2004 WR450f Trouble shoot

I need some help here to see where to start on my trouble shoot. Not sure if I have a couple of problems with one solution. I am leaning towards the stator being the issue.

When I got the bike the headlight (stock) worked but over time it began to dim at idle and get brighter with RPM then it quit working all together. Now when you rev it up it backfires/bogs at the higher RPM. The electric start does not work now either. Kickstarts fine but the backfire issue worries me. And the starting indicator light does not even come on.

New battery in June.

Is it a stator not putting out enough voltage to get proper spark? Or is there somewhere else in the system I need to look. I have a manual so I was going to start going down the line. :thumbsup:


try a new battery again and keep a tender on it. If you are revving it on a stand and not on the trail the backfiring is irelivent . Have you done the free mods, like the gray wire mod in the above faqs? We will also need your jetting and elevation.

Looking at the mods on the board here and comparing them to the bike I see that the grey wire is cut. Need to look into the rest of the mods though. The bike is ridden often but I will check the battery.

The backfiring is happening while it is being ridden as well. My thoughts on an electrical issue is the start button red light does not even come on and it won't even turn the starter. I was just thinking maybe the stator (due to the ever dimming now dead headlight) was slowly dying and is now not creating enough spark to properly fire the motor at higher RPM's. I guess that could also not be charging the battery. :thumbsup:

Not sure what jetting is in there. My elevation is usually between 4,500 to 6,000 feet

Check all connections of battery cables (Battery, relay, etc...) make sure nothing is loose or corroded. :thumbsup:

I had a very similar problem on my old WR 426 and it turned out to be the CDI box. If you know another guy that would lend you his CDI to try out , you may either find or eliminate that as the problem, and do check all the connections and the exhaust connections too. :thumbsup: WR Dave

i had a very similar problem. my CDI was shot. try to find someone with a CDI for your bike and try a swap.

Thanks for all the info. I actually found the problem. I blew one of the fuses located under the seat. After I replaced that I started going over my wiring and found where my boots were rubbing on the wires that come from the rear brake cylinder. So I covered and re-routed the bare wire and problem it appears is solved. :thumbsup:

Now it is on to valve adjustments.

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