Jetting for temperatures below freezing.

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.

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.

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!!

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.

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

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.

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:

Some people ride on ice. Its great time.

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.

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:

speedway-johann-pongau_sm.jpg?t=1261640294

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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