DirtRider . Net MX, SX, Arena Cross, Off-Road Community

This is the text version of DirtRider.Net
Click Here for the Full Version

Pages: 1

Best mods for wr/yz400/426
(Click here to view the original thread with full colors/images)

Posted by: Henrik---------------------

So - which are the best mods? Are there any mandatory mods??

Posted by: a454elk---------------------

I just bought a 99 WR400 and the mods done are cutting the gray wire (? ask around for what they mean) and an aftermarket airbox was installed. A pipe is supposed to help as well but it makes it louder. I need a steering damper to help with high speed stability. Other than that, it runs great and has lots of torque.

Posted by: JasonJ---------------------

Must do mods:
Air box lid, gone
Baffel or stock WR pipe, Gone but with consideration to noise
Gray wire, cut
WR Seat and tank, replaced with YZ style large cap tank
Dunlop front tire, gone
Carb, jetted right and BK mod (see link below)
The bike is great stock and a ripper with a few free mods. It dose not take much money to reach max potential. The motor rocks, suspension and brakes are top notch. If you have a WR you might want to re time and rejet it to YZ specs to see how you like it. There is also talk of dropping an 03 WR Exhaust cam into earlier models to give it the auto decomp.
This and other atrosities you can performe to your bike in detail at www.thumpertalk.com
Enjoy your new bike! its a Ripper!

Posted by: CAL---------------------

Definately retime the WR to YZ specs.  Made a huge difference on my dad's WR!  You can get step by step instructions from Thumpertalk.

Posted by: a454elk---------------------

What exactly happens to it when you do that? Do you lose the low end torque that helps when cooming out of corners in 3rd gear?

Posted by: CAL---------------------

You don't loose anything.  But you gain alot throughout the entire range, with the biggest gain in the midrange.  Dad says he can come out of a corner better now, and can lift the front over obstacles much easier.  The WR's exhaust cam is retarded by one tooth on the cam sprocket as compared to the YZ.  Move the exhuast cam one tooth to YZ specs and you now have a YZ with a flywheel weight.  Throttle response is MUCH better.  Dad's WR already had YZ jetting, grey wire mod, airbox, and uncorked muffler.  After changing the cam timing, I could hear the difference in the "crispness" of the engine as soon as I fired it up the first time.  Well worth the time (2 hours for me) and cost nothing.

 

Posted by: Rich Rohrich---------------------

Quote:

Originally posted by CAL
The WR's exhaust cam is retarded by one tooth on the cam sprocket as compared to the YZ

In the stock configuration the WR's exhaust cam timing is ADVANCED compared to the YZF. Basically they are opening the exhaust valve about 23 crank degrees sooner and reducing the overlap. They did this in an attempt the start the blowdown phase earlier to balance out the super restrictive stock exhaust configuration. If you change the cam timing to YZF spec it's important to also run a less restrictive exhaust setup. It's a MUST DO modification in my opinion. If you plan on completely uncorking your WR it's worth it to change over to YZF jetting as well.

Posted by: CAL---------------------

My bad.  There's my mistake for the year.

Posted by: Rich Rohrich---------------------

Quote:

Originally posted by CAL
My bad.  There's my mistake for the year.

LOL :confused:

Posted by: JasonJ---------------------

As far as I herd from Yamaha dealers and sales folders the WR timeing was to give it better traction in slipery stuff, but Rich's explanation sounds more likely. It IMHO did track better in snow and wet rock, ect with the WR timing. The YZ timing hits right off the opening of the throttle wich makes it hard to deal with in rough slipery terain like going through creek beds but to me the YZ timing is still better in the tight east woods because you NEED to be able to lift the front tire in a split seconds time to clear downed trees and big boulders, someting the WR timing cant always do in lower trail lugging RPM with out a clutch slip or down shift. The front suspension will get you out of ALOT of trouble there but at slow speeds even smaller trees can unhourse you if they are wet or on an odd angle and the front tire catches the greased rail,,, Ahhh!
Most guys feel the WR is more likely to stall with YZ timing but I always keep my idel up a bit high to avoid the deadly Hi comp 4 stroke sputter stall.

Posted by: Rich Rohrich---------------------

Quote:

Originally posted by JasonJ
It IMHO did track better in snow and wet rock, ect with the WR timing.

Which makes perfect sense. Starting the blowdown that early kills the expansion cycle and torque with it. So the usual pipe tuning dip around 3500 rpm is muted , but so is the big torque rise that follows (the hit you feel with YZ timing).

Dual range ignition systems like the Vortex essentially do the same thing with their Traction settings by causing peak cylinder pressure to occur too late to produce maximum mechanical advantage. Less torque at low rpm usually translates to less wheel spin in the slippery stuff. It's really pretty simple once you take the marketing weasel pseudo-tech out of it.

Posted by: a454elk---------------------

So with my stock exhaust, you don't suggest changing the timing? Next question, who's coming over to work on the bike for me? 89er won't answer his phone now, wtf!!

Posted by: Rich Rohrich---------------------

Elk it's not a very good idea, you'll end up with weird glitches in the fuel curve that will be tough to work out, and the engine will tend to run hotter. You could probably go with one of the end cap /SA solutions like the Pro Moto Billet piece ( http://www.mxsouth.com/promotobillet/pmbyamcap1.htm ) and strike a happy medium between noise and flow, but I haven't tested this personally.

Posted by: Henrik---------------------

Pipe - we are talking the hole thing from the head and backwards, not just the silencer???

Posted by: Henrik---------------------

Sorry, not pipe, exhaust system...I was thinking in 2-stroke terms.

Posted by: a454elk---------------------

Thanks Rich

Posted by: Rich Rohrich---------------------

Quote:

Originally posted by Henrik
Pipe - we are talking the hole thing from the head and backwards, not just the silencer???

Henrik - On the US models the silencer comes with a very restrictive end cap. To reduce the exhaust backpressure there are solutions ranging from end cap inserts to complete systems depending on exactly what you are trying to accomplish.

Posted by: Henrik---------------------

Ok, so I went to the local Yammie dealer today. The pipe from the head to the muffler is the same on YZ and WR, (U.S Canada and Europe - not sure about Asia atleast '01). So - it's the muffler that kills it. So all you have to do to "uncork" it is to change the muffler. I was afraid that I'd have to change the whole thing...But - I'm curious. Has anyone tried running a WR YZ-speced (grey wire unhooked, YZ camtiming - anything else??) with the stock WR muffler? (Tried = several dynoruns) If so - how much gain does the YZ muffler give you? Also - which is the best aftermarket silencer?

Posted by: CAL---------------------

My dad has been running his WR with all the common mods (including YZ timing) and an uncorked stock muffler.  Never had it on a dyno, but it is "relativley" close to YZ performance.  If it were me, I would get a stock YZ muffler.  The uncorked WR muffler isn't much of a muffler when it's uncorked.  About 2/3 of the muffler is just open cannister with no core with the restrictor removed.  It is also louder than my YZ with stock exhaust.

 

Posted by: JasonJ---------------------

I run the stock WR muffler with the baffel out. Yeah its kinda loud but no where near being an open header. I want to try one of those plated end caps or a Vor tip, you can make your own tip for under $5 fron a bit of exhaust bend pipe and just deflecting the exhaust at the ground is supposed to make it more quite.
The YZ muffler is a good buy if you can get one used from a YZ racer BUT,,, the YZ muffler from what I understand DOSE NOT have a spark arrestor and thus may make you not leagal to ride in certain areas, so its someting to think about.
Whats the best slip on pipe??? Who knows, very little objective testing I have seen based on Dyno runs with noise factors listed. I have herd the FMF Q (quite) core is a nice and light pipe. Me, Ill run the stock WR pipe uncorked untill a good light quite pipe emerges with proven numbers,,, I dont know, I dont think the uncorked WR pipe is that loud, but then again I dont ride behind it either. As Rich said, the sales weasel tech in the pipe market is about as beliveable as the listed dry weight of the WR from Yamaha,,,,,.
One nice thing about getting an aftermarket header is the bends of them usally allow you to change the oil filter with out breaking the header loose.

Posted by: CAL---------------------

Quote:

Originally posted by JasonJ
One nice thing about getting an aftermarket header is the bends of them usally allow you to change the oil filter with out breaking the header loose.

'01-'02 stock headers clear the oil filter.

 

Posted by: JasonJ---------------------

Quote:

Originally posted by CAL

'01-'02 stock headers clear the oil filter.

 

DOOOHHHH!

Anyone want to sell a stock 01 or newer WR header??? I know some one out there has one sitting like new because they HAD to put the lighter Ti one on right?

Posted by: CAL---------------------

Check Thumpertalk.  There all over the place, there.

 

Posted by: Henrik---------------------

I never thought there would be so many mods.......Hmmm...I wonder - are there similar mods for other brands or is this just a Yammie thing? Don't get me wrong, I'm a Yammie fan, I'm just curious. Or are these mods just to be concidered as small things you can do to make it even better, the downside beeing tha EPA or T.U.V (if you live in europe) won't rally smile when the look at your bike????

Posted by: JasonJ---------------------

Several mods like chuck the WR baffel and airbox lid or snorkel and Oh yeah, almost forgot,, CUT the THROTTLE STOP if its even on your bike, are must do free, fast and easy. The rest make the bike better and are free if your willing to do them like the gray wire, YZ time, others are cheap like BK mod, the Most money I spent on my WR to make it better was the seat tank combo. I would even consider the $150 bucks or so to drop the 03 WR 450 cam in for the auto decomp more of a luxary creature comfort but well with in the budget for the big blue beast this year. My main other expens has been keeping decent rubber on the rear of the bike Zoom Zoom Zoom!!!!!!!!!!!
Mods for other bikes? yeah they are out there but I think why your seeing such a well documented set of mods for this bike is,
a. The bike was plugged up from the factory with stuff they (ment) for you to remove to let the bike see its stock potential.
b. The colabarative efforts and organization of tinkerers compiling there finds and experiments on the web, ala Rich, Thumpertalk, ect. Welcome to the age of digital information!!!!

Posted by: vznx1w---------------------

The best mod for the money is to install DP Pro-MX front brake pads. Waaaaay more front brake power to get stopped when jumping the double with a short landing into the next turn.

Posted by: Ol'89r---------------------

Quote:

Originally posted by a454elk
So with my stock exhaust, you don't suggest changing the timing? Next question, who's coming over to work on the bike for me? 89er won't answer his phone now, wtf!!

Hey, Carlo.

Just twist that little handle on right side of your handlebars a little harder. :scream:

More power, :confused: your startin to sound like Tim Taylor.

Ol'89r
Home phone number unlisted.

Posted by: a454elk---------------------

Well now that the bike is finally broken in by a fine rider like myself, I'm up for some power additions since it feels like a fitty now!!

And to think, you told me there were only 3 gears, you're a real funny old guy!

Posted by: mikeolichey---------------------

I have an 01 YZ250F and an 01WR250F. After the free mods on the WR, I did the following other mods. They are listed in order of how happy I am with them:

1. 03 YZ exhaust cam, YZ timed. This is a must do. Not only is it very easy to start the bike, but it will not stall as easy, and bumpstarting is a no-brainer. About $100 from Steits.com, and 1-2 hours to install, at most (1 if you have checked/shimmed your valves and know your way around).

2. EFM autoclutch ($650). Unbeatable in nasty terrain.

3. YZ-style seat ($90) and tank ($200, I went with the Ty Davis 3.2). Many times I just run the stock YZ and can go 80-85 miles on 2 gallons. I have constantly been amazed at these bikes' mileage.

4. Steering Damper (WER on WR and Scotts on YZ).

5.DrD exhaust ($450) Better throttle response, a little more power, less weight and a S/A

6. Vortex ignition ($400) Probably wouldn't do this again. Not enough bang for the buck

Other Personal preference items I like: GTY-R (more forward) T-clamps, Fatbars, remote hotstart, Panoram computer, hand/Rad/frame guards, Acerbis dual headlight.

Since it was time to freshen up the top end I am trying Eric Gorrs 262 kit. I have also heard good things about the Powernow, but have not tried it myself.

Posted by: JasonJ---------------------

Mike, since you run both the WER and Scotts dampeners on very similar bikes, whats your take on the two and wich do you think is the better value for a trail rider if you dont mind me asking.

Posted by: mikeolichey---------------------

They both work well. The WER is nice for its location, you won't faceplant into it, and its cheaper. The Scotts is easy to adjust while you are riding, and if you are going to use it on more than 1 bike, it takes only 2 bolts to switch.

Posted by: JasonJ---------------------

Is the WER adjustable by hand while you ride or is it a PITA?
I think this will be my next $ spent on the bike, even before an 03 cam

. I do very mixed riding and can go from rocky woods trails to sand like coal dust loom and high speed but rocky power lines in a matter of minutes.

Posted by: Ol'89r---------------------

Quote:

Originally posted by a454elk
Well now that the bike is finally broken in by a fine rider like myself, And to think, you told me there were only 3 gears, you're a real funny old guy!

:scream: WHAT! You mean there are two more gears in there. :confused:

So far, riding with you I've only had to use three.

Posted by: DEANSFASTWAY---------------------

Man o man a revloc auto clutch (or other brand ) help turn that violent , tight woods staller into a giant minibike that is so fun to ride and resistant to stalling.

Text Version Home

This is the text version of DirtRider.Net Click Here for the Full Version

Best mods for wr/yz400/426

This is the text version of DirtRider.Net
Click Here for the Full Version