Where is the Fuel Mixture Screw?

OK newbie question. Just got an 06 WR450. Doing all of the free mods. I got a ZypTy fuel screw but where does it go? Is there a plug I have to pull out? I have the manual but it doesn't show it. What am I missing, well besides the 48 main jet I forgot to pick up. Thanks for all of the help.


I have the manual on pdf it is 5TJ-28199-10. I think that is the same manual as per the sticky. It is on page 323 of 340. :devil:

The fuel screw SHOULD be towards the front/bottom section of your carb if Y the EPA wouldn't have forced a bogus design compromise. There is a small plug that blocks off the mounting hole for the fuel mixture screw that can easily be removed. There is a very small hole in the cap and I simply used a dental pick that I got at the hardware store to insert in the small hole. This cap will pull out pretty easily and your ready to install your new fuel mixture screw. It is a pain in the arse to get to the carb, but the results are worth it. Try looking at www.thumperfaq.com. I haven't been there in quite awhile but it used to have tons of info on free mods for the WR. Also, get a small adjustable mirror from the auto parts store or the hardware store. It's invaluable when working on the WR's carb. Wecome to the WR thread.

Take care when removing and installing the screws that you don't loose the spring, washer and o-ring :devil:

Take care when removing and installing the screws that you don't loose the spring, washer and o-ring :devil:

I forgot to mention that, I lost mine when I put my FMS in but the local dealer was nice enough to give me a freebie. The kid behing the parts counter could't figure out how to look up a price, so he just gave it to me.

Thanks all I got it. Now all I have to do is find a 48 tomorrow and I will be in business. One last question (yeah right) the Zyp-Ty is numbered. If you use something as a reference point and the screw is on #1 and I say need to turn it out 2 turns do I go by the next number, #2 or do a full turn back to the same number, #1? Does that make sense? Thanks


look in the thumpertalk technical sections for a good write up on rejetting your carb and removing your AIS.

A turn is a "full" turn, 1 to 1. Sounds like you're over-thinking things. Go to bed, you've got a busy day tomorrow thinking up new and wonderful things to spend money on for your new toy...SC

The numbers are there for your reference, once you screw it in fully, not overtight though as it can strip or break, you look from the same location, say from the left hand side of the carb, you see what number is there, say it's a 2, then one full turn out will show 2 again, turn another turn, still see the 2, turn it 1/2 more turns and you will see a 4, get it? the numbers are for 1/2 turn increments.

Thanks guys. I think I got it all now. I was up for 22 hours :devil:. Now I can think straight. Today should be :thumbsdn:

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