I decided to try some cheap mods on my KLX to see if I can bump up the power to something I can live with. Did a bunch of things this weekend, but waiting on valve shims right now before I can run it. Just wondering what you guys think of the changes and if you have any advice on anything else I should change or anything I shouldnt have done. Advice on a starting point for jetting would be great too. Im at sea level and ride normally between 5-25 degrees celcius. Bike is a 2006 and all stock before this weekend. So far I have removed air box lid, Installed a Hindle slip on, did Marcelino's cam mod, and some carb mods.

Carb mods including drilling main jet to keihin 140 size (DJ 128). Not sure if this is the best size. Seemed like DJ128 and DJ132 popped up a couple times in the cam mod thread so I though id start with DJ128. Am I in the ballpark?

I also shimmed the stock needle up 2mm and drilled the slide hole to 7/64. It seems alot of people change the needle to an adjustable notched one. Any suggestions on which one for my application?

Pilot is still stock 35. I did remove the plug over the mixture screw. Mine was at 3/4 of a turn out from seated. Is this low? IS THIS SCREW A FUEL SCREW OR AIR SCREW? Searching reveals people refering to it as both lol. Any suggestions for a starting point setting on this?

 

Sounds like you should be pretty close with your jetting, that is if you put the lid back on. You can pull the snorkel, but will need bigger main with the lid off. Also try the mixture at about 2-2.5 turns out.

 

The mixture screw controls fuel, in parallel with the pilot jet. Somewhere around 2 1/2 turns out should be good.
Change the needle to an adjustable one. The stock one will be lean in the mid range.

Ride on
Brewster

 

Lots of work there. I hope it comes together well. 128 may be just right. Play around now with air box setup (lid on/off, snorkel in/out) and see how things are rich/lean wise. Not very many here report much success on shimming the needle. There are at least two options: Kaw N1TC needle or a DynoJet kit (maybe #2206 since you already drilled the slide hole, although it probably matters little).


/

 

I couldnt wait any longer on shims so I ground mine down on the surface grinder at work today. Got it all back together and it still runs! Took it for a quick spin and it does seem a little more powerful. Didnt go too far because Its ridiculously loud with the Hindle exhaust and I felt bad riding around town with it.

I started to mod the stock silencer tonight. Have the old outlet removed and found a suitable piece of pipe (1" ID) for a new one. But I dont have acess to a welder right now to weld it in. Should be able to do it tomorrow maybe. I did start it up with the stinger removed and its still nice and quiet. Nothing like the hindle.

Ill post more detailed results when I get it running with the stock silencer again.

 

You might keep a close eye on the shims. They are case hardened. You may have ground most (or all?) of the "hard" part of the surface off.

Ron

 

happen to be reading the manual yesterday and it specifically states not to grind down the shims...it can crack and cause severe damage...

 

Well, I did do it on a surface grinder, that would be the same way kawasaki gets them to thickness. Im not too worried about hardness, a part that thin is probably fully hardened. Even if case hardened, I only took off like 4 thou. The finish from our machine wasnt quite as fine as stock, i guess fatige cracks could start like you say. Would hate to see it crack.

Im thinking they probably say not to grind them for obvious reasons otherwise you would have people sanding/filing/angle grinding these things and causing all sort of problems because they are not flat anymore.

I think ill be fine, but i do have a shim kit on order so ill keep it in mind and if i ever have the cover off the head again ill swap them out just to be sure. Thanks for pointing it out.

 

Got a chance to go for a nice ride tonight. Running the stock exhaust again now with bigger outlet. Im fairly impressed, it has noticably more power. But I have a bad bog. Mainly noticeable around 4000rpms and 1/4 throttle or less cruising around. Its also noticable as a hesitation when going through that rpm range with more throttle. Slight hesitation noticeable when blipping the throttle the match rpms when downshifting too.

Any suggestions? I think I might be too rich actually. Tried re-creating the problem (4000 rpm cruise at mid speed around 1/8 throttle) and tried adding choke and it gets much worse as soon as I start to move the choke lever out at all. Also, Im getting no popping on decelleration at all, could this also be a sign that im too rich? I have read some popping is expected with proper jetting. Setup is listed above, but I have stock exhaust with bigger outlet back on now. I did try turning the fuel screw all the way in to 1 turn, may have been a very slight improvement, but the bog is still very noticable. Probably the needle. Should I drop it down a little more or go all the way back to stock or switch it out?

Also, why am I noticing this at a specific rpm range? Same throttle range is fine over 5000rpm. Usually jetting depends on throttle range, but im new to diaphram carbs (and 4 strokes for that matter). Could it be that the engine sucks the slide up to the rich position at 4000 rpm? and its past it at 5000k? Even though the throttle position is the same in both cases?

 

Try putting the airbox lid back on minus the snorkel. You do not have a big enough main jet for no lid. Just spend the $50 on a dynojet kit, you will get the right jets and a good needle.