snipe, if you have the cams in the right position for checking clearance, the ACR should not have any influence on the clearance.

 

Update...
Problem still persists. I've re-jetted the pilot to 38. This in combination with drilling out the choke jet has made the KLX nice to start cold and drive away without much warmup effort. But the hot start problem is still there. As I mentioned earlier, the bike will sometime E-start if I jab at the button and catch the engine in the right point in the 4-stroke cycle. But continued holding down on the button seem to make the bike miss its opportunity to start or something. I've checked the interlock diode unit to see if maybe it is messing with the spark. It seems to be ok. I even swapped coils with my buddy's 2009 KLX250S. The problem still persists. Very frustrating.

 

When my bike is hot I need to give about a quarter of a turn on the throttle when I hit the starter button. If I don't give any throttle she just doesn't fire. It's weird coz when she's cold it's the exact opposite - if I give any throttle she just won't start (though admittedly I use the choke when she's cold).

 

Can someone explain why this bike can ALWAYS be bump started hot but RARELY with the e-start? I just don't get it - don't both methods put the engine through complete combustion cycles?

 

When you're using the e-start, the voltage may be dropping enough to get a bit weaker spark. The bump may also result in a faster spin of the motor along with all the voltage being there for a nice spark.

 

Is it not somewhat normal for 4-strokes to have problems starting up when hot? IE: you see the guys racing the bikes take a bail/stall whatever, then are in the middle of the track kicking away?

There is a really good writeup on this in ktmtalk.com, I'm trying to find it and will share when I do.

 

I've only had my KLX for about 3 months. I noticed right away that it was hard to start, especially when hot and at higher elevations. I recently added a FMF Q4. I went with a 38 pilot jet (also increased main jet), and I happened to change the spark plug to an iridium plug at the same time. Since the re-jet and plug change, the bike starts easily whether it's cold, hot, or at high elevation. I had read on the Husky forum (I have a Husky too) that the iridium plug helps with easier starting. I'm not sure if that's the main thing that improved the starting, or if the 38 pilot (slow jet) helped more, or if it's the combination of the two.

 

Thank you. That makes sense.

But...... if the voltage was dropping on the e-start wouldn't it be even harder to start cold? Don't mean to be a PITA but would like a better understanding of what is causing this problem.

 

These things run lean, somehow when hot they seem to go even leaner so there isn't enough fuel to ignite easily. If mine dosesn't want to fire with a couple or three seconds of button, I twist the throttle just a bit and it catches.

 

I Found the problem! YeeHa. I pulled the carb, and drilled the plug that covers the idle mixture screw (intake valve side of carb). Pulled out the plug with a wood screw. I then used a knife file and marked the position of the slot in the needle screw so I could always return to the stock setting. I then carefully screwed the needle screw into the seat. Stock position was about 1 5/8+ turns. I then pulled the screw completely out, and cleaned it up and blue air into the hole to clean the seat. I reinstalled it but this time increased the turns out to about 1 7/8. ChaChing! The bike starts perfect. So either the thing was set to lean from factory, or there was some restriction that I removed during the cleaning/seating process. I still run stock pilot and main jets. The needle in the slide is also stock. The only other mod was the slight enlarging of the choke jet. The bike runs super. Hope this helps others.