YZ or WR how can you tell

Ok, this is going to sound really sad but it was my first off road bike and I have found reason not to trust the dealer I bought the bike from....

I bought a used yz400F and it had a WR gas tank and seat. IT WAS sold to me as a YZ and I have been trying to get it set back up as a YZ. I bought a new tank and have ordered a new seat but it has been hell finding the parts. I had assumed that the prev. owner set it up with a WR tank and seat for trail rides but with as much trouble as I have been having finding parts I wondered why the guy would go that route as apposed to using an IMS tank and the existing YZ seat. I am wondering if I did not get sold a WR in disguise.. The fenders are YZ for sure, there is no throttle stop as on the WR's but alas I want to be sure what I was sold is what I bought..

Does anyone know how to check this out? Is there somewhere I can run the serial number to find out???

I had a ton of motor work done and they spec-ed it to a yz but if its a WR there could be problems... It does not ride like it has the wide ratio transmisson in it as the gears are really tight but it does have a 51 tooth rear on it that could make up some of that difference.

Any advice or tips here?

pull flywheel cover tilt bike so oil does not leak out if it has 3 holes for bolts to go into flywheel you have a wr if the flywheel center is threaded for use of fly puller you have yz plus 18 inch rear wheel is wr and long brake hose is wr also you can call yamaha with vin and they will tell you wr or yz thats the first thing i would do

You can always take a look at your fly wheel and see if there is a magneito or stator.

Thanks for the info, it's got a short brake line and a 19" rear wheel. Looks like one and runs like one.. I think its a YZ.

I still like the idea of calling YAM with the VIN to be sure, I checked their website and could not find a phone number.

Anyone out there have it?

Thanks for the posting, it makes me feel a bit better and I think I will check out the fly wheel this weekend too.

I just did not want to be taken for a ride, excuse the pun. I guess I just wanted to make sure I when I thought I was buying an orange I did not get sold an apple.

I gotta go riding.. its been weeks and I am dying!!!

Call your local yammie dealer with your V.I.N They'll be able to tell you what you've got. Get the engine number also. Hey you wanna sell your WR tank and seat?

Thanks for the info parts man, I was looking all over and can not find the engine number.. where is it hidden at? I looked all over both sides of the case with no luck.

As for selling the WR seat and tank I probably will when I get a seat. I have had a heck of a time finding a used one or a new one at a resonable price. I found a used one for $130 and a new yam seat for $125 through HLMS online - said it would take 2 weeks to get it.. I just ordered one from SDG (bycicle seat guys) with a gripper cover for $89 but they have not started production yet.. They think it will only be a couple of weeks.. but I am betting on longer..

I hope when I get it switched over to yz stuff that the bike will corner easier as well as jump a bit better.

I took a big double the other day for the first time and when I landed I ended up with a lot of gas tank where I don't want it if you know what I mean. I am very much a novice dirt rider but I am learning quickly. I just can not get the cornering thing down yet.. I hope getting further forward on the bike will help a bit. Probably just saddle time is the only thing that will help.

Anyone have thoughts on gripper seats/riding styel etc? I currently slide up and back on the seat a lot (good or bad??) and after several hours I get a little of the monkey but going and am worried I am getting into something worse with the gripper..

Originally posted by partsman:

Hey you wanna sell your WR tank and seat?

I've got a WR tank and seat (in good shape) that I'm looking to get rid of. Email me at wilbot@hotmail.com

Originally posted by Tom N:

I was looking all over and can not find the engine number.. where is it hidden at?

It is on your crankcase, just behind where the chrome oil delivery manifold feeds the tranny and just above the kickstarter. There is a machined flat area on the casting, look at the top right of the first case halve in this picture. If the cases were ever replaced this pad will be blank.

As for which thumper you’ve got why don’t you just check the first gear ratio? Someone may want to check my math, but I’m thinking that YZ first is 19 revolutions at the crank for 1 at the wheel (19:1) while WR first is 25:1 (both calculated for 14/49 sprockets). Yank the plug or have a buddy hold the comp. release, mark the wheel, put a wrench on the flywheel and count the turns.

At the countershaft we’re talkin’ 5.45:1 YZ and 7.13:1 for the WR (Crank rpm : countershaft rpm). I think :)

Originally posted by Tom N:

Anyone have thoughts on gripper seats/riding style etc? I currently slide up and back on the seat a lot (good or bad??) and after several hours I get a little of the monkey butt going and am worried I am getting into something worse with the gripper..

I love my N-Style gripper seat, the pliant nature of the material made installation easy and the cover is very durable. I don’t like the seats that are partial grippers, I’ve heard guys complain of them coming apart at the seams, the shiny graphic side panels get discolored over time and with taller foam they don’t line up with the graphics on your tank.

Some off-road guys say grippers exacerbate the monkey-butt thing, but for me they help save a lot of energy, especially in conjunction with my Factory Effex tall (and soft) seat foam. The two combine to really plant my butt “in” the bike which may be the key to avoiding monkey-butt, but I think growing up horseback made me impervious to it, I’m not even sure what it is (but the term is descriptive enough, thank you).

I know you didn’t ask, but here’s a riding tip anyway: your goal should be to learn to use your legs, thighs, knees, and feet to keep you on the bike (IMO a gripper will help you accomplish this), not your arms and hands, you need those to steer, and you can’t do that if you’re constantly yanking and shoving to maintain your balance. Pretend your gas tank and radiator shrouds are a thighmaster, squeeze tight and you won’t collide with the gas tank.

As for turning I think the YZ seat and tank will help tons, you can almost never be too far forward when cornering.

Hope this helps.

Thanks again for your wisdom Hick, you are always there for us rookies..

I will do some more checking on the case but looking at the diagram it should be easy to spot but I did not see it. If all else fails I'll try to count the turns on the output shaft as you described.



I may be wrong but can't you just look for kickstand mounting points on the frame. The YZ doesn't have these does it?

Wilbot, thats what someone else said to look for and I did but could not tell if it was there or not as I did not know what it looks like.

So far everything except the tank and seat is looking like a YZ, it's got the right exhuast pipe, fenders and size of wheels on it. I don't see any indications that it ever had an odometer on it and it runs like a scalded dawg... I would think I would notice a difference in the gear ratio even with a 51 tooth rear on it. The gearing is so short in fact I often never use first gear (it's too short) and I can rap it out on the top end very very quickly - almost too quickly as there is not much top end (compared to my friends KTM SX400 with it's 6speed). I think I need a smaller rear sproket maybe a tooth or two... What was stock, my manual indicates 49 but I have seen other material that indicated 47??? anyone know??

I believe stock is 14/49. I run a 14/50 on the mx track and a 15/50 out in the desert.



When in doubt, GAS IT!


I forgot that first and second gear on my YZ426 are taller than a YZ400, so the info. I posted is not accurate for the YZ400. I’m pretty sure the WR is correct though, but if it is a YZ you will get more than 5.45 crank turns in first, but it should still be considerably and noticeably less than 7.13.

Sorry 'bout that.

[This message has been edited by Hick (edited 03-06-2001).]

Originally posted by partsman:

Call your local yammie dealer with your V.I.N They'll be able to tell you what you've got. Get the engine number also. Hey you wanna sell your WR tank and seat?

Hey PARSTMAN, I have a WR seat and tank that is for sale, contact me if you're interested.


You are correct Khris/sirhK (I just figured that out).

Stock WR is 14/50.

As for first gear it is possible that someone put YZ gears in your WR (or vice versa). I wouldn’t worry about it too much, if it turns out to be a WR then so what? The wide ratio may be better for your riding and many WR owners end up with YZ plastic, jetting, cam timing and seat/tank.

Two theories, a YZ owner who wanted a bigger tank or a WR owner who wanted YZ fenders and rear wheel. The first makes more sense to me, finding a used WR tank is probably easy but I tried for a long time to swap my rear wheel for a WR one and never found any takers. Since the 18” works fine for motocross (I heard KW and others used them at Glen Helen and other nationals last year) I can’t see anybody going through the trouble to find a 19” (unless another YZ off-roader like me talked them into swapping).


Sounds like you have a YZ, but if necessary, you can reach Yamaha of North America at 800-962-7926.


Thank you all for the help, I called Yam yesterday and gave them the frame number and the engine number (I did find it hick, well hidden though). They confirmed for me that the Chasis and motor are YZ and that they were the factory mates meaning they left together. Wa-Hoo!!!

Not that I would have been disapointed to own a WR but I just had the motor reworked and speced as a YZ and was woried about probs..

Anyway I am still converting the seat and tank back to YZ - got the tank and could not find a used seat so I ordered a new one from SDG ($89) but its back ordered until late April. Many asked if I was interested in selling the WR tank and seat to which I might be once I get the new one. I'll let ya all know...

Thanks for the help gentlemen - hey that reminds me, how come I have not seen any ladies post on this site? What's up with that?? :)

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