Stock CV jetting questions...

Need some input here... 2012 XR650L, bone stock engine, exhaust, intake (EMGO 12-90450 air filter). Current jetting is stock, 50 pilot, 152 main. Location is at 5,000 feet altitude, temps vary from cool (mid 60's in the morning) to 80 mid-day for the summer, 30's in the morning to 60's mid-day for the winter, on average... Very low humidity (15% typical)...

With the Clymer manual, I get a correction factor of around .95 shooting down the middle for temps. I BELIEVE I am running somewhat on the rich side, plug looks fine. I'd like to drop a 150 main in there during my next valve adjustment but the factory manual states that "operation with a high altitude jet at less than 5,000 feet may result in engine damage".

Anyone here running a 150 main in conditions similar to mine? Any thoughts on attempting this before I leap?

Snorkel in or out?


How much ethanol in the gas there?

Snorkel is installed, ethanol is 10%...

If you suspect you are rich, try snorkel out.


Stock jetting at that altitude with 10% (10% max or an actual 10%? they like to keep us guessing here in NY) ethanol, hard to say.

Thanks Dave, I am likely attempting to solve a problem that does not exist but I wanted to get my jetting "spot on" for my locality.  I just switched back over to the paper element, which is likely why I saw my top speed drop (I drive 40 miles round trip each day, 12 of which are on the freeway) at least 5 mph...  Given that I primarily drive street, the paper element type seemed the easiest to use on a regular basis...

i would remove snorkel also, no real reason to not let it breath as easily as possible.... may make it run like a champ too....

I run in the desert...4-6 k feet daily..why do you want it so lean? I would recommend doing the airbox work, unifilter, Daves mods, and a 160/55 or 160/58 jet setup. Buy an adjustable needle jet. The improvement in performance will astound mileage drop was minimal..and the bike runs much cooler..

Many of these bikes do well with the leaner jetting, it's an odd thing, but jetting that would kill some XRLs is just right for others.

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