ALL(?) the 400 mods all at once.... Results:

13 replies to this topic
  • Chaindrive

Posted May 26, 2003 - 08:20 PM


'99 WR400: Spent the last 1 1/2 years gathering info and parts. Went from stock with airbox lid removed and throttle stop cut to: (all in one shot):
1) YZ450 exhaust cam (modified timing)
2) Big Gun tapered exhaust
3) P-38 accel. pump housing
4) Grey wire disconnected
5) YZ needle ('99)
6) Stock YZ jetting ('99) 168 main 45 pilot, then:
7) Better YZ jetting: 162 main 40 pilot
8) James-Now mod
9) air screw 1 1/2 to 2 turns out

Results after 3 days at the track: :D
1) EASY to start!!!! Love this!! Could do cartwheels about this!!!!! My kid can start it now!!
2) Snappy
3) Cuts out mid/high (sometimes?!)
4) I'm not honestly real impressed with the power delivery. I wanted to be "scared sh!tless" I guess... instead I have to "intentionally" work for a wheelie..? Big Deal... It did as well or better before... Maybe the modified cam timing doesn't help? It is supposed to be in between WR and YZ "hit". There just is NO "hit". I don't seem to have the "rheostat wheelies" (dial in your favorite height with just the throttle) that I used to.
5) The bike really sounds cool!!!

1)I am NOT that good a rider.
2)But I DO know how my bike has always ran (basically stock) and ability has never dampened desire. I go hard till I crash and then try it again. When I crack the throttle, I want that baby to LAUNCH!
3)The still-stock suspension sucks so bad that at 60mph the headshake was so terrible that my 9 year old on a KX 65 fed me rocks!!!! I HAD to back off, and NOT 'cause of the rocks in my face; the bars were being ripped from my hands by headshake!! Same story on the track: (The 60mph+ was on what most would call a "fire-road".): No control. And, yes, I DO have an accurate speedo.

I say "stock" suspension meaning: nothing more than the max oil level in the tooo-soft-bottoming forks; which has caused a major oil seal blowout I discovered via the puddle on the trailer floor after the trip to the track... I also have @ 1" left of the threads on the rear shock to gain "recommended" sag.

The throttle response is initially good. Craps out part way through (SOMETIMES) (like hitting the rev-limiter at mid-rpm). It never needs the hot start. Starts real easily even when doing "50cc patrol": meaning riding a little ways, shutting it off, waiting for all the little guys to pass (maybe helping a couple), then moving to the next "trouble spot"... Hard on any bike, I know. That is why the starting impresses me. It never fails.

I also know that all the power in the world is useless with crap suspension, but I really have doubts about spending big money on suspension for this bike when all the power-mods don't impress me more power-wise. I read what everone says... I MUST be doing something wrong..?

1)The easier starting alone is worth every penny and effort!
2)The "new" power is honestly a disappointment. I already own a DR650(PUKE!!) and don't need a clone... My WR (WZ?) is actually a little better than that (what isn't?), if only because it is 100 lbs lighter.: My WR now reminds me of my old XL500 power-and-suspension-wise...(It was cheaper, lower, and street-legal too!) Suggestions? :)

  • oRGie

Posted May 27, 2003 - 01:23 AM


sorry i cant give you any advice on how to better your bike, but your post has confirmed for me that I made the right choice. I had a 98 wr400, mainly in stock condition, a bit untidy. I totaled up all the mod work and restoration work needed, seals, springs etc and instead decided to go for a wr426 instead (after seeing posts on here from 426 owners). More power and suspension that really works. All I've done to mine so far now is take out the airbox baffle thing and I can dial up my wheelie height up to 3rd gear without any effort, 4th and 5th still require a good yank on the bars, so I've got a yz needle on order. But I can now really scare myself, which is what i wanted when i decided to go for the wr400 in the first place. I need to brace the steering tho, flat out on tarmac I can just about keep it going in a straight line, wants to go into a tank slapper, no speedo so no idea how fast its going, but its damn fast :) (current fav hobby is showing up cbr900 owners on the twisty mountain tarmac roads around here :D

  • jchantzWR400F

Posted May 27, 2003 - 04:27 AM


Well, I wish I could say exactly what the problems might be, but I can't. :) The only thing I can say is that I haven't done a lot of the mods you've done (see below what's been done to my 99 wr400), but I can tell you that mine never cuts out, never has trouble getting a wheelie in 3rd (just a roll of the throttle) and I'm 6'1" and 225 lbs. Sometimes, when I have the power hit in 3rd it does scare me sh*tless, and will ocassionally break the tire loose on dry dirt. On top of that, my bike has always been easy to start. I have been thinking of doing some of those mods, but know I'm having second thoughts. I would bet, that someone here will make a jetting recommendation. :D

  • Guest_Guest_*

Posted May 27, 2003 - 05:17 AM


Looks like you went the wrong way on jetting, I run a 178 main and a 48 pilot. I'm 6'2" 240 and can wheelie in third.
And the bikes good to 5000' in elevation..just my 2c

  • Chaindrive

Posted May 27, 2003 - 06:03 AM


Yeah. I am hoping some jetting will massage the miss/stumble/cutting-out out of it. I will try some different needle clip positions since it seems to be right in that rpm/load range. It doesn't do it all the time if I "finesse and baby" the throttle. But who wants to hold back?

I had been waiting a long time to be able to take it to this particular track to test it out. It is a big, high-speed track and he also has miles of woods trails and a great "WFO private dirt road" (drag racing, anyone? :D). Hard to find all that around here. The suspension problems were actually the bigger problem.

At least I garnered some envious looks from stock 400/426 guys in the pits going through the thumper-starting-ritual while I just gave one effortless kick :D! Now I know why 450 guys look so pleased with themselves all the time :D! Mine starts easier than most of theirs even. (I shortened the kicker for my lack of hip flexibility which also happens to give me faster cranking speed)

I am going to try to clean my fork seals with a negative or whatever, reset my oil levels evenly and lower them, then drop the forks back down all the way in the clamps to try to gain some stability so I can wring the motor out better through ALL the gears. Hard to evaluate fully when I am forced to back off due to steering/suspension.

It is interesting that there is a post on the YZ forum describing a similar problem and some replies saying it is just something you have to learn to live with on all these Yammies..? (a mid-range stumble)

It is kinda embarrassing :D. Loud, sweet thumper pulling away through the gears...then: akakakakak (how do you spell that crappy sound anyway?)

As for the power delivery: maybe it is there but too smooth to impress? I call that boring. :D I wouldn't even be afraid to Armor-All my seat :D!

I can crack the throttle and wheelie or hop a small ditch (great response off idle) through the early gears, but it just doesn't seem capable of lifting and holding that front wheel a few inches off the ground through sheer mid-range roll-on torque and acceleration. I love that feeling and headshake wouldn't be an issue if the front wheel wasn't on the ground! :)

I should know better than to make more than one change at a time, but I hate repetetively tearing it back apart to do them one at a time. Whatever it takes; I am definitely in no position to buy a new bike and I am pretty fond of this one. Besides, me and my license plate MUST remain the thorn in the Iowa DOT's :D !

Daudisio: My plugs were black and sooty before. The color is getting much better as I go leaner. How do your's look with that rich of jetting. Mine was nearly that rich before the mods.


Posted May 27, 2003 - 06:21 AM


Not that big of a deal really.... First , get RID of the YZ Needle and order an OBEKN needle and set it on the 3rd clip. The EKN Needle is an explosive needle and will resolve the wheelie problem. Next, Match your jetting...the 40 Pilot goes with a 75 Pilot Air Jet. It sounds like you have a 100 Pilot Air jet which causes it to be overly lean and stumble in the mid-high end of the range. (Also indicated by your fuel screw setting of 1 1/2 to 2 turns out...trying to compensate) You could actually go leaner than the 40 to a 38, but would have to drop the Pilot Air jet to a 65 in order for it to work properly.

As for your 65 MPH head shake. First check the track of your front wheel. Do this with an ink pen taped to a can and placed as close as possible to the rim. If the lateral runout is more than lets say 1/4 of an inch, then get out your spoke wrench and bring the wheel back into true. (or as close as possible anyway). Also check your head bearings for play... Put the bike on a centerstand, have someone hold the rear tire down and then, standing in front of the bike pull the forks toward you... If you feel any give, replace the bearings and the races (Easy to do) If all this is ok, then raise the fork tubes up in the clamp exactly 1/2 inch...(this seems to settle the bike at high speed, and also allows for wicked tight turns and makes rear wheel steering very fast), aside from that you can always purchase a steering dampner which will positively eliminate headshake forever.

Good Luck...

Bonzai :)

  • Chaindrive

Posted May 27, 2003 - 07:57 AM


Thanks, Yamakaze :D! I just got off the phone and ordered the OBEKN. (When you say 3rd clip, are you meaning from the top?). I actually do have a 75 pilot air jet in right now, but I ordered a 65paj and a 38 pilot jet while I was at it, so I will try that. Going from a 45 pilot to a 40 (smallest I had) did help the stumble somewhat (previous owner had a 48 in with the 75..?), so maybe the 38/65 combo will cure it.

I have, right now, the OBEJP on the middle (4th) clip, a 60 starter jet, and a 200 main air jet to go with the currently installed 162 main, 40 pilot, and 75 PAJ. I should have mentioned the full jetting specs before, sorry.

Where should I want that fuel screw set with the OBEKN, 65 PAJ, and 38 pilot? Also, do the main air jet(200) and 60 starter jet sound right? The previous owner was into this carb ahead of me and he seemed to like things "different" :)...

I will check out that front end as you described. It probably is in one or more of those areas since it never used to do that at high speed. I just figured the oil leaks caused uneven oil levels and weirdness.

The steering damper is next on my wish-list right after a pro-suspension job. I even already have the clamp, mount, and tower for a Scott's. Got a great deal right here on TT for those AND a Zip-Ty rear link as a package deal! I have been bargain hunting and slowly gathering parts for a long time... Time for some pay-off! :D The boys aren't chasing D-22 MX points this year, so we want to try some more Hare-Scrambles and such... fun stuff and more to my ability and I want my bike ready!

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  • yamaha.dude

Posted May 27, 2003 - 11:01 AM


Have you ever changed the gearing on your bike... may be the issue with the apparent lack of power...

Headshake could be a number of things, but get thoise forks fixed and you will have a good basis for working out the problem...

Good luck,


  • BrandonW

Posted May 27, 2003 - 11:19 AM


Hey Chaindrive,
You did what I did: Everything all at once.

The only thing that stinks is that if it is one thing out of whack, you don't know where to go.

Good luck in sorting it all out. You already know the benefits of the cam!


Did you ever see my post about the Seahawks getting Seneca Wallace? Was he the guy you were touting as Iowa's best QB, or was that Banks? My Hawks picked up Wallace in the 4th round, so I am hoping it was him!

  • Chaindrive

Posted May 27, 2003 - 01:13 PM


ARRRRG! Brandon! How could you remember that?!!! Man is THAT embarrassing :D after the performance the Hawks gave in the Bowl game (thank you all for not rubbing it in as I deserved)! It was actually Brad Banks (UI) that I bragged about (thus jinxing him I suppose :D). But when Seneca Wallace (ISU) is hot, he is REALLY hot! :D Glad to hear he found a home in the NFL. Up until the Bowl game, ISU was the only team that beat the Hawks early last season before the Banks Machine got rolling.

I will not give up on the bike. There is too much to like about it. It is asking a lot to hit the the right jetting on the head with the first try or two. That is one subject here on TT that I am only now beginning to understand (a little) by doing despite having read so much. The boys' 2-strokes are easy compared to this carb. Glad I am not the only one to take a big bite all at once! I know you have your's where you like it. And there are many much-wiser than me here to help fine tune! :)

Jets and needles are relatively cheap, so I need to consider my extended weekend at that track with the WR more a success than disappointment since I learned from it. Besides, the boys had fun and did great with two 5th place trophies, one 1st, one 2nd, and one hard-earned 1st place overall Series Championship... that's a lot of hardware against some great competition!! Seeing so many friends we haven't seen for so long was icing on the cake. :D


Posted May 28, 2003 - 04:57 AM


Where should I want that fuel screw set with the OBEKN, 65 PAJ, and 38 pilot? Also, do the main air jet(200) and 60 starter jet sound right? The previous owner was into this carb ahead of me and he seemed to like things "different" ...

Once you have those jets in place the Fuel Screw should be between 1/4 and 3/4 depending on density altitude/Temp/Humidity for your area. The 60 Starter jet may be ok. However if you roll on the throttle and black smoke exits with the choke pulled, then...go down to a 55. I run a 55 in summer and a 50 when the temps drop below 40 degrees.

Bonzai :)

  • R_Little

Posted May 28, 2003 - 05:29 AM


Don't know what is up with yr motor.

My 2000 400 pulls great low and mid with similar jetting -
(EJP in the winter and DTP in the summer), plenty of wheelie power w' WR timing. The YZF I rode was just explosive! Yours should be the same. Mine is a first kick starter, no sweat.

As for the suspension, have you ever had it rebuilt? My bike can head shake a little when decellerating in big braking bumps, but nothing serious. Sounds like you have no static sag in the shock and the forks raised in the clamps, that might make it twitchy. If your 4 yr old shock is blown or low on rebound you might get a lot of swaping.

Maybe its time to get the shock looked at?

BTW I also own a modded 96 DR650 and think the power is similar to my WR just heavier as you say. I was always amazed how the throttle response on my DR w' a CV carb is perfect and the WR with it's high tech FCR always needs tweaking to remove the bog!!!

  • Chaindrive

Posted May 28, 2003 - 12:23 PM


Thanks guys! I'll get sorted out on the steering/suspension well enough to test the new jetting once the parts arrive. Then I will find a way to come up with the bucks for some real suspension work :D.

R Little, I have read such claims from other DR650 owners... Wheelies even :D!!?? Under it's own power :D?!!! I would have to see it to believe it! :D Comparing my DR to my WR is alot like comparing my Cummins Dodge to my '69 Camaro :D. Maybe I'll have to play with that bike a little... :D I can't seem to sell it, and it IS the most dependable, solid-rock (emphasis on "rock") of a bike I have ever owned.

Nothing but a slip-on SuperTrapp right now. I have nearly bent the bars trying to PULL the front wheel off the ground before! It needs WAY lower gearing and that goofy 525 chain/sprocket size really limits availability. But 100 mph is easy if you can control the front end! Too scary for me. Come to think of it; that is perhaps the only time it's front wheel has ever tried to leave the ground... :)

  • R_Little

Posted May 28, 2003 - 02:53 PM



Dont want to make this a DR650 forum, but if you are around No. New Jersey come take a ride on mine. W' a 14 CS sprocket I can pull 2nd gear power wheelies straight up and grab 3rd from time to time. The DynoJet kit and Yosh pipe give it about 38-40hp I guess like the WR. I ride it on the trail and it goes pretty good. It is about 20lbs lighter than stock though. It's actually pretty fun compared to the stock bike. Good on the street too.


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