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) ). 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.