So, i was experimenting a bit with mcm but the motorcycle had tough time to fire up without the kacr. Turned it back to stock settings and today i tried to disable the kacr but this time with stock cam settings. Same thing, without kacr it is so difficult to start, its like it has tons of compresion and doesnt have the power to move the piston. (although when it manage to turn it it fires up faster).Battery is new, starter is new(not a single issue when kacr is on).
So my question is, is this normal? What can it be? I mean it definitely sounds normal because its exactly what kacr do, (reliefs compresion) but i was wondering because many people just disabled it to make the mcm mod without any issue.

 

I didn't have problem one starting without the KACR. It was more of a headache with it and stock timing, it would crank and crank, virtually never started without turning over 10-20 seconds warm or cold.. After jetting and MCM it starts near instantly, choke off within 10-30 seconds. Starting is more about the jetting than anything. Do whatever research needed to see what your jetting is and if it is stock at least go to a bigger pilot jet. I did all the changes listed in D. Pippin's KLX page.

 

It's EFI

 

Since we know there is no problem with disabling the KACR, we therefore know there is something wrong/odd with your bike.

I'm thinking you go back to the basics - Good battery ? Good starter ? Good wires ? , Good connections of all wires ? Grounding connection issues ?

The problem is probably somewhere in the above..

 

All those checked and are good. New battery, new starter, new rectifier, wiring checked, ground checked, voltages checked.
I don't thing it makes sense anyway, it should have had a problem with kacr on if it had the above issues.
Was thinking either something wrong with my compresion or maybe its because im riding in freezing temperatures

 

I believe you hit upon the answer.
Cold temps reduces battery strength.
Try starting while jumped to a car battery as a test

 

Started my jetted KLX250 with compression release disabled at 8° F (-12°C) without a problem, Had my KLX650 with compression release have problems starting at around 15°F. One bike needs the compression release, the other doesn't. The kick start KLXs probably do need the compression release and odds are the reason it is still there is because it was there on kick start bikes.