WR troubles/questions

My dad bought a 09 wr450 last january new and it seemed to be running fine stock, definately fine for him at least. I felt it was a little lean but it would idle fine. Fast forward to today the thing will not idle without the choke, once you get the rpm's up it runs fine but as soon as you slow down it will just die. I had no problems jetting my 09 yz and adjusting the fuel screw but the WR is so crowded under the carb I cant even reach the fuel screw, and the manual doesnt even show that it has one like my yz manual.

He said I could go ahead and buy whatever I need to fix it so he can ride and I was planning on doing the ais kit, fuel screw, throttle stop, grey wire, snorkel removal, and maybe going up one pilot, main and clip position on the needle(if I can't fix it with the fuel screw). Basically Im just wondering if the sudden change in how the bike is running is due to bad stock jetting or something else. Also, is there anything I need to be looking out for thats dramatically different than my yz? It looks like im going to have to take off the carb to do any of this stuff because the wr has wires and hoses everywhere, the bike is already annoying me lol.

Has it been sitting? Could be a clogged pilot jet.


X2 on the clogged pilot. Also, You can't see the Fuel Screw because it is inside the float bowl. It is blocked off and the only way to adjust it is to remove the bowl and make your adjustment. There is a block where you would normally be able to access the fuel screw. You can punch it out and replace the stock fuel screw with an adjustable one. It is recommended, and there are many pics on this site showing how to do it. I say, replace gas, drain float, replace pilot, and try again. Also, let us know what Pilot is currently in there. If you are experiencing much colder temps lately, it is pretty common to go up a size on the pilot. I just changed mine in my 07 from a 45 to a 48, and it's running great. 30-40 degrees.

Im guessing a clogged pilot as well, he hasn't ridden the bike for 2 months. I'm used to the yz without all the hoses and wires in the way but is it possible to remove the bowl without taking sub frame and carb off? I might be able to rotate it but when I was looking at it today it didn't even look like I could get to the air boot to loosen it.

Here's the bad news. It is very difficult to work on the carb without removing it. And, to remove it you have to remove the seat, sub frame, and rear shock. That is the only way it will come out. You can get to the boot clamp it just takes a long allen wrench and some patience. You can remove the pilot jet and main jet by removing the float drain cap/bolt, but it is a pain in the A$$! Try that first, many guys on here do it that way. If you get frustrated trying to access the pilot through the float drain bolt hole, and decide to remove the carb, you don't have to completely disconnect all the wiring and completely remove the subframe, just undo the the lower subframe bolts, the rear two exhaust bolts, loosen the top subframe bolt, and lift the subframe up and out of the way with everything still connected. I just hook a rachet strap to a beam in my garage, attach it to a section of my subframe, and sinch it up and out of the way, then remove the rear shock. Might as well grease the linkage while you are at it. You can adjust the need clip position while the carb is on your bike. Just remove the tank, and the upper engine mount. You can then pull the top of the carb off and make all your adjustments as necessary.

Edited by mikewrf18


Yea I figured Id have to do that, after all the work ive done on my yz I can get the subframe and shock off and on in no time. But thats a great idea with lifting it tho, I totally forgot that the wr has the coolant tank too.


Yea I figured Id have to do that, after all the work ive done on my yz I can get the subframe and shock off and on in no time. But thats a great idea with lifting it tho, I totally forgot that the wr has the coolant tank too.

Yeah, my yzf subframe is a sinch, no battery and wiring do deal with. You won't have to remove the coolant tank either. Just leave it connected, and pay close attention that you don't lift it too high without enough slack in your overflow tube.

I pulled the pilot on my 08... loosen the front and rear boot clamps.. remove the hot start lever from the top of the carb.. (its the black plastic one.. be careful, they can crossthread easily)

There is a vent hose below the carb.. I removed that as well as it was in the way.. once the clamps are loose, you can rotate the carb maybe 20-30degrees.. its enough to get to the bottom access bolt.

With a steady hand and a small screwdriver, it is possible to get the pilot out..

My bike had exact same symptoms as this a few months ago.. pulled pilot and sure enough,, goo.. cleaned and replaced and bike was as good as gold. Whilst I was at it, I also was able to install an aftermarket fuel screw.. again its tight but possible without carb removal!


I always try to remember to turn the fuel off and run the carb dry at the end of each ride.

I don't want fuel sitting in the float bowl and jets and stuff going gooey.

My bike often sits for months without being ridden, unfortunately.

It won't help if there's a bit of crap blocking a jet, but at least it helps reduce the chances of jets being clogged by old fuel gumming up.


sounds like a pilot problem

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