wr450 conversion


12 replies to this topic
  • wreckless711

Posted February 07, 2009 - 10:01 PM

#1

i want to convert my 450wr into pretty much a yz... i'm gunna cut the grey wire, and change the throttle stop, and get a stainless steel full exauhst kit from big gun, but i dont know what to do for intake, re jetting, and if there was anything else to help performance... please HELP!!

  • JSanfilippo

Posted February 07, 2009 - 10:27 PM

#2

What year is your bike?
Intake: Remove snorkle from airbox. Cut holes
Jets: Whats your elevation? Use the jetting database in the performace index sticky at the top of the page to get a baseline.
Airfilter: Stock is ok, but the twin air is superior IMO.
Disable/remove AIS (depending on the year)

In addition to the pipe (that you said you're planning on adding) the above mods are plenty for most. If you're sick in the head and/or in awe after riding a YZ (raises hand) you'll need to do this to get YZ type response...

-You'll need a YZ exhaust cam (and intake depending on the year of your WR).
-An aftermarket igniton (combined with the cams) will get rid that mellow initial delivery (about the first 1/8th of throttle travel)

  • erickdj

Posted February 07, 2009 - 11:58 PM

#3

If you're sick in the head


(ErickDj raises his hand..) :lol: :) :lol:

  • wreckless711

Posted February 09, 2009 - 07:53 AM

#4

well i believe its an 05 or 06? (raises hand) ive never actually ridden a yz, but i want to make it as fast as humanly possible!! and with the new exaust and intake, will the jetting need to be different because of that in addition with the elevation? i love riding, but dont know much about the mechanics of it... THANKS FOR YOUR HELP!!

i found out my elevation is 1,111 feet, but i cant find the specs for rejetting... also, what is the AIS?

  • JSanfilippo

Posted February 09, 2009 - 12:20 PM

#5

well i believe its an 05 or 06? (raises hand) ive never actually ridden a yz, but i want to make it as fast as humanly possible!! and with the new exaust and intake, will the jetting need to be different because of that in addition with the elevation? i love riding, but dont know much about the mechanics of it... THANKS FOR YOUR HELP!!

i found out my elevation is 1,111 feet, but i cant find the specs for rejetting... also, what is the AIS?


OK great.:)

Anytime you alter the airflow coming in or going out of the engine, the fuel mix must be richened to compensate. Jetting is also temperature and altitude sensitive but for what its worth the jetting in my bike works well from sea level to 7000 ft and from 40F to about 90F.

At 1,111 feet a 168 or 170 main and a 48 pilot jet would be a good starting point (with pipe and airbox mods). Fine tuning from there would require a new needle, an adjustable fuel screw, and accelerator pump tuning. The stock needle in the '05/'06 bike is garbage because its a fixed position needle. The YZ needle from an '03-'05 bikes would be a good replacement. The JD jetting kit gives you pretty much everything you need.

The '05/'06 bikes only need the YZ exhaust cam...the one from the '03 is the hardest hitting one.

The '05/'06 bikes do have an AIS. If you look at the right side frame tube behind the kickstarter there will be an airvalve with three tubes coming out of it (one from the airbox, two going into the head). GTYR has a block off kit which also has a YZ throttle stop, YZ needle, and main jet.

  • 123BigcoopDawg576

Posted February 09, 2009 - 12:36 PM

#6

The '05/'06 bikes do have an AIS.


JSan
My 06 "use to have" the AIS :lol: :) :lol:

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • wreckless711

Posted February 10, 2009 - 08:10 AM

#7

so my list of stuff to do to make it faster is remove my snorkle, cut some holes in the airbox, put on the full kit from big gun, rejet my carb to 168 or 170, maybe get a new exaust cam (probably wont), in addition to cutting the grey wire and changing the throttle stop. am i missing anything?

  • erickdj

Posted February 10, 2009 - 09:46 AM

#8

so my list of stuff to do to make it faster is remove my snorkle, cut some holes in the airbox, put on the full kit from big gun, rejet my carb to 168 or 170, maybe get a new exaust cam (probably wont), in addition to cutting the grey wire and changing the throttle stop. am i missing anything?


you pretty much got it there. that stuff will make the bike really fast. At that point you gotta start thinking about suspension mods/upgrades, the stock suspension is not too good when pushed hard.

  • wreckless711

Posted February 10, 2009 - 12:10 PM

#9

what can i do to it besides stiffen it a little?

  • erickdj

Posted February 10, 2009 - 12:25 PM

#10

what can i do to it besides stiffen it a little?


you could change the oil, and put different springs. Anything beyond that is not worth the $ in my opinion. By the time you pay a shop to respring and revalve the forks you could buy a complete yz suspension with forks and rear shock. I did that for $500.

  • irishjedi

Posted February 11, 2009 - 04:16 PM

#11

I did this exact conversion on my 03 and even recently stuffed the motor into a YZ250f 2008 frame!

Before the frame conversion, I drilled 6 1" holes in the airbox and installed the Uni plugs to help breathe even more, installed a GYTR oval exhaust, did the accel pump cover, the gray wire, the YZ cams, the jetting, removed all lights and wiring for them,.....everything else that you already mentioned. I also swapped the WR suspension for YZ revalved stuff and in my opinion, it was better than any of the other changes on the track. The ONLY change I didn't make was the flywheel. The YZ one is much smaller and would make the bike hit faster, but I wasn't sure the YZ flywheel setup would be enough to charge the battery. Anyway, you're going to love it and there's nothing like picking up your bike, hitting the button and riding away!

  • MaxPower

Posted February 12, 2009 - 02:18 PM

#12

[COLOR="DarkGreen"]you wont realize how good that motor can run until you install the YZ cam[/COLOR]

  • 123BigcoopDawg576

Posted February 12, 2009 - 02:34 PM

#13

I did this exact conversion on my 03 and even recently stuffed the motor into a YZ250f 2008 frame!


can we see some pictures of this?




 
x

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.