Over Heating Wr450 2005

My WR over heats frequently. I go through an 80 mile desert race my overflow reservoir will be at the correct level. After the race the reservoir will be empty and the radiator will be 1/4 low. I understand if the terrain is technical and the bike isn't moving fast enough to cool it but it over heats too easily. My other friends with WR's don't have the problem i do. I have only done the grey wire, baffle out, and air box mods. Everything else is stock. Any help appreciated! Can this have anything to do with jetting?

You're probably running too lean and the bikes running too hot. What's your elevation and what jets are you running?...SC

You're probably running too lean and the bikes running too hot.

Thats what I think is the problem also.

Too Lean!!!! By opening up the bike even the amount you did you will lean it out. Re-Jet and it will be fine.

I have rode my WR in a wide variety of Arizona heat. This thing has never overheated. The only time I've come close was at Glamis after I realized I still had my 160 main in from riding at 6500 feet weeks earlier. I also agree that you may be too lean. These bikes run even if jetting is way off.

Good luck

I agree it is lean, I used to have the same problem until I got the jetting right then haven't overheated since. Richen it up and it probably won't overheat again. Look at the jetting database and start from there.

lean cuisine

richen it up and it will run cooler.

I had the same problem on my 05' until I rejetted. The hot Texas summer and slow riding in the woods would overheat once or twice a ride until the change.

Model (400 - 426 - 450): 2005 450

Timing (WR-YZ): WR

Main jet: 168

Pilot Jet: 48

Fuel screw (turns out): ZipTy - 2 turns

Needle model/Clip position: Stock

Airbox lid (on or off): Snorkel out, punch-outs removed

Pipe: Stock, baffle removed

Altitude where you ride: 100 to 1500 FT

Temperature where you ride: 55F - 75F

I would like to also suggest that you get the PMB exhaust insert also to help it breathe and let some heat out. The pea shooter exhaust just doesn't get it. Do the throttle stop also and let-er rip.

BTW Jetting is easy....Don't let it scare you, JD comes with all the instructions you'll need, Here is some more just in case.


I did not find it necessary to remove the entire float bowl to replace the main jet... just the big plug screw in the bottom of the carb.

my 2004 WR450 runs so cool after about 15 minutes after riding it, I have to use the choke to get it started again cause of it cooling down so quickly

Since you losing fluid, you must have a leak, replace your radiator cap.

Thanks for all of the help guys i will get that jd jet kit and take care of this problem.

Then fix the problem and replace your rad cap :thumbsup:

Question guys. I have an 06 wr450 and I only h ave about 116 miles on the odometer. Last time I went to go ride I hit my friend with my left radiator. I kept riding and everything felt fine but tonight, after I rode my bike and was parking it in my gaarage, I noticed a little bit of smoke rising from the radiator area. When backing up the bike to reposition it, a little bit of smoke rises into the headlight area and thats how I know that it is kind of smoking. Is it just because the radiator is hot or is my radiator damaged? thanks.

The same thing happened to my 04 when it was new. The problem was the rubber boot connecting the carb to the motor, and also the one connecting it to the airbox. The factory didn't tighten the clamps enough, so the engine was sucking in outside air, as well as from the airbox. I had to remove the metal cylinders on the bolts to make it even more tight, but ever since then it has been perfect. Try that out...

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