Jetting For Cold Desert Riding

[duke]

Current specs are 155/45, resulting in good performance, nice brown colored plug and acceptable spooge emission. However, these symptoms were found in 68 degree plus weather. Now I plan on a venture to the desert this weekend and the temps are expected to be around 38-45 degrees. Since a large portion of the time will be spent traversing steep hills and sand washes, read wide open much of the time, I am considering the use of stock OEM jetting specs. Any comments?

 

[MaicoCPA]

On my KDX I only ride So. Cal desert and it seems like the temperature in the afternoon can be up to 30 degrees warmer than when I first start riding in the AM. On my stock 200 I think a 158 main is still a little rich for 60F degree dry desert riding. Might be just right for lower temps, though. I personally wouldn't go back up to 160 from 155 without trying 158 first.

 

[duke]

Morning highs should hover around low 40's with the afternoon being around low 50's as the highest temp. This was according to Weather.com, so perhaps the 158 will suffice. What pilot size are you running in the desert? BTW, I havent been to Red Mountain. What can I expect? Some of the area we will riding is to be composed of those areas most often used for hare scrambles and hare and hounds

 

[MaicoCPA]

I'm using a 45 pilot. I'm not sure where Red Mountain is. Is it north of Lancaster? Maybe that's Red Rock Canyon I'm thinking if. Have only been there once, in '97. It was plenty cold in November of that year. Lot's of rocks, of course.

9 out of 10 times when we go to the desert it's Wild Wash off I-15 north of Victorville. All kinds of terrain: sandy washes, rocky hillclimbs, single track, long and fast telephone roads. Oh, and whoops, lots of whoops. Being near the interstate it has excellent cell phone coverage. Funny how that wasn't a factor where we went riding ten years ago before we got those stupid phones attached at the hip.

 

[m0rie]

If your talking about Randsburg or Red Rock Canyon you'll be just fine with the OEM 160mj,48pj jetting. Your mileage will suck, 40mi tops from your tank but you'll be plenty safe for extended WOT.

 

[duke]

That is the area to be ridden. I dont mind the OEM jetting specs beginning to take its toal in performance due to the weather getting warmer as the day passes. What I dont want is to be about ten miles from the truck, tackling a hill and go pzzt as the piston freezes up in the barrell from too lean a condition. Thanks all