The 22c mod is pretty-much a re-jet mod, it raises the needle, so it makes a smaller needle/kinda like a bigger jet. Choose which one you want, I recommend the 22c.
It gave me a little more power and better mpg. My carb does fine at 4-5k'.

 

New to the forum & I have a carb. question for my 2013 KLR. After I do the .22 cent mod, what size of jet would you recommend for my bike? Everything is stock and it seems to pop quite a bit when decelerating. I am @ 5200 feet elevation wise. I appreciate any help!

First, welcome to the forum!

Slight backfiring during deceleration ain't no thang, IMHO; may be reduced by adjusting the FUEL SCREW. Google, "Care and feeding of the CVK40" for a good primer on the carb operation, and location and access to the fuel screw. About 1.75 turns out from a SOFT bottoming is a good starting point for a stock engine, IMHO, in contrast to what a service manual might say.

The 22-cent mod doesn't affect jetting, IMHO. Rather, raising (shimming) the needle fuel-enriches mid-range operation (might not be particularly effective or necessary at 5200 feet elevation); drilling the slide vacuum port may enhance throttle response.

Otherwise, with a stock engine, and essentially stock carburetor (stock needle, but shimmed one # 4 washer), I think your stock jetting's pretty close to optimum for typical KLR650 service life, although at your elevation, a smaller main jet may fuel-lean your mixture more optimally. Your bike, and YMMV ('Your Mileage May Vary').

No harm in experimenting with jetting; everything can be restored to stock operational condition if you don't like the results. My riding partner has 55,000 miles on his '08; been from Canada to Mexico; restored his carb to stock condition, early on, and left it that way.

Diverse opinions abound on jetting; everyone has one; find what works for YOU.

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Full disclosure: Near sea level operation; 22-cent mod (one # 4 washer, 7/64" vacuum port), 1.75 turns out on fuel screw, on my otherwise stock '07. Mileage in the high 40s, mpg-wise; starts, runs fine. "What? ME worry?"

 

Damocles pretty much nailed it.

Here at 600 ft ASL I have the stock low jet,
idle screw out almost two turns, the .22 washer shim,
and to be safe a 150 main as the intake hole and exhaust
tip have been opened to a slightly larger diameter. I tend to ride
aggressively and let the engine spin into the 5's often. The 150
is probably overkill comparing that to my fear of a high rpm lean
condition. The main circuit actually does not see much service time
for most riders. I don't think it comes on until about 3/4 throttle.
That would only be during acceleration and maybe interstate riding.

The factory jetting being slightly lean is probably perfect for your area.

Have fun!,
Cheeeeeeeeeeeeeeeeeeap

 

Thanks for the welcome everybody & the great info.! I am going to give the .22 cent mod a try & I am installing Eagle Mike's Doohickey kit when it arrives.

Ride safe,
Pikester

 

installed a dg exhaust

hi im a first time klr 650 owner I installed an dg exhaust I was woundering if I should leave it stock or do the 22 cent mod. if I do the mod whats the fuel miture setting best at

 

I removed the #2 exhaust baffle too. It really helped the 22c mod. It was worth the time and the $30 tip.
I'm usually about 1500' here, I do day-trips and weekends to the Smokey's. My stock set-up was sick at higher altitude.