Winter Jetting?

6 replies to this topic

Posted December 05, 2009 - 09:32 AM


I want to get my 450 ready for winter and I have been running the JD kit all summer with great results. Its now cold out and the bike popps and stutters really bad. So do I just swap out the red needle for the blue needle and keep the same clip settings and jets in? Or DO I change those too? Thanks.

  • mxrayser

Posted December 05, 2009 - 11:22 AM


Try it and see if its better, but you will most likely have to change at least the main

  • mxrayser

Posted December 05, 2009 - 11:24 AM


Usually a couple sizes up or down on the main works for seasonal jetting for me, but I;m in California, so no great temp changes

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

Posted December 06, 2009 - 01:17 PM


Thanks man, Too cold to really get out and try any of the changes, but so far just swapped out the needle and it started more gracefully *less popping*.

  • tmoney302

Posted December 07, 2009 - 09:05 PM


The popping your experiencing is probably when coming off the throttle which in that case you can richen up your idle/mixture screw by turning it out till the jake brake noise quits. This will also help it when starting. For the main jet, you don't need much. Maybe up it 5 or 10. When ice racing, I run a 180 from a 165 on my bike and thats plenty rich enough for me down to -10f at sea level. You'll notice the biggest improvement from cleaning up the idle mixture though.

  • CaptainKnobby

Posted December 07, 2009 - 09:10 PM


during the early part of racing season here in VA. like 1st week in march it is really cold on that sunday. My 06 would do like yours in the cold but I would just turn the fuel/air screw out about a couple of turns and it would clear my 06 up.


Posted December 07, 2009 - 09:14 PM


cool thanks, Ill give it a shot:thumbsup:

Related Content


100 hrs on 2014 yz450f, shim valves or replace them? by ttr230rider6

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • Hot  79 replies

Thinking about Yamaha 250... by Arctic Pride

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  491 replies

yz250x vs 450 4t comparisons (preferably desert riding) needed by JakeNorthrupYZ450F

Dirt Bike   Make / Model Specific   Yamaha   Yamaha 2-Stroke
  • 9 replies

YZ450F 03 Sparks driving me crazy by SirAttard

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 5 replies

2016 YZ450 by CaptainKnobby

Dirt Bike   Dirt Bike Technical Forums   Suspension
  • Hot  59 replies

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.