wr jetting question


18 replies to this topic
  • The Hopper Show

Posted March 25, 2011 - 06:27 PM

#1

so i found this old post by ARin when searching for jetting. I am doing the "free" mods to an '05. throttle stop/grey wire. remove baffle in insert or replace with pmb insert. possible air box mod and ais removal kit.

i am planned on buying the jd jetting kit to rejet the bike, but was wondering if i should also buy the boyesen quickshot accelerator pump cover, or if i would just be wasting money. does it really help and make a huge difference? or is it not noticable and a pointless mod? and should i get the zip tye fuel screw too?

also wanted to know where would be a good starting point for my jetting. i will be riding around portland oregon. anywhere from brown's camp, and then over to bend. i would say the average temp here is 70-75...up to 90+ in summer (but that is short lived), and prob wont ride much colder than 55-60 degreee weather. over around bend it is a higher elevation, and the temp is usually well over 80 and into the 90's for most the summer.

now, i know the bike will run richer the higher the elevation, but what does it do when the temp goes up? does it get leaner? if so, according to this post, where would be the best place to start? i am thinking this:

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

am i on the right track? should i make changes to those sizes?

the bike also has a small dent in the stock header close to where it exits the jug (from falling and smashing rock). will this hinder the bikes performance or throw off jetting?

thanks! :thumbsup:



AIS is air injection to help burn spent fuel to meet CA regs for trail bikes...it is un-needed. AIS removal is cheap and easy. Get the kit here at the TT store.
http://shop.thumpert...talk_aissrk.htm
OR yamaha OEM has a GYTR kit that does the same thing.

The throttle stop is long, open up the throttle body, and remove the stop, cut it to YZ specs, re-install. free mod.

Open up the airbox by removing the snorkel, and cutting open the right side. Im not sure if the 06 have the pre-scribed cutting areas.

find the grey wire and clip it or disconnect it. This will recurve the timing to meet the demands of full throttle.

Open up the exhaust in whatever manner is appropriate, remove baffle, aftermarket endcap, aftermarket slip on silencer, etc.

re-jet the bike using INDY450's jetting chart:
Elevation 0 to 4,000. feet

30 to 45 degrees: 172 main, JD Blue #5, 48 Pilot, 2.0 turns, 75 starter jet, #0 leak jet
45 to 60 degrees: 170 main, JD Blue #4, 48 Pilot, 1.75 turns, 72 starter jet, #0 leak jet
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

Elevation 4,000 to 8,000 feet:

30 to 45 degrees: 170 main, JD Blue #4, 48 Pilot, 1.75 turns, 72 starter jet, #0 leak jet
45 to 60 degrees: 168 main, JD Blue #3, 48 Pilot, 1.5 turns, 70 starter jet, #40 leak jet
60 to 75 degrees: 165 main, JD Red #5, 48 Pilot, 1.25 turns, 68 starter jet, #40 leak jet
75 to 90 degrees: 165 main, JD Red #5, 45 Pilot, 2.0 turns, 65 starter jet, #50 leak jet
90 degrees plus: 160 main, JD Red #4, 45 Pilot, 1.75 turns, 65 starter jet, #60 leak jet


Elevation 8,000 to 11,000 feet: ( Note you will loose a lot of power due to altitude but your bike will idle and not foul plugs!)

45 to 60 degrees: 165 main, JD Red #5, 48 Pilot, 1.25 turns, 70 starter jet, #40 leak jet
60 to 75 degrees: 160 main, JD Red #4 , 45 Pilot, 1.75 turns, 68 starter jet, #50 leak jet
75 to 90 degrees: 158 main, JD Red #3, 45 Pilot, 1.5 turns, 65 starter jet, #60 leak jet


and refer to my tutorial when jetting:
http://www.thumperta...ad.php?t=309069



  • Leardriver

Posted March 25, 2011 - 09:51 PM

#2

162 main, everything else stock. You don't need a JD kit, those bikes ran pretty good out of the crate.

A small dent in the header is ok. Big dent, not so good. No quick shot needed. Adjustable fuel screws are always nice, but if you set yours to 2 turns out, you'll be close enough to ride it for a while and see if you discover any driveability issues.

  • William1

Posted March 26, 2011 - 01:58 AM

#3

Do not get the ZipTy fuel screw. Get a Merge racing, James Dean, Kouba, Scotts or Kientech. These are all brass or stainless.

+2 on no QS2, carb jewelery. Buy your girlfriend dinner instead, you'll get more for your money. Or better still, send me your money, I'll be your friend.....

Get the Merge Racing AP spring. Check the AP setting by following the manual EXACTLY.

As far as jetting changes, never change the jetting unless there is a problem. Arbitrary changes are often the cause of major headaches.

  • The Hopper Show

Posted March 28, 2011 - 05:10 PM

#4

so you are saying after opening up the airbox and exhaust i will need no jetting changes? that makes zero sense. the bike will be getting alot more air. :thumbsup:

  • ARin

Posted March 28, 2011 - 08:10 PM

#5

follow that chart that you quoted.

you may need to fiddle with the fuel screw setting a bit to get it perfect...but that chart will put you DAMN close.

COOLER air will be more dense, and have more O2. Hotter air will be less dense.

0-3000 75-90 jetting works for MOST people as an all around. This is what i used in baja, with greatly varying temps and elevations. Worked very well.

these jetting changes arent arbitrary. They CORRECT what is normally a very lean factory condition, that only gets leaner with the more mods you do.

plug in the new jets, and post your findings.

almost forgot...I have also found that the 40 leak jet is pretty much the only one i use. keeping the LJ size small minimizes throttle bog.

  • The Hopper Show

Posted March 29, 2011 - 10:42 AM

#6

follow that chart that you quoted.

you may need to fiddle with the fuel screw setting a bit to get it perfect...but that chart will put you DAMN close.

COOLER air will be more dense, and have more O2. Hotter air will be less dense.

0-3000 75-90 jetting works for MOST people as an all around. This is what i used in baja, with greatly varying temps and elevations. Worked very well.

these jetting changes arent arbitrary. They CORRECT what is normally a very lean factory condition, that only gets leaner with the more mods you do.

plug in the new jets, and post your findings.

almost forgot...I have also found that the 40 leak jet is pretty much the only one i use. keeping the LJ size small minimizes throttle bog.

awesome man. so you are recommending this as the starting point then? or should i try a 40 leak jet?

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


and regarding air...you mentioned hotter is less dense. does less dense mean leaner?

  • ARin

Posted March 29, 2011 - 10:56 AM

#7

COLDER DENSER air causes a LEANer condition, necessitating richening the jetting.

Use this as a starting point. See how close that gets you.

165 main, JD Red #5, 48 Pilot, 1.25 turns, 68 starter jet, #40 leak jet

  • The Hopper Show

Posted April 01, 2011 - 08:14 PM

#8

hey arin do you think that will change much if i opt for a slip on exhaust instead of just opening up the factory can?

  • ARin

Posted April 02, 2011 - 12:43 PM

#9

hey arin do you think that will change much if i opt for a slip on exhaust instead of just opening up the factory can?


not a LOT...probably will just need to fiddle with the fuel screw

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  • jayde5411

Posted April 03, 2011 - 11:46 PM

#10

so i found this old post by ARin when searching for jetting. I am doing the "free" mods to an '05. throttle stop/grey wire. remove baffle in insert or replace with pmb insert. possible air box mod and ais removal kit.

i am planned on buying the jd jetting kit to rejet the bike, but was wondering if i should also buy the boyesen quickshot accelerator pump cover, or if i would just be wasting money. does it really help and make a huge difference? or is it not noticable and a pointless mod? and should i get the zip tye fuel screw too?

also wanted to know where would be a good starting point for my jetting. i will be riding around portland oregon. anywhere from brown's camp, and then over to bend. i would say the average temp here is 70-75...up to 90+ in summer (but that is short lived), and prob wont ride much colder than 55-60 degreee weather. over around bend it is a higher elevation, and the temp is usually well over 80 and into the 90's for most the summer.

now, i know the bike will run richer the higher the elevation, but what does it do when the temp goes up? does it get leaner? if so, according to this post, where would be the best place to start? i am thinking this:

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

am i on the right track? should i make changes to those sizes?

the bike also has a small dent in the stock header close to where it exits the jug (from falling and smashing rock). will this hinder the bikes performance or throw off jetting?

thanks! :cheers:


Run a 45 leak jet
45 pilot jet
162 main jet
NFPQ needle
Set the needle to clip 4

  • chiefster1976

Posted April 04, 2011 - 10:18 PM

#11

Run a 45 leak jet
45 pilot jet
162 main jet
NFPQ needle
Set the needle to clip 4


Funny that.. Are you a writer for Dirt Action Jayde5411??

The settings above are Exactly as suggested by Aprils Addition(Australia) of Dirt action Mag...
Any coments on these jet specs?

Anyone seen this months issue of DIRT ACTION? Issue 143.April..

Theres a 7 page write up On the WR450F ..

It shows Their recomendations for Jetting specs for better performance and fuel econemy are;

Run 45 leak Jet
45 pilot jet,
162 Main Jet,
NFPQ needle..
Set the needle position to clip 4...(not sure thats 4th down from top)

Also even better response is to Buy an R&D carby bowl..Comes with adjustable leak jet so keep the above jetting and MINUS the Leak jet of course...(all suggested by Dirt action)


One other interesting thing i noticed the mag says is to LOOSE the overflow bottle for the coolant at the rear and re-route the overflow lines out the bottom of the bike like a motorcross bike....

Doesnt say anything else on that one but wouldnt that make the bike overheat if you ditch the overflow?Isnt one of the pipes a return?

  • The Hopper Show

Posted April 05, 2011 - 12:18 AM

#12

whats wrong with the zip tye fuel screw?

  • jayde5411

Posted April 05, 2011 - 03:23 AM

#13

Funny that.. Are you a writer for Dirt Action Jayde5411??

The settings above are Exactly as suggested by Aprils Addition(Australia) of Dirt action Mag...
Any coments on these jet specs?

Anyone seen this months issue of DIRT ACTION? Issue 143.April..

Theres a 7 page write up On the WR450F ..

It shows Their recomendations for Jetting specs for better performance and fuel econemy are;

Run 45 leak Jet
45 pilot jet,
162 Main Jet,
NFPQ needle..
Set the needle position to clip 4...(not sure thats 4th down from top)

Also even better response is to Buy an R&D carby bowl..Comes with adjustable leak jet so keep the above jetting and MINUS the Leak jet of course...(all suggested by Dirt action)


One other interesting thing i noticed the mag says is to LOOSE the overflow bottle for the coolant at the rear and re-route the overflow lines out the bottom of the bike like a motorcross bike....

Doesnt say anything else on that one but wouldnt that make the bike overheat if you ditch the overflow?Isnt one of the pipes a return?


No way I was born with that knowledge...:ride:

You can learn a lot from reading....:cheers:

  • The Hopper Show

Posted April 19, 2011 - 09:58 PM

#14

whats wrong with the zip tye fuel screw?

anyone?

  • MANIAC998

Posted April 20, 2011 - 03:03 AM

#15

Hopper, some say that the Zip ty fuel screw is poorly made. Maniac

  • wanawakeboard

Posted April 21, 2011 - 12:02 AM

#16

go with a 168 main, stock is 162 on an 08... aluminum fuel screws dont work well with brass I have one but I been told I could have bought a better one...

  • The Hopper Show

Posted April 25, 2011 - 10:14 PM

#17

what fuel screw would be better? everything i read says to go with zip tye. what brand is a better brand to purchase?

  • wanawakeboard

Posted April 26, 2011 - 04:58 PM

#18

heres an old link...
http://www.thumperta...p/t-386323.html

  • William1

Posted April 27, 2011 - 03:15 AM

#19

RE: Fuel screws

Merge racing is a great one
James Dean, Kouba nad Scotts all have a brass one
Keintech has a stainlkess steel one

Do avoid the alloy ones, often nothing but trouble.
Often, the tip is poorly made. Instead of being perfectly straight, they have a slight taper. This causes the jetting to be messed up and some have had to suddenly go from a 45 pilot all the way to a 38 (which clogs easier amoung other things). Also, being tapers, it can wedge itself in the fuel screw seat. Being it is soft aluminum, it can easily break off and become jammed, possibly ruining the carb.

ZipTy is the largest manufacturer of these alloy screws and a lot of other ones are merely re-packaged ZipTy ones, just like most jet kits are really just re-packaged DynoJet ones (except James Dean)




 
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