KLXSTER,
My local dyno operator/shop claims to carry no jets in stock as most bikes they service have fuel injection. And since I got my 38 pilot jet in I am about to call up DJ and order a new main jet. You preach on the 140 for your set-up. Do you think the MCM makes a difference as far as jetting needs go? I am reading on it and I am unsure only on the ACR repositioning...how can I do it in my garage for free and not break my cam. If you did it are there any pictures of the tooling you used/made? Any idea on the pressing force needed? would a gear puller/clamshell pull it? I will probably do it soon. The cam timing change looks easy enough. And since I am at sea level vs you at 500' I would think that a 140 could be slightly lean at WOT 8000 rpm. SO...as the jets are only $2 apiece and shipping may be a bit more, I might as well get several jets and experiment. Any idea on what they charge for shipping? I am thinking 138,140,142,144, & 146 sizes depending on shipping cost. Any thoughts?

 

Ok, from the top.. I believe the MCM requires slightly more fuel below 8K and slightly less fuel above 8K compared to stock timing. I believe the difference is quite small and not a jetting/setup concern. This belief comes partly from numerous members using my setups on non-MCM bikes with great success.

No pictures of my ACR removal. All you need is a large punch (drift), a small sledge, and the ability to create a support for the cam. I mounted up my support and cam on a large vise on my work table, and drifted the ACR out. I re-positioned it and drove it back in. It's a shame for anyone to go to the trouble to reinstall the ACR - it's useless on the KLX.. There are photos in here of cam supports others have made - I simply made a 2 piece collar (clamshell) that clamped (in the vise) on the shaft portion of the cam.. The large drift and small sledge hammer make the rest easy.. BUT you don't have to do any of this - all you need to do is pull off the spring on the ACR and it is deactivated. Takes 5 seconds, and your done with ACR issues.

The altitude differences are too small to affect jetting choices and setup.

Shipping costs from DJ runs me about $11.00 (Texas) so getting a bunch all at once is the best idea..

The DJ140/2N is, so far, the best setup I have found. It does a pretty good job of keeping WOT AFR between 12 and 13 to 1.. Your stock header and slip-on should be a better match for 140/2N than my full FMF system. You should need more fuel down low and less up high than my bike - so, from the charts, you're likely a perfect fit! ..... Here is the problem, the bike runs great even when grossly overfueled. I am still running 150/3N and I love it despite the Dyno results.. 140/2N produces better curves.. If you are going to experiment with jets larger than DJ140, your going to have to also experiment with 1N on the needle in order to not over-fuel the midrange.. I intend to try 144/1N in the near future.. Neonarc discovered that the DJ washers equate to a 1/2N when one is put below the clip and one above..

If I were ordering jets to play with, I'd get 136, 140, 144. Those will alter AFR 0.4:1 from another - about half a point. I'm not sure 138, 142, 146 would produce a noticeable difference except on a dyno..

 

It's a shame for anyone to go to the trouble to reinstall the ACR - it's useless on the KLX..


Have other people simply removed the spring with no ill result?
Why did you reinstall it, you could have just left it off? Does leaving it off cause a problem? Why did Kawasaki engineers add the cost and complexity to the design if it is useless?
I guess I am asking because I have yet to open the top end of the engine to see how it operates. I guess that will be coming soon as I am past 7500 miles and need to check my valve clearance and plan to do the MCM mod while I am in there. SO much for not modding my engine. And I still would rather learn from others' experience than guess my theories correct.

 

At the time I did my MCM, the uselessness of the ACR was not known. Now it is. Members have pulled the spring, removed it, and fashioned a wire to hold it open (deactivated), with no reports of ill effects. All it does is to lessen compression during the first few RPMs at the moment of startup. Made even more useless by the fact that a properly done MCM (+properly setup up carb) starts instantly - before you can even get your finger off the button!

Do the MCM, 140/2N, pull the lid - do 'em carefully and correctly all at once and your DONE ! While I may find a slightly better setup for near sea level in the future, it will surely not be a large increase in power levels over 140/2N..

BTW- It would sure be nice if your dyno shop would cut you a deal on a 2 run (or more) "package". Mine charges me $30, at this point, for Engine speed + AFR runs (each run is 3 pulls).. Getting the AFR chart is what your really after.. Sure, if your running the stock rear tire at 30psi, and SAE correction factor on a DynoJet dyno, etc etc, your numbers can be compared to mine..

 

I intended to install the 38 keihin pilot my LBS sold me. When I pulled the one out of my carb it is way different looking. I doubt the larger new one is correct or will work. Am I mistaken? WTH did they sell me? Did I pull the wrong doohicky out thinking it my pilot jet. It's the smaller one.

 

Yep, that ain't right.. It'll be ok to go ahead with the stock pilot jet for now - just back out the fuel screw 3 to 3.5 turns..

 

Snappster.. In case you a little new to the CVK - the pilot "does" startup, idle, and transition to needle.. That is the AFR's the Pilot jet and its' fuel screw controls in the RPM band. It's not a critical component in the seeking of HP/TRQ increases as the stock #35 will work ok even at sea level - it'll just be lean and can cause "pops" on decel.. If it weren't for the decel issues, I wouldn't have replaced mine..

 

This is a jetting sideline, a slight divergence from the main topic.

I still get so curious about those 12:1 and 13:1 figures since again I have just read in print in the Service section of Cycle World june 2015 pg 84 to quote:

"Emissions is the primary reason a factory has to deviate from teh theoretically ideal air-fuel mixture of 14.73:1...
Maximum power, for example, is typically achieved the 13.51:1 range, (as in context)"

The 12 and 13 figure that has been used here has always registered as too high based both on the original 14.73 theoretical and what apparently has been used by a lot of tuners over the years of 13-14:1. Sounds like 12 would be a bit rich. That was what I've heard for decades until this forum, then 12 was the goal, but why? Especially when it seems the people with access to the greatest of tuners still holds at that 13.51:1 figure.



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Check your parts against this list:

16009-1912 Kawi Needle-Jet, N1TC
92037-1401 Kawi Clamp, Jet Needle
92143-1667 Kawi Collar
Needle clip slot 2 down from the top
92063-1069 Kawi Main Jet #125 or 92063-1074 Kawi Main Jet #128
92064-1108 pilot jet #40 Air screw at 2 turns out to start
drill the slide vent to 7/64ths


There is a trick to determine if you are lean or rich at your rough spot. Reach down and pull the choke on. It isn't a true choke, it is an extra enrichener circuit and will add some fuel mix. Bog lessons or goes away you're lean in the middle.

I have used a fuel adder system to take care of lean spots on both my KLX650 and 250 along with another bike, about 25 yr experience using them. I use a Dial-A-Jet which allows additional fuel draw when lean. Does nothing when over rich.

Carb off once for the brass and DAJ, not since. May not have that nth horsepower, but it runs better than stock. Oh, I do have the Marcelino mod on mine and locked the compression release disengaged.

 

Just went to the garage and it is indeed a Keihin carb on my bike. The pic attached is of the two jets I ordered before learning there was a DJ needle in it. Anyways, I placed an order with DJ yesterday for several main jets so I can clean up the stubling at 8krpm that did not exist before I removed the airbox lid. And I really appreciate all the knowledge cast my way.