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WR450 De-Restriction and Conversion to YZ Spec Street Legal Machine

341K views 492 replies 77 participants last post by  dave ls1 
#1 · (Edited)
I recently purchased another '09 WR450 and it came completely corked up as they do from the factory. Regardless if you have a '98 WR400 or a brand new '12 fuel injected WR450, this thread will provide some helpful insight on what to do to get your machine to how it should have come from the dealership (minus the carb and jetting for the fuel injected bike(s) :lol:). I also thought that I would cover what is required to get to a "street legal" status...or pretty close anyway due to differences in laws between states. Hopefully this will shed some light on just how easy it is to get one legal and running like a true 450. I will also provide part numbers where I can. Keep in mind that these bikes are street legal machines in various other parts of the world, so most of the components and the wire harness are already set up to adapt the bike for street use and makes for a simple low cost conversion. I will also cover some other things like tire/rim sizes and chain blocks. I'm still building the bike, so this thread will be a work in progress for the next few days or so.

So to get started, here's the bike:







First things first, as soon as I got it home and out of the back of the truck I began disassembling since the bike was so choked up that it wouldn't get out of its own way.









As with any new bike, one thing that gets overlooked is the steering head bearings and the swingarm linkage. They do NOT come adequately greased, if at all, from the factory. So the first item was to break out the tub of grease and drop the forks, rear shock, and swing arm.



While I was tearing the bike down, I went ahead and removed the AIS pump and lines and installed the AIS block off plate. At this point, if you have an aluminum framed bike and are going to install a horn, the former AIS pump location is a great place to mount the horn.





After some scrubbing with a scotchbrite pad and WD40, it was time to re-assemble some of the bike:



Since I was working on the handlebars, I went ahead and installed my headlight switch:



Here's the part number and information on the headlight switch. I'm not too worried about a horn or turn signals on this bike, so a hi/low beam and kill switch is all that I am concerned with. This switch is plain, simple, and has a clean look to it:



I also installed the hydraulic brake switch:



When I get the bike the rest of the way together I plan on installing hand guards. This is why I chose to go with the "low profile" switch. It costs a little more, but also makes things a lot more simple when clearance becomes an issue.



I will also be installing a keyed ignition which I will get to later once the mail man brings it by.

So now it's time to get to the heart of the bike and what makes or breaks it...the carburetor.





The steel frame bikes offer easy access to the carb which makes jetting an easy affair. However, with the aluminum frame you have to tear half the bike apart to gain access. That being said I was reluctant to use the jets that came in the GYTR AIS kit since the main jet was a #175 which is a pretty rich main. Not wanting to have to do this twice I also ordered a JD Jetting kit as well...mosly for the needle. I will try to give a little bit of info. on why I chose the particular products that I am installing on my carb as I go along.

Included in the AIS removal kit is a shorter throttle stop. Since the cover was already off, I started with the throttle stop:



This is a picture just for a comparison:



The next step is to remove the float bowl. Once that is done, the fuel advance rod will need to be removed. I didn't take a picture of it, but it connects to the black plastic arm in the upper part of the carb by the throttle stop area and runs through the carb body down to the fuel advance side of the float bowl. You'll need a pair of basic pliers and simply pull it straight down to remove it.

Now since one of the big short comings of the FCR carb is the dreaded bog, there is a simple solution/fix to it made by R&D Racing. The name of it is the Power Pump and it is basically an adjustable leak jet. You also get another vital component to make the carb run correctly, which is a stiffer fuel advance spring. Since I was working on this part of the carb, I went ahead and installed the spring:







Now it's time to install some more appropriately sized jets. The JD kit comes with relatively detailed instructions. In my case I have just figured out which jets work best for me through lots of trial and error, blood, sweat and a lot of foul language. My elevation is about 600' so I went with a #50 pilot jet and a #170 main. Here are the respective locations of the jets:



While you're this far into the carb, it's definitely a great idea to check your float height. Per the manual, it calls for 8mm from the bottom of the carb body to the top of the float. Once again this is just some simple insurance for peace of mind:

(note that the camera angle makes the picture/float height look kinda off)


With that out of the way it's time to address the float bowl. Now the purpose of the circuit in the float bowl is to feed fuel to the fuel advance. Fuel is pulled through a check valve and is pressurized by the diaphragm which is activated by the arm which is connected to the throttle turnbuckle. Confused yet? The other part of this system is the leak jet. Now in most cases a bigger jet number would be a larger size/more fuel. In this case, the leak jet allows some fuel to bleed back into the float bowl. This means that the smaller the leak jet number/size=more fuel being advanced. To dial in a leak jet you would normally have to pull the float bowl off to make an adjustment. With the R&D adjustable leak jet you can simply make any adjustments externally with a flat blade screwdriver.

For installation of the adjustable leak jet you will need a punch and a 2mm allen wrench.





Now flip the float bowl over, it's time to install the final piece. You will want to make sure that the diaphragm spring is on and that you install the o-ring (from the bottom housing that you removed to gain access to the diaphragm) in the new adjustable leak jet.





Now you're ready to button up the bottom end of the carb and off to the needle.



You'll remove the plug from the top of the carb slide assembly.

Remember this thing that you found in the tool kit that came with your bike (if you got a tool kit with your bike lol):


Well this is what it's for:




Place the clip on the recommended slot on the appropriate needle and re-install. I also bought a R&D flex jet screw. This gives easy access to the fuel screw and also prevents it from ever falling out.

 
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#38 ·
Is it the power shot 3? I have installed a couple of the power shots. They don't seem to be as effective since there's no adjustment (I can't remember if the 3 is or not). Make sure you get a stiffer throttle spring as well. The leak jet and that spring are both tied to the bog.
 
#40 ·
Congrats on the sticky!

FYI,

I was going back and re-reading this thread and must have skipped over the part where you refer to the "TPS Fix" the first time i read that post. I thought i was going to have to re-jet my carb to fix that sputtering/cutting out feeling from the engine under constant throttle until i read that. I didn't know that was the cause and how easy of a fix that is. I'm going to do that mod tonight.

Thanks for saving me alot of un-needed aggrivation and work!

This is the thread of the year. lol
 
#45 ·
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#50 ·
Probably a stupid question... Sorry in advance lol. A couple months ago I bought a WR fmf pipe and pwr bomb header, and haven't installed it yet. After reading this thread i keep thinking that maybe I should get a system for a yz. I would think that they are the same thing, but maybe the wr pipe is more restricted? Like I said dumb question but I would sleep better at night knowing my wr will be all it can be lol
 
#51 ·
The YZ exhaust will be a larger diameter. I don't know if it would be worth the money unless you could exchange the system that you have for a YZ. My '06 had a WR header with a FMF 4.1 and it still hit plenty hard. You'd probably notice more mid to top end power with the larger system.
 
#54 ·
So i called fmf customer service today. The guy I talked to started to tell me that a Wr header would be better for supermoto application, because of the constant revvs that come with street riding. I then asked him to check the part numbers for an 03-04 YZ and WR(header and can), and he said that "it looks like they are the same now." Not sure if that means they used to be different, or he just didnt know they were the same :headscrat As soon as i hung up the phone i realized that i should have asked about other model years for yall :damn: Here is the number I called If you have a question. (302) 631-4363 Didn't wait on hold at all
 
#55 ·
Another simple and cost effective modification is a TRX450R master cylinder. The cost for the m/c was $30 on eBay and came with a electric brake switch and the lever and m/c were very close to the WR set up. I did need a little shorter banjo bolt, but other than that, this master cylinder was a very straight forward install.



Since it has an electrical brake switch, I also installed a R6 start/stop switch which has the m/c brake connections as well. Overall it gives a factory look and cleans up the bars, not to mention a much more solid feeling brake! The wires from the R6 switch will fit the WR plugs for a plug and play install.



 
#288 ·
Hey Crash, I recently got the R6 switch and a lever from a yfz450 quad. Lever is pretty long but I can take care of that with aftermarket or just put my WR lever on it hopefully. Anyway, I was wondering if maybe you could post up a little info on how you wired the R6 switch and the brake switch. I already have a RYCO on/off/start switch, but it doesn't seem to have the brake switch wiring. Think there is anyway to modify the RYCO switch to get the brake switch wiring to work on that one. Isn't the RYCO just a modified R6 switch? Also, I remember reading that with the R6 switch on/off positions are reversed,and it would be nice to use the RYCO and have the correct ON/OFF positions. I can't seem to find the thread again.

Thanks,
Zach
 
#56 ·
So I finally got to ride this bike after getting a fractured ankle healed up. All that I can say is that this is hands down one of the best bikes that I have ever owned! It handles on rails and is so predictable and confidence inspiring. The other surprising aspect was the engine. It's unbelievable how much difference a cam makes, but compared to my other '09 (with a Hotcam) this one has tons more low end grunt. Even with the 14/42 gearing it had power to spare but yet was manageable. This bike couldn't have turned out any better!
 
#61 · (Edited)
For those of you that want to retain the stock speedometer while running 17's, here's a quick and easy Speedo Healer Install:



The Speedo Healer harness simply plugs in-line with the speedometer cable (disregard the red wire coming un-pinned :lol:):





and that's pretty much it:



I attached the S/H box to my speedometer which is neatly tucked away behind the headlight (I'm going to cut the TSM harness and shorten it to get rid of the wire mess):



To calibrate this assembly you will need to get your "actual speed" as well as your "indicated" speed and plug those numbers into the calculator here (click on the speedo healer link and then the online calculator): http://www.healtech-electronics.com/

or you can download the app on your smartphone. Doesn't get any easier than this.
 
#62 ·
going to pick up a brand new left over 2010 in a few weeks and start my conversion. What restrictions make the most difference when removed? Im not sure if i wil have the time to remove the carb before riding it so i think i wil removed the stock throttle stop and removed airbox restrictions and AIS stuff. Are these the three main things to remove when derestricting? i wil then pull the carb and drop it that needle you recommend aswell as the R&d bowl but dont know when i wil have time for the last few things. just tryna figure out the most simple/significant restrictions and in what order i should go about sorting them..... exhaust will come at a later that also...
 
#63 ·
You're going to have to pull the carb to get to the throttle stop. I can still remember the fit I threw when I was working at Yamaha and had to de-restrict the first AF WR :lol:. The airbox mod and removing the pea shooter from the exhaust are quick and easy. The AIS removal is where you'll need the GYTR kit. I would go ahead and get the stuff for the carb if you can so that when you pull it you will only be doing it once...hopefully :D. The FCR carb, which is on every MX style bike, is notorious for bogging even in stock trim. I wouldn't get the R&D bowl though. I have found it better to just get the adjustable leak jet and it comes with everything you need. The R&D bowl doesn't have a drain screw so you can't easily drain the float bowl. Plus just buying the leak jet will save you over $100. Keep an eye out on eBay. A full YZ exhaust will work just as good as an aftermarket one. I found a brand new never used stock YZ system for a little more than $100.

If you're looking to ride it and not put any money into parts, I would cut the throttle stop down and remove the airbox snorkel and the exhaust baffle.
 
#64 ·
The Speedo Healers are amazing. Im running it on both of my street bikes because of gearing change and they very easy to install and calibrate. And supposedly they are more accurate to your speed then with the stock setup.
 
#65 ·
thanks crash just what i needed to know ive ordered the AIS removal kit now. So just the jd jet kit for the needle and the leak jet and i think thats it? do you think a 165 main jet is a good size to drop in at first. I know very little about carb tuning so my plan is to drop in the needle, leak jet and 165 in, then if it seems to run ok i will leave it like that until i can get it setup on a dyno...
thanks again for al your help
 
#66 · (Edited)
#69 ·
Okay, you'll need the blue needle for sure. Does the WR still come restricted over there in the UK? I thought that it was just something that they did to the ones over here in the states.

and unfortunately they won't ship to the UK! I will see if i can find a distributor over here!
eBay is the only place that I have been able to find that particular leak jet. It usually comes on the Powerbowl 2 which is a $270+ piece. You really only need the leak jet though and since it comes with the spring you can put your money to better use elsewhere.

Like I said: The JD kit and the leak jet will transform your carb into a monster.
 
#73 ·
Just had a look on the myus web site. Still not too sure how it works? Is it that they will ship items to you from the States from company's which will not ship outside of the USA? Does that make sense? Do you still have to pay the import tax that our Government kills us with?
 
#79 ·
Anytime...good luck to ya'.


Wow what a great sticky crash! Thx for putting in the time! Just got a 07 450 that's already street legal, gotta fin dme some 17's and sell my 250x lol. Great bike, but there is no replacement for displacement.
Let me know if you have any questions. The aluminum frame bikes are simply amazing once they're dialed in.
 
#78 ·
Wow what a great sticky crash! Thx for putting in the time! Just got a 07 450 that's already street legal, gotta fin dme some 17's and sell my 250x lol. Great bike, but there is no replacement for displacement.
 
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