HELP 04 wr450 wont idle, runs hot ?

Hi guys i have a 04 wr450 im having trouble with it will not idle and seems to be running lean low to mid. here is what i have done so far. valves adjusted per service manual , gray wire mod, snorkel removed, stock exhuast w/ pmb insert, new main 160 and new pilot 48, bike was sitting for about a year. completely cleaned carb twice, new fuel. bike has low hours. I have tried 150- 170 main and 42,45 & 48 pilots with air screw from 1.5 - 3 turns with no luck. I adjusted idle screw all the way in but seems to only have effect when choke is on. I own a 03 wr450 that i modded myself that runs excellent. I told a friend i could help him with his 04 but i am about ready to start switching parts to see if i can get his going. Im at about 5000 ft elevation. I used the jetting that worked well on mine with this same setup hoping it would be close but i cant get it to idle.

I'm guessing you've got still some debris in the carb. One grain of sand in the mid body can cause all the issues you're describing. Also check and make sure your float height is proper

Edited by rs25

Your hot-start cable isn't hanging open slightly is it? This will definately cause your issues.


I checked the float level, checked for any debris blowing out all passages i could find, the hot start does not seem adjusted tight some slack on the lever. any other words from the wise?

i will keep you posted on the progress. I am going to swap my 03 carb in to see what happens. thanks

There is also a 3rd jet.. a starter jet that must be cleaned.. make sure it and its circuit is also clean..

is that the one next to the main? I will check it again. I also cleaned the jet in the air filter side of the carb and the leak jet

Yes its recessed up inside next to it.

on the left side of the carb if ur sitting on bike. there is a cover with two screws there is a diaphram, and an o ring turn the diaphram around, get a hole punch and an inner tube the hole punch part of inner tube will replace and block off hole where o ring is. could be wrong but im thinkin this is apu did this to my 03 wr 450 it is easy and reversible.

Edited by opiejrt15

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now