Hi all, I am still learning the ropes on these bikes and need help.
I have a 2009 klx250sf that is stock except for a loud muffler as far as I can tell. I yanked the carb off, will twist after cables disconnected in the future. I wanted to pull the jets to see what size they are and order larger to get rid of what I perceive as lean surge between 50 and 70 mph. 35 pilot and 128 main. Stock? Also, I pulled the needle and it has 5 grooves with an e clip in the middle one. Is that an oem needle? There were 2 washers on top of the e clip, why on top? Should they stay on top or be used to raise the needle? The needle in the manual shows no grooves in the picture I was looking at. I damaged the e clip so got one at the hardware store and put it one groove lower than middle(2nd up from bottom, should I leave it in the middle?). I ordered a 38 pilot and 130 main jet which were the next sizes up on the list of keihin jets at the LBS. I still have a stock air box and snorkel and am not planning to mod the bike further than sorting the carb out. I like my fuel economy(68-74mpg) but am annoyed at the lean surge and concerned an excessively lean F/A mix will kill my engine. Of course when it does die I want to go 351. And lastly, I live and ride at sea level, my idle mix screw was/is 2.5 turns open.


Thanks in advance, there is too much info when I tried the search function.

 

That needle looks like the 0228 that comes in the DynoJet 2152 kit - So I would assume you have the 2152 kit installed. If so, it has been installed incorrectly using stage 2 parameters (128/3N w 3 turns out on fuel screw, removal of the snorkel.)

So, 3 turns out, pull the snorkel, and ride it a while. I would not order and mix Keihin jets on the DynoJet setup. Going to 4N will richen the midrange RPM but above (about) 7k @ WOT will be unaffected.


If you are going to keep the lid and snorkel, you'll have to reset the carb using standard stage 1 parameters - Here is the instruction sheet for DJ 2152 - http://www.dynojet.com/pdf/2152.pdf

 

The washers go on top of the clip and are imperative for proper needle functioning. They stabilize the needle in the nylon "hat" ...

 

The #38 pilot is only going to help in the event that you want to pull the lid, put in a DJ136-DJ140 main, and enjoy more top end power..

 

k-ster,
If a DJ kit was used I take it that the 35 pilot is oem and the 128 is a DJ main jet? What about the clip position on the needle? On further thought, if I am lean between 5K and 7+K I would think that raising the needle one groove might do the trick and the jets I ordered may collect dust.


Thx, Dave

 

OK, I'm done editing my posts on your thread.. So re-read them please.. Yes, the #35 is OEM. Yes, the 128 is likely a DJ jet. The lower down on the needle notches, the richer the needle operations..The bottom notch is 5N. The standard Stage 2 is 3 down from the top,3N.. Phrases like "raising the needle one groove" can be misunderstood..

 

You are a scholar and a gentleman. Thanks for patiently repeating for me what you have probably said many times before.

 

Your quite welcome. Go ahead and install the #38 pilot since it's already coming. Set the fuel screw about 1 turn out, warm up the engine to operating temp, turn FS out until idle drops, then in until idle drops again, then out to the midway point between drops.
I assume your loud muffler is an aftermarket item. You really should think about getting a DynoJet #140 main jet ($2.00 from DJ or perhaps free from your local motorcycle dyno shop).. Then, at some point, you can feel the power of my dyno tested setup - 140/2N, Airbox lid off ...

 

Based on my analysis and advice I put the clip at 4N position, opened idle mix from 2.5 to 3 turns, and for the hell of it removed the airbox lid. 9 miles with 4 interstate miles later I found the midrange lean surge gone with a slight increase in power. As predicted, By k-ster, my top end is lean, made worse by removing the lid I believe. One shot in 5th gear full throttle gave big stumbles at 8krpm so I intend to use the 38 keihin pilot jet I ordered and get a larger DJ main and probably take the needle back to 3N. And can anyone identify my exhaust in the pic attached? I also discovered I have a k&n filter in the box. Except for the top end stumbles this bike is much more enjoyable to ride. I may never need the 351 bump and since I commute daily with 20 miles of interstate a 15t sprocket my be perfect.

 

Snappster, you have a LeoVince X3 . Standby, more to come.. Ok, I didn't find enough detailed pictures of it online to make a definitive determination of its' powerband emphasis. I assume you have the stock header - identify it by the stock heat shield.. It also seems that the X3 starts out same diameter as header and increases in size at some point on the way to the silencer. It really doesn't matter as DJ140/2N (lidless, preferably with a #38 or #40 pilot, near sea level) will cover a megaphone design as well as a single sized midpipe..

Your on your way toward 22hp and 15.5 lb ft torque - maybe a tad more, maybe a tad less .. As your finding out, that power increase changes everything..