Jetting for temperatures below freezing.


10 replies to this topic
  • rmcr250r

Posted December 22, 2009 - 03:36 PM

#1

Whats a good jetting setup for a 09 yz450 in temperatures below freezing? And while im here what type of oil is best for these types of temperatures.

  • grayracer513

Posted December 22, 2009 - 04:50 PM

#2

If you have a baseline jetting for say, 70 degrees, compensate for the low temps by going 2% larger for each 15 degrees drop in temp with the main and pilot. So, if you're at 25 degrees, and your 70 degree jetting was 45/165, go to 48/175 or 48/172.

You manual tells you what to do about the oil. Any good 10w-40 is OK down to 10 degrees. A 10w-30 can be used, but I wouldn't unless you expect temps to stay below 60.

  • KX250Hef

Posted December 22, 2009 - 04:59 PM

#3

another thing you may want to chang is the plug. the manual on my 600's tells me to change the plug in cold weather riding....it makes a BIG difference!!

  • rmcr250r

Posted December 22, 2009 - 06:57 PM

#4

If you have a baseline jetting for say, 70 degrees, compensate for the low temps by going 2% larger for each 15 degrees drop in temp with the main and pilot. So, if you're at 25 degrees, and your 70 degree jetting was 45/165, go to 48/175 or 48/172.

You manual tells you what to do about the oil. Any good 10w-40 is OK down to 10 degrees. A 10w-30 can be used, but I wouldn't unless you expect temps to stay below 60.



right now its stock jetting with 160 main and 45 pilot so ill gives those two examples a try. With the stock jetting it ran pretty crappy in 50 degree weather so i guess ill have to experiment.

  • psmith85

Posted December 22, 2009 - 07:13 PM

#5

What the heck are you doing riding when it is that temperature?

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  • highmarker

Posted December 22, 2009 - 07:46 PM

#6

Use a 10w30 that doesn't have the starburst 'energy conserving' symbol on the label. Many of the "high milage" oils fit this, some don't.

  • rmcr250r

Posted December 22, 2009 - 08:19 PM

#7

What the heck are you doing riding when it is that temperature?


what else am i gonna do while waiting for the tip ups to pop up:smirk:

  • Diode663

Posted December 23, 2009 - 06:16 AM

#8

Some people ride on ice. Its great time.

  • tmoney302

Posted December 23, 2009 - 11:25 PM

#9

I ice race my 450 in the winter. It's a blast to be able to run a bike in 5th gear though corners, dragging a peg. I never thought riding in circles would be so much fun.

  • grayracer513

Posted December 23, 2009 - 11:39 PM

#10

I never thought riding in circles would be so much fun.

You should give speedway a try sometime. 170 pound bikes with 60 HP, 0-60 in 3 seconds, no brakes. :moon:

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  • tmoney302

Posted December 24, 2009 - 12:13 AM

#11

Yeah that looks like it would be a blast. Those bikes are set up nice. I wouldn't mind having one of those for the lake.
This is my ride. #59 is the guy no one can touch and he rides a 20+ year old yz250!
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