08 wr450 Help with carb issues after cleaning

Kenny everything you mentioned i checked 5-6 times, and the jets are squeaky clean

Called JD jetting and explained my issues and he said it seemed like a fcr mid body issue, he sent me a set of mid body gaskets. Tore my carb apart tonight and look what i found, the gasket was partially blocking the fuel screw hole.... Heres a pic

1. Mid body apart

2. Mid body upper part showing rubber gasket clogging fuel screw hole

3. Up close view

4. With the proper oring





Edited by Mbiker_101

So i took the bike out for a spin on the street and it's still missing.... Should i focus on electrical now?

Bike was running great, jetted perfectly per this forum. Jd red needle, 4th clip down, 168 main, 45 pilot, 2 turns out

Long story short, Crashed and split my foot open with foot peg so bike was sitting for about 3 months and carb was gummed up due to crappy cali gas.

Cleaned carb in detail, put everything back together with new spark plug.... Starts great but has a small stutter down low like not getting enough gas. Checked tps voltage and .782 volts, so i tore the carb apart again thinking a missed something, checked everything and put back together and had to turn fuel screw out three turns to idle smooth and i still have the stutter. I even unplugged tps because i know that is a quick test.

I'm lost as to what to try next? Why do i have to turn three turns on fuel screw now, what happened? How do i get rid of the stutter?


Now you are saying it is 'missing' ?


I think you need to be more specific: rpm, throttle position, hot or cold, age of gas, etc

Don't know specific rpm but gues 3000-4000, seems to be worse when warm gas is brand new vp100 octane. Pulled the plug and it looks normal. Going to open up the side to check the stator cables.

Don't know specific rpm but gues 3000-4000, seems to be worse when warm gas is brand new vp100 octane. Pulled the plug and it looks normal. Going to open up the side to check the stator cables.


Have you tried unplugging your TPS?

That was one of the first things i tried but that was a month ago, with so many changes i need to recheck.

Finally fixed the issue!!!!! Bad fuel filter!!!! I replaced the fuel filter as one of my first steps in troubleshooting this issue with a brand new filter the same one as before..... The new filter was flowing just enough to feed the carb and flow looked pretty strong but not 100%. I thought couldn't be fuel filter because it,s brand new.... But bypassed the filter and flow seemed much better. Went for a quick ride and much better but not perfect. Once warmed up completly, I adjusted the fuel screw and to my surprise i'm back to two turns out and runs like a champ!!!

I spent a ton of time troubleshooting this issue and it turns out it was a simple fuel filter..... But the good news is i went through about every other system and made sure they're 100% so my carb is as good a new and running perfect!!!!

Thanks for all the help guys!!! This forum rocks

You made no mention of a fuel filter.


Probably one of those translucent plastic ones, huh. 


They SUCK...........

Yup, clear one, thought the original could be clogged so i replaced with a new one from cycle gear.... But the new one flowed terrible. Wish i would have just bypassed originally and that would have saved countless hours of troubleshooting.

The accelerator pump camoflaged the issue by providing a solid squirt of fuel and when the throttle was constant the fuel line couldn't feed the carb so is felt like it was running out of gas... Well it was... Slowly

Ok, so I drained the tank yesterday and removed the petcock to clean the tank and rotote the petcock so it faces the carb to shorten the gas line and remove the fuel filter so we get full gas flow.

Went to the local station that sells VP 100 to put fresh gas in for the thanksgiving weekend in the desert.... Well, went for a test ride to make sure bike is 100% and the stumble and rough running is back???? Do you think it was bad gas even tho it was brand new? My thought is since this is 8.99 a gallon it doesn't get rotated often and is bad? Called the station and the owner swears it was new two weeks ago?

Is he full of it and it is bad gas or something different with 100 octane? I'm going to drain the tank and put regular gas in to test but i'm wondering if this was the issue all along?

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