Tutorial - YZ450F (06 & up) Electrical System For Lights

in order to put a WR crank into a '03-'05 YZ450, you have to use the WR ignition cover, flywheel, stator, AND crankcases. Might want to reconsider.

Hmm....perhaps I was assuming the swap was essentially the same as the 06+ swap requiring:

Ignition Cover



Clutch Arm




but not the cases themselves. Based on your comment it seems like the 03-05 swap is different?

Either way, I likely will not proceed. If there was any way to put the WR crank in now and still have the option to do the rest of the swap later, I would still consider it. But since it is an all or nothing proposition, I agree that it is not worth it (at least not now).

It's a cascade of sorts. The only flywheel that will fit the crank is the WR, which means you have to use the WR stator, which requires the WR left side crankcase cover, which won't fit the '03-'05 YZF.

It's a cascade of sorts. The only flywheel that will fit the crank is the WR, which means you have to use the WR stator, which requires the WR left side crankcase cover, which won't fit the '03-'05 YZF.

And the '03 WR crank/flywheel is different from the '04-'06 WR's.

But the '04-'09 YFZ (not R model) crank/fltwheel will swap with the '03-'06 WR stuff..............


Edited by 2grimjim

Thanks for all the info. I wondered why the thread was specific to 06+ bikes, now I know. At least I have a spare WR crank for the next person that entertains this swap. Will be happy to rebuild it first too.

Ok, a few of you have asked for an outline of how I wired my 07 450 for lights to make it street legal. So here it is - hope it's helpful. Please note - this is A way to do it, I'm not saying it's THE way to do it. I'l give you my reasons why I did things the way I did along the way.

First off, you'll need a different stator with a seperate circuit to power some or all of your lights. As we've discussed previously, there are a few ways to do this If money is no object, pick up a 07 WR450 crank, ignition cover, and stator. You will need to split your cases to install the WR crank. This setup will give you the most power output (watts) BY FAR - but the drawback is cost - you're looking at around $1000 with labor, or about $600 - $800 if you do all the labor yourself, including welding up the hole in the WR ignition cover where the starter would go.

That's a lot of money, and frankly way more hassle than I wanted to do, so I went with the cheaper option, which if we choose our components carefully, will be just fine.

So option 2 involves either having your stock stator rewound by Lake and Trail, or buying a replacement lighting stator from either Electrosport or Moose. I bought both, and they appear to be the exact unit. Expect to pay between $165 - $195 for a stator. I think Lake & Trail charges around $225 to rewind your stocker, if my memory is correct. (also - for our European brothers - there is a U.K. company making a stator for our bike: http://www.electrexworld.co.uk/erol.html#9354X0 )

Before we go any farther, when deciding between option 1 or 2, determine how much night riding you will be doing and how important a really strong headlight will be for you.

The WR stator option will give you 100+ watts to play with, even more if you go with a aftermarket Trail Tech flywheel with stronger magnets. This much wattage will alow you to run a 50+ watt headlight which will be WAY better at night that a 35 watt light. Rewinding the stock stator or buying the Moose/Electrosport stator will net you about 50 watts AC power or about 34-40 if you convert it to DC. (More on that later) 50 Watts is barely enough to run a 35 watt headlight and an LED tail light. Not very bright at night! But for me, I really don't plan on ever riding my bike at night, and on the rare occasion I might, all the roads i'd be on are lit - so no big deal. My headlight setup is primarily to pass inspection to get my plate. Depending on your needs, chose accordingly.

OK - here's a pic of the Moose stator in the stock YZ ignition cover. Note the 2 extra wires - A black wire which goes to the chassis ground, and a yellow wire which is the hot lead for your lights.


You will also need either a voltage regulator if you plan on running the system AC to keep the voltage from going past 12 volts and frying a light, or a regulator/rectifier to also convert the output from AC to DC. Electrosport has the regulators for about $20, and Trail Tech has the regulator/rectifiers. Halogen headlights and a Baja Designs LED tail light will both run fine on AC, so I left mine AC. With DC, you can run HID lights. You can also install a battery if you want. Only problem is that a rectifier will eat up available watts and leave you with only 35-40 watts - and that's cutting it real close when just the headlight needs 35. Now I know an LED tail light only needs 1 watt, but remember our 50 watt stator only puts out 50 watts at half to full throttle. When you're cruising on the freeway at 1/4 throttle, the output WILL be less! Now if you run an HID light from Trail Tech, it only uses 19 watts - but it's not DOT legal, so you need to think about that. A LED tail light is pretty much mandatory, as regular bulbs use about 20-25 watts themselves, and that coupled with the 35 watt headlight puts you over the capabilities of the system. This is why I say component choice is critical.

Again, I stuck with AC to have more available watts, and used a 35 watt headlight with a 1 watt LED tail light.

I also recomend using good waterproof connectors like Weathertight. I also use a waterproof mini fuse holder to hold a 5 watt fuse to protect the system. Here's a pic of those items:


Fuse holders here: http://www.bmotorsports.com/shop/product_info.php/cPath/150/products_id/506

Weathertight connectors here: http://www.shopatron.com/product/product_id=MSD8173/424.0

I mounted my regulator behind my front skidplate. The slots in the plate allow air to cool the regulator:


Here you can see the fuse holder and weathertight connector. I cut the yellow and black wires from the stator a few inches out to mount the connector and splice in the regulator:


Here's the wiring schematic i used for the headlight and tail light:


The brake light switch is a hydraulic unit I got from Forrest at Wheeling Cycle. It replaces the banjo bolt on your rear brake at the master cylinder. The headlight high/low beam switch / horn / signal cluster is sold by Trail Tech.

Now for turn signals and horn, I used battery powered units because I really don't have much power left, and I'm gonna take them off after i get my plate anyway. For signals, i used led units from K&S - only use 1 watt and are dot approved ($100 a pair though). For my horn, I used a "megahorn" which is a self contained 9 volt battery horn:


To power the turn signals, i just got a 8cell AA battery holder from Radio Shack. I used an LED specific flasher unit , also from Forrest at Wheeling. I just sat the battery pack in the airbox, along with the flasher.


(after I get my plate, all this mess of wiring will be sleeved and generally cleaned up)

That's pretty much it guys - a very basic system to get your YZ street legal with the bare minimum. I'm probably forgetting something here - just ask and I'll help with any more questions.

Awesome post. I want to put this out there I tried a electrosport and had two fail (they replaced them) and the last time they said that they didn't have an answer for the problem yet and wouldn't for a while i called them and inquired several times and they still hadn't figured it out so the last time dec 2010 i decided to do the wr swap, so i chose the wr set-up. I started out not know a lot about wiring and through a lot of people on here I learned and completed the project by myself. Thanks to those people and Grayrace.

That aside i picked up a frost plug for a car from advanced auto parts to plug that hole in the wr side cover. Pressed it in and no problems on the seals, I also went with a rick stator replacement stator and gained 120w and a great replacement and awesome customer service!!! If anyone has any questions about option A hit me up i Can help.

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