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JeffWR

Pilot and leak jet replacement

10 posts in this topic

Are there any little tricks in replacing these 2 jets, i.e. little washers, o-rings etc. Does Yamaha call them the same name as you guys do on here? I have never replaced them before.

Thanks for your help, Jeff

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New with 05 WR450F (2 weeks)

Have the same question. :)

Also ¿ can I change the Jets without removing the CARB ?

¿ Are the Fuel & Air Screw in the same place as Jets ?

Marco

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Are there any little tricks in replacing these 2 jets, i.e. little washers, o-rings etc. Does Yamaha call them the same name as you guys do on here? I have never replaced them before.

Thanks for your help, Jeff

Here's my 2 cents: Loosen your subframe, take the top bolt out and then loosen your carb boots. Slide the intake boot off and twist the carb towards you. Remove the float bowl and change the jets. The only o-ring is the seal for the float bowl. The jets simply unscrew(very easy to change). While your there, put in a zip ty fuel screw-there is an o-ring on this when you pull out the oem. Mkae sure the little washer and o-ring go back on b4 U put the zip ty in your carb. Also change your needle to an adjustable type JD or an '04 WR needle. Install a 170 main, cinch her back up and pop some wheelies! :)

P.S. Yamaha calls the Pilot jet a "Slow" Jet

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Have two spare jets MJ #170 & #180 from my old '99 YZ400F, Can be used in my 05 WR450F ? :)

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If your bike is an '05 WR you won't be able to access the fuel mixture screw to replace it with a ZipTy or other aftermarket fuel mixture screw. The stock one is covered by a small aluminum cover which is easily removed with a dental pick. Buy a Motion Pro carb tool for the FCR carb and it makes changing the stock fuel screw relatively easy.

You don't need to remove the carb to service the jets, just remove the float bowl cover for the mj and pj, The fuel screw is just if front of the float bowl and it is on the front side of the carb

Go to www.thumperfaq.com

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Mkae sure the little washer and o-ring go back on b4 U put the zip ty in your carb. Also change your needle to an adjustable type JD or an '04 WR needle. Install a 170 main, cinch her back up and pop some wheelies! :)

P.S. Yamaha calls the Pilot jet a "Slow" Jet

Don't forget the spring!! The sequence is: spring, washer, then o-ring closest to tip...IIRC

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You do need to remove the carb to get at the fuel screw, otherwise the starter is in the way....I couldn't twist the carb far enough to clear it.

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Just loosen the carb boots and twist it toward you. You can actually access the mj and pj through the bowl drain. You only need to drop bowl if you are replacing the leak jet. If you need to get at the needle, you will probably need to remove the gas tank and seat.

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You can get to the needle without removing the seat and tank, it's a little tight but can be done with minimal cussing. If it's your first time try removing the seat and tank first just to be on the safe side. Takes a little more time but might prevent problems until you get more acquainted with the process.

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