Picked up the DJ 2152 kit.......the Kit is fine, but seems odd they don't reccomend a pilot jet upgrade too. The kit comes with several mains, new spring, needle, etc. ........no pilots. While I haven't taken it apart yet to actually look, again...... Just seems odd. On the 2009, the pilot jet isn't pressed in or something is it?
While I have the carb off the bike, I'll probably go ahead and bore out the starter jet too..........why not?
The way it was explained to me, back in the day, the pilot jet is an idle/slow running jet. Why wouldnt you want to enlarge this too? Especially if you are woods riding and doing things like fiddling with your sprockets to aid in this type of riding? Stock is supposedly a #35......I've read on here that a lot of you guys run a #40. I may consider this too depending on the input.
Thank you in advance for your input, and as always........The dude abides.
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I put in a #38 pilot and found it to be too big with my 250, no airbox lid, hmf slip on. Went back to a #35.
Now I have a 351 with a #38, but haven't yet tuned in the pilot jet setting to see if it's correct.
I just read yesterday a good set of instructions for setting the mixture screw (pilot jet circuit) correctly. Now I can't find or would paste it here. From what I remember:
1. Adjust your idle so that you can turn in the mix screw all the way in (gently seated) and the bike continues to barely run. If it dies, turn the mix screw back out a turn, up the idle speed a little and try again. Once there, your idle speed is set where you want it (I hadn't heard this step before myself so this one is new to me and I don't know how it will work for me).
2. While the bike is idling, slowly turn the mix screw out from it's seated position. Idle speed should increase. Keep turning far enough and idle speed should decrease again. There should be a sweet spot with fastest idle. Use a good ear or tachometer and find the place where idle speed is highest. Set it in the middle of this range (if there is a range). Some guys recommend going 1/4 turn or so cw or ccw of this position, but I'm not sure why. This setting should be between 1 and 3 turns out on the mix screw. If its less than 1 turn, pilot jet is too large and you want a smaller one. If more than 3 to 3.5 turns, the pilot jet is too small and you need a larger one.
3. Turn the idle speed back down if it is too fast.
I got the #38 pilot, and nearly the #40 because everyone said it was better (NOTE - everything you read on the internet must be correct, so do it, even this!! <sarcasm>). It was better and seemed to run well. Easier starting usually without the choke even when cold, lots of black soot on the tail pipe, and sucked more fuel. I could turn the mixure screw from 3 turns out all the way to seated with very little difference in idle, with only slight increasing idle between 0 and 1 turn out. Put the #35 back in and found he happy spot at less than 2 turns out. Once I went back to #35 and set it correctly, there was noticeable off-idle throttle response & power improvement.
The "power up" kit for my buddy's KLX300 replaced the #35 pilot with the next smaller size (#32 or #33). Nice off the start snap!
I concur with Scott. Remember that although the pilot effects the first quarter throttle, it is also in play all the way through the throttle range. ie less miles per gallon.
Interesting about going a bit smaller...
I have a 40 Pilot on my 331 with the airbox lid off. It's overkill.
38 would be better...for all I know, the 35 might be best.
I went up because I was having what I thought was a lean pop, but, it was more probably a slight exhaust leak. It runs OK with a 40, though...I planned on going to a smaller one next time I took off the carb, but, I haven't had to take it off, yet.
[QUOTE=durielk;471041] 1) You have it backwards....there is less air pressure driving across the throat at higher altitudes... you need to lean it out when you go higher.
2) Probably...but, that still depends somewhat on your right wrist.
Sorry, I don't know how the Mikuni pumper carb is set up.