2009 WR450 Jetting Help for Colorado 6,500 - 9,500ft

6 replies to this topic
  • Dude

Posted August 28, 2012 - 11:50 AM


Posted this in the Intake/Jetting area too, but wanted to get some feedback from those that don't frequent that thread:

Purchased an '09 WR450 used and need help dialing in the jetting...here's the skinny of what it's got, doesn't seem right:

[color=Red]1)[/color]2009 WR450

[color=red]2)[/color]conditions (Colorado) (6,500 - 9,500', 50-75 degrees, low humidity, trail riding

[color=red]3)[/color]modifications (FMF Q4 with powerbomb header, stock air box, stock motor with AIS removed)

[color=red]4)[/color]current jetting:
- Main 168
- Pilot 50
- Starter 65
- Leak 45
- Needle GDDTR 4th clip from [color=darkgreen][size=1]top[/size][/color]

[color=red]5)[/color]running issue - hesitation at 1/4 - 3/4 throttle position, black soot on pipe and plug, burn mark on pipe (sticker burned)

[color=red]6)[/color] Running issue unchagned? affected by motor temp (NO)? better or worse when hot (NO)? better or worse when cold (NO)?

  • Mtn-Track

Posted August 28, 2012 - 12:21 PM


Your WAY to fat on the main jet. I run a 152 main for the same altitudes.... see what I have on the bottom of my post and you'll get the idea.

Year: 2008
Model (400 - 426 - 450): 450
Cam Timing (WR/YZ): WR
Main jet: 152 (yes, a 152!)
Pilot Jet: STOCK
Leak Jet: STOCK
Starter Jet: STOCK
Fuel screw (turns out): 1.5 on R&D Adjustable
Grey Wire Mod (Y/N): Y
TPS Connected (Y/N): Y
Airbox Snorkel/Lid (on or off): OFF
AIS Removed (Y/N): Y
Airfilter Brand: STOCK
Exhaust Brand: FMF[color="#282828"] POWERCORE 4
Average Altitude: 5000-14,000ft
Average Temperature: 50-80F
Average Humidity: Pretty darn DRY!
Degree of Satisfaction (0-10): 9.5[/color]

Edited by Mtn-Track, August 28, 2012 - 12:26 PM.

  • Dude

Posted August 31, 2012 - 07:22 PM


For those of you in the same area that want to know...here's what I did that worked great:

Ordered the JD jetting kit:

Year: 2009
Model (400 - 426 - 450): 450
Cam Timing (WR/YZ): WR
Main jet: 160
Pilot Jet: 48
Leak Jet: 45
Starter Jet: 65
Fuel screw (turns out): 2-1/4 Zip-Ty
Needle Model/Clip position: JD Needle Red - 3rd clip from top
Grey Wire Mod (Y/N): Y
TPS Connected (Y/N): Y
Airbox Snorkel/Lid (on or off): ON
AIS Removed (Y/N): Y
Airfilter Brand: STOCK
Exhaust Brand: FMF Q4 with Powerbomb header
Average Altitude: 7,000-11,000ft
Average Temperature: 50-80F
Average Humidity: low
Degree of Satisfaction (0-10): 9

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  • MANIAC998

Posted September 01, 2012 - 02:45 AM


Glad to hear you got it working well! The "JD" jet kit helps considerably! I'm sure that other methods work equally well, but having the JD jetting chart takes a lot of guess-work out of the equation!!!

  • Leardriver

Posted September 01, 2012 - 08:56 AM


You need a 155 main, but you are close otherwise. All you needed was a $6 pilot and $6 main jet.

  • Dude

Posted September 03, 2012 - 06:13 PM


Spoke too soon...rode 50 miles of trails yesterday at 9-10,000ft and has a pretty significant off idle bog and after washing the bike today it's back firing pretty significantly on decel.

  • Leardriver

Posted September 04, 2012 - 08:09 AM


Try a 45 pilot at 1.75 turns out on the fuel screw, or with the 48 you have in it now, turn it down to 1.5 turns. A leaner main, like a 155, will help, but that wasn't responsible for your off-idle bog. You were drowning it in fuel.

Decel popping isn't always bad jetting.

Edited by Leardriver, September 04, 2012 - 08:10 AM.


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