Tell me which mods

5 replies to this topic
  • Mrlieu

Posted June 28, 2006 - 01:19 AM


I'm confused, too many posts, too many jet sizes, jd, bk, it all starts to blend into one big

I live in Victoria Australia, and i own a 01 WR426. i want to know what i can do to it to make it a lethal machine. it is all stock except the pipe, which is a Barretts.

Should i do the yz cam & timing thing ?
What sizes should the jets be ?
Should i get a kit for the carby ?
What octane fuel should i be using ?

  • simon@vic

Posted June 28, 2006 - 07:45 AM


-yz timing is nice if you are riding all open terrain! {i put my WR cam back in}

-jets depend on the temp and elevating where you live

-yes, buy a JD jet kit

-is AUS you need to run 95 oct!

  • bluebike1999

Posted June 28, 2006 - 02:49 PM


as i understand, the 426 can have the yz timing without replacing the cam,
i have done that mod on my 400 and love it, although the true benefit of a wr is not to spin but to grip, for which the yz style power will tend to spin sooner.
why complicate things with a jd jet kit when you can get what you need from your local yamaha stealer and stay original and genuine?

open up the airbox, it'll sound faster.
many will say that $ are better spent in suspension land.
unless you find that your 426 is underpowered( i always thought the 426 was an animal already) why comprimise reliability and overall ground speed for the sake of winning the occaisional drag.?

hope that helps

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  • Mrlieu

Posted June 29, 2006 - 12:35 AM


I want to do something about the bog it has when giving it a hand full. Does the JD kit eliminate this ?

Are these kits easy to install ?

If i do the YZ timing thing, could i maybe gear it differently to compensate ? - say a 48/14 ?

  • GCannon

Posted June 29, 2006 - 02:30 PM


The BK mod is for your carb and yes done carefully it will reduce/eliminate the bog. you will need to increase the main jet after doing the BK mod. you may want to use INDY'S jetting chart as a guide. I belive (but am not sure) that the canadian(which I have) and the AUS WR's are the same so the carb may have a YZ throttle stop in it already(confirm by looking in the carb and see if the slide opens fully in the throttle bore) the needle is also richer than the US needle making the JD kit more optional. You already have a pipe which makes the big difference. then go ride

  • temptation2003

Posted June 29, 2006 - 06:50 PM


Buy a JD jet kit!!! PERIOD I was also wondering if it would help, before my bike wouldn't want to start at 40degrees farenheight and when it did would take forever to warm up but after putting on a new fmf pipe and JD jet kit ( I installed both myself pretty easy, you can find good info on installing jets on the internet just look around. as far as setting for elevation and temp use indys jetting database and find someone who runs about the same temp and elevations as you and try their settings that is what i did!) The bike now starts at 40 degrees without a problem and is ready to idle without choke in like 10 seconds after starting! I've ridden in weather as warm as 90 degrees and it still works perfect!! Also the power from adding a JD Jetting kit and FMF exhaust seemed like alot more :ride:

My rating JD JET KIT :ride: :ride: TWO THUMBS WAY UP

Hope this helps a little...


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