NEW '09 WR450f. were this jet fits?

In the USA, the WR-450F (and the WR-250F, which I own) roll off the showrooms corked-up with airbox intake restrictions (snorkels), lean carb jetting, and a totally plugged-up exhaust.

The bikes are very quiet, but run well below their potential.

I can't say exactly how the WR-450F runs off the showroom, but my 2009 WR-250FY was whisper quiet but comical in the throttle response and power output departments. :banana:

In the USA, the bikes come like this to pass rediculous EPA regulations, and this GYT-R AIS removal kit is sold by Yamaha Motor Corp., USA as an option.

It comes with carb jets and needle, a shorter throttle stop to allow full throttle, parts to remove the AIS, and instructions showing how to install these items, as well as perform all of the other "free mods" the USA WRs need to make them run like you'd expect from a 21st century dirt bike.

thanks, already did that.

but, for what i'm reading in all of your posts from you guys on the other side of the pond, is that you talk about a GYT KIT?, do you have to buy the jets to put the WR running good out off the box?

this WR came along whit manual, spark plug wrench, carb needle puller, carb needle, and all other jets to change, including this damn main air jet. doesn't yours in the U.S. do?

the jets came in tiny plastic bags, rumbling around, inside the bike's spares box. there is no instructions on how to remove the AIS, or, how to install the jets. the only thing I had was the bike's manual (whit no reference to the main air jet and location, besides it's stock size in the manual index).

so, no GYT instructions eider, I search in the furum FAQ's, which confirmed where every other jet fited, but not the main air jet.

here in california we have to buy the kit separate included instructions whith photos, they make it easy to do the change over good luck

The Canadian / Euro versions of the WR's come with all those extra jets etc. in the service manual bag. My southern friends have to buy the GYTR kit from Yamaha or something else from someone else to get the bikes running to their potential. I believe that you are looking for this tagged picture. WR_Dave

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Sheesh - I was wondering where the extra jets came from. I just picked up an 08 WR450F (almost new, 165 km) and had a baggie with some jets in it - I didn't know what that one was for either - even after perusing this forum.

I installed the jets provided:

main 175

Pilot 50

leak 45

needle GDDSQ middle position

did free mods:

snorkle out

baffle out

grey wire disconnected

yz throttle stop

Have only tested a bit - lacks mid range power and misses at the top end

Also, fuel mileage seems pretty bad (8 L / 110 km)

I think it is too rich - I am going to play with needle clip position to liven up the mid-range. I have ordered an AIS removal kit from Applied Racing.

Now I know what that jet is for - thanks for posting.

Johnny

Sheesh - I was wondering where the extra jets came from. I just picked up an 08 WR450F (almost new, 165 km) and had a baggie with some jets in it - I didn't know what that one was for either - even after perusing this forum.

I installed the jets provided:

main 175

Pilot 50

leak 45

needle GDDSQ middle position

did free mods:

snorkle out

baffle out

grey wire disconnected

yz throttle stop

Have only tested a bit - lacks mid range power and misses at the top end

Also, fuel mileage seems pretty bad (8 L / 110 km)

I think it is too rich - I am going to play with needle clip position to liven up the mid-range. I have ordered an AIS removal kit from Applied Racing.

Now I know what that jet is for - thanks for posting.

Johnny

Hey Johhny, just because those jets are there doesn't mean they are right for you. I would say your whole combo in the jetting is waaaaayy too rich. I'm assuming that you are hitting some sort of mountain terrain in BC and those jets are more suited to sea level operation. Send a PM to TT member TribalBC and he should be able to help with the jetting that will get your bike ripping. Off tha top I would go to the 40 or 42 pilot jet, 165 main jet and I have had great success with the previous years YZ needle in the 3rd from the top position here in Albertas mountain trails. Also in an effort to keep from richening the bike any more I didn't use the main air jet either and my bike is very responsive and doesn't ping or overheat like a too lean engine would. I have a brand new main air jet for the next guy when the time comes. JMHO -- WR Dave

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