Get the LM-2, install it, and you and I can start a beautiful friendship..
You should do the above BEFORE you start re-jiggering up the carb internals as baseline logs for "as delivered" are needed before "tampering" with the carb is done.
Doing a bunch of internal mods all at once may not be needed - and can be a nightmare to "unwind" if the logs report bad fueling after doing them..

 

its a no brainer to take a baseline log before changing stuff and making 1 change at a time, or at least i would think. i meant to take out all the jets to record the base settings but i got too excited and installed it immediately. from what i could gather from a few sources the "stock" jetting is as follows.
Main Jet- 130
Pilot Jet- 12.5
Needle- 9DZH6-50 Clip- 3rd from top (middle)
Needle Jet- P-8
Air Jet- 1.0
i ordered multiple sizes of each to be able to try a few different combos. jets and LM-2 should be here by the weekend. i just need to make an insert to stick the O2 in the end of the muffler or figure out a spot to weld in the bung on the exhaust.

 

Keep us informed as you go forward with reading air/fuel and the changes you make to address it. I'll be interested to see how your final numbers compare to some of the setups we've come up with here over time.

 

The WB O2 that comes with the LM-2 has specific mounting requirements - which must be adhered to in order to get accurate readings during varied riding sessions as well as insuring that the sensor has a long life span.

The stock location used on the newer bikes will be perfect.

 

LM-2 came in and i got the O2 sensor installed. it took a few rides/datalogs to get familiar with the LM-2 and get it set up properly to read AFR and RPM. once i got it going i got some real good data, not quite what i was expecting but thats the point of this test & tune. i checked all the base jets and settings, the above post was correct. i did some tweaking and made improvements to where i need to buy additional jet sizes to get to where i want to be. it feels much better than it did at the start but still needs more refinement.

base log had AFRs around 14.3:1 @ idle 7.9-8.6:1 @ light throttle cruising 14.9-16.2:1 @ WOT
very rich then leaned out, made some changes to end up with the following
13.8:1 @ idle 11.8-13.2:1 @ light throttle 10.8-12.2:1 @ WOT

i will post the full results tomorrow with what i changed and how it effected the AFR. it will likely need a smaller pilot jet and bigger main jet, plus i may get a few more air jets as well

 

You're making history - and becoming this planets' KLX+TM36 "go to" person !
You've been a long time coming.. PM sent..

"base log had AFRs around 14.3:1 @ idle, 7.9-8.6:1 @ light throttle cruising, 14.9-16.2:1 @ WOT"
Anyone running the setup that creates the above fueling should stop riding their bike until corrected.

 

Once you list an exact setup, and its' logging results, we all will need to assist you with fueling corrections.

We will need the "TM36 using members" to provide insight into which components are needing "attention" in order to fix the fueling issues.

 

Nice write up, Scubie. Thanks for providing the numbers.

May I ask where you sourced your TM36?

 

thanks Forest, ill try to provide all the info i can. I got my TM from Ebay. theres a few places i found them but ebay ended up being the cheapest. also, how do you like the 13/50 sprocket setup? i want to get 13/52 for the woods since i was never really out of 2nd gear.

now for all the information i've gathered in the last few days
BIKE SETUP: 2010 KLX250s Stock Bore, FMF PowerBomb & Q4, K&N Air Filter, Lidless Air Box, and MCM. AT SEA LEVEL
TM36-68 OEM SETUP
Main Jet- 130
Pilot Jet- 12.5
Needle- 9DZH6-50 Clip- 3rd from top (middle)
Needle Jet- P-8
Main Air Jet- Open
Pilot Air Jet- 1.0
Accl. Pump- 1/8 to 3/4 Throttle
Idle Mixture Screw- 1.75 Out
Start up and idle around 1,200 RPM with choke OFF the AFRs were between 14.2 and 14.9
Light cruising up to 1/4 throttle the AFRs were between 7.9 and 8.6. i was not expecting it to be that rich.
Light to medium cruising between 1/4 and 3/4 throttle wasn't much better being around 9
After 3/4 throttle it started to lean out and was between 14.9 and 16.6 at WOT

The first change i made was swapping the needle to 9EBY01-51 with the clip in the top groove. everything else stayed the same. went for a little ride
idle stayed the same.
light to mid cruising up to about 1/2 throttle the AFRs were between 10 and 11.6
light to mid cruising 1/2 to 3/4 throttle AFRs were around 12-13
WOT did not change

Next change i made was moving the clip down 1 notch
AFRs stayed pretty much the same same, only slightly leaner up to 1/2 throttle
light to mid cruising up to about 1/2 throttle the AFRs were between 10.6 and 12.2
light to mid cruising 1/2 to 3/4 throttle AFRs were around 12-13
WOT did not change, 14.9 to 16.2

clearly i need a bigger main jet but i only got the 2 sizes smaller not expecting to go in the other direction. i put the airbox lid back on without the snorkel only to try and get the main fueling into an acceptable range until my new batch of jets arrive. this worked and did the trick bringing the WOT AFRs between 10.8 and 12.2. everything else pretty much stayed the same.

to try and bring the light throttle AFRs up i installed a bigger Pilot Air Jet going up to a 1.1
light to mid cruising up to 3/4 throttle the AFRs were between 11.8 and 13.2
3/4 to WOT was between 10.8 and 12.2

i stopped my testing here due to the lack of jets. it feels better than when i started but i can still feel it wanting more. i believe the AFRs are now in a safe area to be riding around a bit. ill update in a few days when i get even more jets. i ordered 4 main jets bigger than 130, a #10 pilot jet (because thats the smallest), a P-4 needle jet, and 5 more Pilot Air jets.

 

Upping the main jet size - with all other components staying the same and at the same settings ( clip, etc) will make all ops richer. So adding a bigger main jet as a stand-alone mod will NOT work..
The fact that creating a restriction to the air intake ( the lid ) creates a better WOT fueling would seem to suggest that the/a main air jet is too large...

Anyway, there is no way to accomplish good fueling with a shotgun attack:
Step 1. Create proper WOT fueling - which means it stays between 12.7 and 13.0 Any engine op areas lower or higher is power lost.
Step 2. Modify ( tweak ) components in order to create proper fueling for all other ops without destroying the WOT fueling. In general terms: Low rpm steady cruise ( below 6k rpm) 13.5 - 14.5 Higher rpm steady cruising in higher gears 13.0 - 13.5


After step 1 is done, step 2 will mean a careful analysis of which needle ( and possibly other items) to use to do-up part throttle without killing WOT.