2005 WR 450 Help

A friend of mine has a 05 WR 450 that will start and run with the choke on, but as soon as you close the choke the bike quits. The bike is stock with the exception of a FMF Factory 4 Slip on. The carb is different than i am used to. There is no fuel screw and from what i have been able to read has something called a starter jet? I checked the needle, it is on the 4th notch. Main seems to be real lean with a 150. From what i have read, should be a 165. I could use some help from those of you that may be able to help. The bike has had none of the mods done.

no mixture screw?

i would check out the parts diagrams here:


if there is no fuel screw, then i'd get an aftermarket one. then pull the main and pilot jets. see what they are, then set them to what is recommended for your altitude.

most guys from 0-4000 ft will run a 165 or 168 in the main, and a 45 or 48 in the pilot. the starter and leak jets are in different places, but i'd worry about the screw, pilot, and main first.

make sure the carb is clean too.

good luck, and keep posting after you make some changes.

There is no fuel screw on this carb. It is not like the reguler FCR carb. The casting were the fuel screw would go is there, but there is a metal plug in the hole? If you look at the parts diagram, it does not show the fuel screw. I know the main jet is to lean, but this should have no effect on the bike ideling.

The WR carb comes with a plug over the fuel screw. I have no idea why.....

you have to remove that to get access to it. you put a screw in the plug, then yank it out with pliers. The part number on the yamaha website is 5NL-14105-00-00 PILOT SCREW SET.

Check out the sticky at the top of the page.

I have the factory 4 slip on also. You really need to let that carb breath.

Look at the jetting guide, get the JD Jetting kit. Follow the instructions, very carefuly.

That bike will run perfectly.

kskyles, I may be wrong but the fuel screw and the pilot are to two different circuits. The pilot sits above and inside the float bowl. The fuel screw sits in front and outside the float bowl. The fuel screw is adjustable and the pilot changes through different sized jets.

There is a plug over where the fuel screw sits. It is put there from the factory for the same reason the AIS system is. Theres a pic of it in some thread I found I'll provide a link when I find it.

Found the link.

Link here

Thank you, that answers my question!!

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