‘I put a 36mm Lectron metering rod carb (similar to an APT Smart carb, but more better!) on my 2013 KTM 200 XC-W. It's bordering on magic. Smoothed out the power a bit, making it a little more linear, but still good and fun when you twist the throttle. My fuel economy went from (pay attention, I'm going American on you here) 25 MPG up to 35 MPG. This mileage has been consistent for tight & technical trails as well as faster riding. That will get me something in the neighborhood of 130 to 140 km on a single tank of gas. I've ridden from sea level up to close to 8000 feet elevation with no change in power, throttle response, idle or run-out all without changing a thing - it carburates perfectly regardless of elevation or air temperature. Drool out the back of my muffler has disappeared. Other than all that, yeah, it's probably just a gimmick.
"Just one quick note on how a cut-down 38 works on my YZ250
HOLY CRAP - they're not kidding
I just bolted it on (the longer throttle cable is necessary on YZ's) - pulled the choke - kicked it twice and ......
She idles like a kitten - pulls from maybe 1000 rpm lower - is smoooooooth thru the mid (so smooth is seems a little less pipey) - and then over-revs by maybe 1000 rpm more. (I had no complaints with the carb I replaced - it just didn't seem as crisp as I wanted - and with the Lectron the bike rides - and sounds - like a factory race bike)
I haven't even touched an adjustment yet. One odd thing to note is that I swear that it doesn't ding-a-ding-a-ding as you slow for a corner."
Just thought you would like to know. 1989 KDX. Carb works great. Started with two kicks, can drive away in under a minute. It used to be extremely cold blooded and would take 5 minutes or more of warm up before you could drive away. It has a lot more low end power, very little smoke. Engine is definitely running warmer but with no overheating or leaness. I have had not had a chance to fine tune the jetting. It was surprising close right out of the box. Just for reference the carb will not fit perfectly vertical due to the frame tubes. It seems to have no effect on the running quality.
Very happy with the purchase. Great product. May put a pair on my sled someday. Have you ever had anyone put Lectron's on 2004 Skidoo 500SS? It is the 600 cc carbed version.