Do the KLX300 adjustable needle per the Cheap Mods link in my signature. It has the Kawasaki part numbers and all. I got stumbling when I tried shimming the needle, it went away when I pulled the choke on (the Kaw choke is actually an enrichener) the little bit of extra fuel mix told me it was lean. The needle fixed it fine, set up just like the Cheap Mods described. Look at the document. It worked on my 09 and my brother's 07.

 

I was actually thinking about this as I've read lots of praise for that needle. I wanna give this setup my best shot and get the best out of it. Then maybe in a couple of months try the N1TC needle, maybe even the kawasaki main.

 

Hey KLX678, I have a 2007 and thought I read somewhere that the MCM mod was not a big improvement like it is on the later models. Is that true?

 

I do not know. I'd think if the cam timing and ignitions are the same, we already know the carb is, so it would have the same effect. But I do not know if the cam timing and ignition are the same, never checked. But again, if they are, if the engines are essentially the same, it should have the same effect.

 

Miniman, what you thought you read was actually the result of old posts in the MCM thread by Jeffward .. He offered no supporting data, that I could understand, on his statement that older KLX's do not benefit as much ... You can research his postings in here and make a determination for your self.. I found no other mentions of pre-09's not benefiting in my research..

 

I would not put much credence to single case. I would look to either the real numbers as I mentioned - if the engine and ignition specs match the effects should be the same - or do the other logical thing...

Start a thread asking if any pre-2008 KLX250 riders have done the mod and how it worked. I'm not going to because I have an 09 and it works. I'll leave it up to miniman to start the thread, because he wants to know.

 

ok, continue:

4th: Went back to 126 main, kept screw at 2.5 and needle at 5N. Feels very good, still a tad rich even in 45F morning weather. Only needed choke for a couple of blocks when before it needed it for a half mile at least. Low and mid response is improved, slight hesitation due to the richness, but not bad.

5th: Kept 126 main, screw back to 2.25 turns that it had before the mcm, needle at 4N with shim. Note: for the shim I used one of the washers for the dynojet needle as I had a few extra. I measured the gap from 4N to 5N clip position and its about 32 to 34 thousands of an inch. The gap with the washer is only 17 thousands, pretty close to half. Thoughts: awesome! this feels real good specially in my real riding thru traffic, I'm not waiting as long for acceleration as before waiting for the engine to rev up. It's not earth shattering, but it just feels linear now, instead of feeling like there's a hole from 3k to 6k rpm. Not so much downshifting is needed now to be in the power curve. Top end thoughts? It does feel "out of breath" about 500 rpm sooner at the top, but it does not feel weaker, I just shift 500 rpm sooner than before. Top speed is the same in the same distance or sooner, but too close to tell. Either way, top end loss for me is negligible and does not affect real world riding.

Issues: Only one, and it's very slight. When cruising at 3k or 4k rpm and snapping to wot, it feels flat. When off the throttle at the same rpms and snapping to wot, it's very responsive, even jerks the bars a bit. Pilot circuit? Float level? Screw? Normal?

Sorry for the long post, just want to share the details with others in case it helps them. cheers

 

Thanks guys.
I asked KLX678 about the mod because his bro rides one and I assumed that they had done the mod and could give an educated answer. I'd do the mod anyway, just wanted to be a little more informed.

 

Great work with the washer and clip position measurements - So using a washer will be a midrange position between two notches.. Outstanding..

You describe the performance with the MCM+PC4+stock header exactly as I experience it.


I think I understand "When off the throttle at the same rpms and snapping to wot, it's very responsive," ... So lets see here - when throttle is closed (bike decelerating), the main jet and needle system is "off", the emulsion tube(needle jet) is primed but not being used, a snap to WOT at this point with 4.5N will empty the emulsion tube almost instantaneously giving a "shot" of fuel to the engine.. This "shot" does not occur with the same volume of fuel if you snap while stead state cruising because the emulsion tube is already being utilized and can only empty whatever capacity it has in "reserve" .. Sound about right to you? Boatdriver1790 is 136/5n and reports a puff of smoke under, I think, the same conditions of decelerating then snap to WOT which I think is PERFECT!

So if the above is actually correct, the flat feeling is a lack of "fuel shot" while cruising and then a snap.. I guess I'd try a float change - perhaps raise the fuel level 1mm ??

 

Yeah, that makes sense klxster. I'll give it a try, can't hurt anything to find out. At this point I got the carb removal and install to a science. I feel like the guys in full metal jacket taking apart the rifle until they can do it blindfolded. Not quite there yet but not far off either haha.