The detailed installation of the cylinder 300cc I followed another post in this forum. The carbureted model is the same in this regard.
I do not know how they work EJK driver, hope it's not difficult to adjust. I am very happy with the Power Commander V even allows me to have two maps I can select the configuration and running. One racing and other savings.
I leave some videos of my bike.

CRF450/KLX
nuevas rutas 17/09/11 - YouTube

CRF450/KLX
http://www.youtube.com/watch?v=RaHzg...eature=related

GasGas EC250/KLX
http://www.youtube.com/watch?v=_KYS2SOyaDQ

I was lucky enough to try an original KLX300 in 2000 and I can say with knowledge.
The main difference is that the carbureted model is more instantaneous and abrupt at low rpm. My klx250/300 EFI is much smoother and enjoyable at low rpm and then in the upper rpm is stronger than the KLX300. The lion is a small KLX250/300EFI disguised cat.

Nice videos Jeff, Great riding territory. Well done. I hope to fit the 300 kit on the week end, if my EJK arrives. I assume the EFI will be too lean if I install the 300 without fuel controller fitted?

Yes, very poor. It does not work.

Hi all.
I installed the EJK controler. Very simple operation to plug into bikes injector input, connect a ground wire, remove O2 sensor and overide with a supplied plug in.
The unit mounts onto the bars where you can see to make adjustments to fuel flow.
The EJK comes from Dobek pre set for stage 1 mods. Very simple to add or subtract fuel by selecting the correct mode, then pressing plus or minus button. Their website has an interactive demo so you can learn how to tune the unit before attempting it on your bike.

How do you rate the controller?? Hows fast is your bike running?

Hi Joel, I have not done a high speed test as yet. I have to get down the mountain and on to the one piece of highway that allows WFO. Will get to that sometime. There is no major fireworks with the controller, just feels a bit smoother and cooler running now that the mixture is richer. Seems to rev harder in all gears. Coming out of slow corners in second the front wheel comes up easier. I do not have acsess to a Dyno on theb Island so no scientific results, only feel and sound. The bike is now night and day compared to when I first rode her home in stock trim. I am now at the end almost of mods to improve the stock 250. Last two things will be Marcellino mod and a MegaBomb header, to satisfy my curiosity. After that I will fit the 300 kit thats waiting on the shelf.

OK fitted the 300 kit, now the troubles begin. I have managed to tune the fuel flow so the bike pulls hard in all gears, from cruise to acceleration and up to full throttle, using the EJK.
The problem is, from idle to 1/8 to 1/4 throttle, the bike runs rough, hesitating, then surging hard onto 1/4 throttle. Will not cruise smoothly at speed using minimum throttle. Backfires and pops on deceleration. Any suggestions and advise on what causes this condition. Too lean? Too rich?

possibly too rich
look at the color of the spark plug, can serve as guidance

Jeff is your 300 running perfecttly from idle to 1/8 throttle using the Power Commander maps? How difficult was it to tune? What effect does the secondary throttle have on the EFI? Do you think removing it will help my problem?
Sorry for all the questions, but the 300 kit has really messed up the smooth low rev riding now. Feels like an MX racer...