z.

I have only done a seat of the pants comparison between a US spec. 00' WR400 and a Canadian spec. 00' WR400. Gearing, Pipe identical. Jetting stock on both bikes. The Canadian bike was noticeably stronger. Not like a man and a boy but a noticeable difference. I'm not sure if the grey wire mod. had been done to the US bike. If not this is supposed to make a nice difference and could be the equalizer.


P.S. One thing that just dawned on me. The US WR was YZ timed so that throws everything out the window.

[ December 12, 2001: Message edited by: Mike in Silicon valley ]

Yes Taffy the YZ tank is far superior than that of the WR period... and yes if I could get a 2.7 gallon tank with a YZ top and something like a clark tank bottom I would buy one. The TY Davis tank in my opinion is a bit extreme.Nice effort though. Kudo's to TY.

Cam timing, is it going to make that much of a difference to overcome rider ability. I think not...I like most of the yanks haven,t had the pleasure to ride with you, but I am certain you use every horsepower available that can be produced and need more. I Know I do.... thats why these guys are buying these larger displacement bikes because they are using all the WR has to offer and its just not enough. If I only had the money for one of these larger more powerful bikes then maybe I could keep up. :D

Thats my story and I am stick'in to it, HUGE


it's just a bit of fun to play with these bikes isn't it?

howard, i'm not using all the power because i ride tight woods and there's no raw power there.

if i lived in cali i would ride your baja deserts and plead for more BHP.

i need grunt. i'm only a clubman and anybody who knows me knows i've only ridden dirt since feb 2000. i need to touch the throttle and shoot forward without changing gear.

i need to pop the front wheel like you can with a two-stroke.

if you ride only 50 yds between corners you need bottom end power. this bike is essentially a MX bike.

it's been changed to an enduro machine at no extra cost. the extra machines sold make it into a profitable machine.

yamaha are going to have to become enduro specific when they bring out the 2003 machine.


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