2006 Yamaha WR 450f Performance Mods?

ok folks...Need some advice. The Yamaha AIS removal kit is on Back order till late Dec. This said, I was able to muster a 170/168 main jet, 48 pliot jet, but can't get a starter or leak jet. Can I add the 168 main jet and 48 pilot without changing the other jets?

Also, here's the mod's done thus far - opened the air box, added an easy to access fuel screw, have a YZ throttle stop, pulled the grey wire and I'll be putting in a PMB insert later today (waiting for it to arrive).

The bike is still not broken in and I was hoping to have everything all set for this weekend. Since I don't have all the jets and an adjustable needle, should I still add the main jet and pilot or leave them stock for now and leave the modes llisted above "as" is for now?


Go ahead and replace the main and pilot and ride the thing. I think it was mentioned before about shimming the needle with a couple of small washers which would be a good stop-gap until the adjustable needle arrives. As far as the leak jet goes, you won't notice it unless your wicking open the throttle at or near idle. Just do mellow, even roll-ons and you'll be fine. Besides, you're breaking the bike in so you shouldn't be jack-rabbitting anyway. Make sure you change your oil and filter after you have about 25 miles on the bike. I know it sounds extreme, but you just dropped a ton of cash on the thing and you'll be amazed at the amount of crap that comes out with the oil. Contrary to popular belief, bits of aluminum and steel are not good lubricants :applause:. Now I'm also a firm believer in running oil that is totally non-synthetic until the bike has at least 500 miles on it to get things to seat properly. This is an often argued opinion, but it's how I've always done things and I've yet to have a vehicle that burns even a drop of oil. With that said, I change my oil before I even started break in, but most people on this forum think I'm a nutjob :ride:...SC

just took it for a spin after performing the following:

1.) Removed the grey-wire (Free)

2.) Added an adjustable Fuel Screw (set at a full 2 turns out) ($20)

3.) Added a MJ 168 and 48 PJ (as recomended) (a few bucks)

4.) Added a YZ 450 throttle stop screw (a buck or two)

5.) Added a PMB exchaust insert ($59.95)

6.) Open the air box openings (Free)

In short, the bike started almost immediately to my delight. The stock bike was VERY difficult to start so this alone was impressive.

Took it for a spin to see if all the hype surrounding the "Performance Mods" was justified. OMH, this think hauls ass now. It feels like a different bike, just as everyone indicated. I am SO impressed and want to thank everyone for all their help on this topic. :applause:

It's such an improvement over stock, it's difficult to describe the transformation other than the stock bike just feels "choked.". The "NEW" bike feels like a race bike and pulls so strong in comparision and revs much better. I'm still in shock at the moment since the improvment is so profound. It now feels like the bike that I thought I was getting off the show-room.

If anyone has questions relating to anything that I've done or needs help (I'm now an instant expert) :ride: let me know.

Just need to do some suspension tweeking now.

Peace out!

...told ya :applause: Enjoy your new toy!

Just bought a 2006 WR450. I'm taking it out tommorrow in it's bone stock Fed up California emissions condition. :p After reading all this great info, I can't wait to get back to the dealer and order up that kit. Thanks for all the great tips> :applause::ride::p

I ride 75% at altitudes between 5,000-9,000 and the rest at 2,000ft. You think I should be ok with the stock jetting?

I bought the zip-ty mixture and will be installing that in a few days. I also have removed the AIS, throttle screw but not the grey wire.

I have not done anything with my airbox or exhaust as I want to keep my bike real quiet. I heard the pmb insert is a lot louder than stock.

Any suggestions???


Marco Polo

The 2,000Ft end of your riding range might be a little lean with the stock jetting, if it doesn't backfire on deceleration your OK. Remove the snorkle, cut the holes in the air box, REALLY consider rerouting the engine breather hose up to the now unused AIS fitting on the airbox (water in the air box will go into the top of the motor as currently configured), cut the end off of the air box drain hose and remove the inner small tube from the muffler, it opens the exhaust up nicely and is still quiet, "Less Sound = More Ground".

Went riding this past weekend and the bikes hauls ass!!!! So impressive and what an awesome bike now...

Thanks again for your assistance with performing my FREE mods!!!!

Yup! I remember my first ride without the bike having it's wings clipped!

Get a decent pipe and you can have that feeling all over again! :applause:

I'm not sure where you are in CA but I'm running the 45/165 with the AIS kit needle 4th clip, fuel screw @ 1 3/4 combo in my 06 and the bike kicks butt. I'm not ready to say it's perfect because it might need a 162 main.

The 48 was too rich because the bike would idle with the screw all the way in and felt fat. And with the 45 the bike is very crisp.

The 168 also felt blubbery and the 165 has added some quickness to the top end which is why I might try the 162.

BTW- Pipe tip, Power Now and Uni filter installed. And I ride everywhere and all year. :applause:

I'd like to try the JD red needle if anyone wants to sell one. (I don't need or want the rest of the kit) PM me if you do.


The PMB insert is virtually as quiet as stock for me. I can barely tell a difference in sound volume, but performance wise I noticed a big boost!

Okay, let me get this straight. The AIS kit comes with 48 Pilot Jet and 168 Main Jet. According to this thread, I should be somewhere in the ranges listed below for Northern California. I have ordered the PMB insert and AIS kit so far. What are the other things I need to order and where do I get them for the 2006 WR450F? I think I need the Fuel Screw and JD Kit from the TT store listed in these links:

Zip-Ty Fuel Screw

JD Jetting Kit JDY001

What else do I need and where do I get them? Also, let me know if that is not the right fuel screw. Does the JD Kit come with all of the jets I need? I am new to this so any help is really appreciated.

60 to 75 degrees: 168 main, JD Blue #3 or JD Red #5, 48 Pilot, 1.5 turns, 70 starter jet, #40 leak jet

75 to 90 degrees: 165 main, JD Red #5, 48 Pilot, 1.25 turns, 68 starter jet, #50 leak jet

90 degrees plus: 160 main, JD Red #4, 45 Pilot, 2.0 turns, 65 starter jet, #60 leak jet


I'm new to this as well... I went last weekend (Hollister, Nor-Cal) for the first time after installing the GYTR AIS removal kit and the ProMoto exhaust insert... the bike was incredible! That's all I'll do for quite a while... It's that impressive of a difference over box stock. My next few dollars will be spent on suspension tuning / upgrades and possibly a larger tank.

Here are the specs for the stock 2006 WR450F sold in California

Main Jet = 165

Pilot Jet = 45

Pilot Air Jet = 80

Starter Jet = 65

Leak Jet = 50

I have been reading all of the mods to be done to the WR450....and all I can say is WOW! I just bought an '06 last week and just breaking it in. I took it out in stock form the day after I bought it and was very disappointed in the performance. So I came home and did the free mods and made a big purchase also. The purchase included:

-Pro-Circuit T-4 full exhaust (no spark arrest)

-JD jet kit

-Zip-Ty fuel screw

-YZ throttle stop

-Assortment of pilot, leak, and starter jets

-NGK Iridium plug (CR8EIX)

A couple of hours getting the jetting just right this morning and :applause: see ya stock POS WR!

The bike is not even the same.....power, starting, and throttle response is unimaginable now. Thanks TT and everyone that has posted on this thread.

what did you have to do to change plugs? Do you need to remove the tank or other components to get to it?


what did you have to do to change plugs? Do you need to remove the tank or other components to get to it?


I take the tank off to get to the plug, I don't think you can get it out otherwise. Just 6 bolts anyway! 2 for seat, 2 for rad scoops (front bottom), 2 for tank. undo clip next to battery, pull off fuel hose, and tank comes off.

Just pull out the coil (plug lead) and get your bendy plug spanner and pull it out. Make sure it is free from crap down there before you pull the plug out. Some air to blow it out is good.

I had done most of the mods on my '05 WR450 and the bike ran well but last month I ordered a Boyesen accelerator pump cover and was amazed at the improvement even over the other mods. The bike pulls wheelies in every gear with throttle only. I have a Rekluse clutch so you can't pop the clutch to pull up the front. The guys who rode the bike the first day I was out were amazed. It's a very good investment. I run the bike with the JD kit, stock exhaust tip removed, etc. It flat out flies now.

Where can I get in the net, a, BOYESEN ACCELERATOR PUMP COVER ?

Can I find it at the TT Store ?


Here in Brazil I could not find it anyware !


05 WR 450 :cry:

Where can I get in the net, a, BOYESEN ACCELERATOR PUMP COVER ?

Can I find it at the TT Store ?


Here in Brazil I could not find it anyware !


05 WR 450 :cry:

Order it from Chaparral.com. I got it from them and it was about $90 with shipping and handling. I don't know what their international shipping policy is though. Type in Boyesen and it will come up.

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