2007 YZ450f Jetting

Hey guys, I have a Timbersled Mountain Horse kit on my bike (for those of you who have not heard of these you should check it out, pretty awesome and fun) and I am planning a trip to Cooke City, Montana. The elevation there is about 7600' and the temp is about 14F.

 

Right now my bike is completely stock along with stock jetting. I am hoping someone can help me out with any info on what I should be using for the jetting at that elevation and temperature.

 

Where all of my normal riding is the stock jetting seems to be fine but the elevation is only about 1900'. Any help would be great!

 

Thanks guys

Hey guys, I have a Timbersled Mountain Horse kit on my bike (for those of you who have not heard of these you should check it out, pretty awesome and fun) and I am planning a trip to Cooke City, Montana. The elevation there is about 7600' and the temp is about 14F.

 

Right now my bike is completely stock along with stock jetting. I am hoping someone can help me out with any info on what I should be using for the jetting at that elevation and temperature.

 

Where all of my normal riding is the stock jetting seems to be fine but the elevation is only about 1900'. Any help would be great!

 

Thanks guys

Your motor will require a lot of fuel with that extra load, at that elevation, and at that temperature.

you better put at least a couple sizes larger main jet in it, and raise the needle up at least one clip position from stock. A larger than stock pilot jet should help also.

Definitely don't want to run it too lean, better to be slightly rich than too lean!

Thanks for the guidance! I've been searching for a couple days now on the internet and calling/emailing shops and dealers, none of which have been able to help me. Any more feedback would be great!

Thanks again!

I have also found correction factor tables on the net, telling me to multiply (mostly 0.98) by the jet size in the carb already and this should give me the size I need for both main and pilot. Should I just be using this as a guideline or is it pretty accurate?

Roughly, go 1% leaner for each 1000' increase in altitude, and 1% richer for each 12 degrees lower than your normal riding temperatures.

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