Okay so I recently put in my 340 with two bros system and snork removed. 128 dj jet, needle 3rd clip, screw three turn out. Awesome power, 1st gear wheel lofti torque.

My quest for mpg,
Needle second clip, then tuned air screw with off idle procedure. Guessing 1.75-2 turns out.

Managed 65 mpg city. The bike lost it's *****. And it's a machine to be timid with. Plug is still border line gray.

If I want to reek into the ignition phase I'm going to have to have this even richer than before. Probably 132 main and 4th clip.

I love how my civic tuned would get 40-45 mpg and put out 30 more hp. All because of a lovely thing called fuel injection.

Grrrr.
Makes me so mad. Now if I want to go to the track, I have to change all my settings so i can stop on it safely and have power.

I'm going to have to figure out how to work a micro squirt.

 

Did you figure out what your fuel mileage was prior to leaning out your settings ?

Modern carbs really aren't that much less fuel efficient than FI. FI is "easier" to tune and can be tuned much more on the ragged edge of lean than carbs thus meeting emissions requirements. Most motorcycle FI systems are throttle bodie injection anyway which is little more than a glorfied electric carburetor.

I think your grossly overstating the "benefits" of fuel injection.

 

compairing a car to a bike is a bad idea, as they have little in common. personally, i think its the big bore that did most the damage for you. i have all but that, and still get near stock mpg. and how the f are you getting 40-45 mpg out of an si civic (or 30 hp in fact). a 89 hx crx gets figures like that, and the internet says its average is 23 city/32 highway. i know intake, headers, and exhuast actually help mpg, but even my 97 civic ex (1.6 vtec) with those got 38 mpg, but that was after 6 hours on the i-10 at 70. normally it was about 32 mpg. not trying to hate, just trying to help you realize 60 mpg aint nothing to shake a stick at.

 

Civic was a full intake header exhaust, bumped timing, I-vtec cam phasing, cruising speeds where able to be leaner from the better flow. It was Cobb tuning btw. My old 89 civic sedan got 50 mpg avg but it was as safe as a tin can could get. It was thirty hp mid range btw.

 

What I'm trying to say is I wish I could reap the benefits of the full power of my setup. Before trimming e fat I would get 50 mpg to 54 mpg.

 

And he revs that civic to 10,000 RPM, too. It must be an amazing car. FI is great, but not that much better than a modern carb on a bike, if it's properly tuned.

Stop wasting your time reading plugs on a small single. With todays fuels, and the way singles run, it can't be done, and it's a total waste of time.

 

What's my civic got to do with it. And it is an amazing car. 2.0 litters of fuel efficient fury. So If I don't read plugs then what. I think I might get an afr gauge and mount it in the end of my exhaust.

 

sw0...you're putting way too much thought and effort into this bike. It's a KLX. I love mine, but it will never be a "AA" fuel, Formula 1, Supercross, Indy 500, Daytona 500, or Dakar winning type of vehicle. It's a reliable, affordable, fun bike that spans the pavement/off road gap with a good degree of capability. Do the basic mods and perhaps even a bigger bore kit of some kind, and then ride the heck out it. The need to pursure much more than that, and perhaps you've chosen the wrong bike.

I spent more money on the suspension than any other single element of this bike, as I put a high priority on off road capability. No, I don't expect KTM type suspension performance on this little bike, but a dramatic improvement was easy to obtain on the mediocre suspenders on this bike. Your priorities may be different. But if they revolve around making the engine in this bike some kind of fire-breathing monster, I don't think that will happen without a noticeable cost in money and lost reliability. I looked at the suspension mods as doing no harm whatsoever to the reliability of this bike, especially for the return it yielded. Pushing the envelope on the engine seems a little counterproductive to me...and I'm not talking about a bigger bore, as that doesn't really reduce reliability if you don't go crazy on the compression.

And sw0, maybe it doesn't have as much to do with what you might ultimately do to your KLX, as it does with your apparent hand-wringing over all the possibilities. What's that Nike commercial say?..."Just do it!"

 

Who the hell cars about MPG... thats why i have the KLR650, it gets 58mpg, and its my commuter. The KLX is the FUN bike. could care less about MPG.

 

And on that note, EMS, I was wondering why his MPG was allegedly so low...actually I don't think I saw a true before-and-after number comparison. On MPG in general, I think I've read in some cases where some folks on their bone stock KLX's are getting in the 60's and even 70's on straight pavement/highway cruising. But...do any of us who've ridden a bone stock KLX really want that level of mileage at the expense of dealing with a totally anemic bike?

And on the issue of mileage and a modded KLX, I don't cruise long stretches of pavement or even do commuting on my modded KLX, so I can't quality my highway mileage. But even with a 300 cylinder, full Muzzy, full airbox mods, and jetting mods, I'm fairly impressed with the high 40's and high 50's MPG I get with regularity doing some real off road stuff. I can't imagine my bike getting less than 60 MPG if I were to just cruise on the pavement. I think this bike gets awesome mileage. I had 4 different XR250's in the 80's...all with aftermarket pipes and jetting mods. Off road mileage was always in the 30's, and the power was shy of what my 300 produces. I don't know...I don't see much to cry about on the KLX's mileage unless something is screwed up.