I just bought this bike a week ago, and I have been struggling with the carb settings.

First ride impressions were that it seemed there was very little response at the initial throttle input. For example, trying to blip the throttle over a small bump, nothing there. So, I did some research on here, and bumped up my pilot to a 38. Stock was a 35. It still does it. Since my bike didn't idle at all from the dealer, I figured I would try to turn up the idle to at least a barely idle. In the past, on my two strokes, I never really had my bikes set up to idle, but figured maybe this has something to do with it. Any ways, I tried turning the idle screw all the way in and all the way out, and got no response.

What am I doing wrong?

I also ride a CRF250.... am I just not used to the two stroke? If that's it,, I have a 2009 300XC for sale:bonk: . Hopefully there is an issue, that I can resolve, and I can get this thing dialed in cuz, it's a friggin blast on the trail!!!!

Check the back few pages of your owners manual it gives you a jetting guide. Sounds like you need to move the needle up a spot or two to lean the bike out a little bit to get some of the snap back into the throttle. I have a JD jetting kit I run the blue needle for 60degrees and below and the red for anything above 60. If I forget to change the needle I have the same problems you are having. You should have gotten a second needle in your bag bounce the part numbers and clip position off your owners manual and see what one will be best for the temperature and elevation. Page 71 in my manual might be the same in yours.

I have been saying this a hundred times on the new bikes....they have a high float level from the factory and it affects the first 1/3 of the throttle. once i lowered the float level 1-2 mm i got instant response and twice the gas mileage. if yours dribbles gas when it is leaned over only a little you will know for sure, but check the level anyway. what is nice on the 09's is all you have to do to get to float and jets is remove the seat, throttle top of carb, and tank and loosen clamps and twist it to gain access. way easier than pulling subframe and or airbox boot. do a search on here and ktmtalk for hundreds of posts on this issue.

Joe

First I have heard of it but I don't have that problem.

I am going to check the float level tomorrow. I'm also going to experiment with the needle.

Any idea why I can't get it to idle?

Does any one elses idle?

My float level was set really high. I lowered it, and changed the jetting, and it's much better now. I still have to test it off road, but simply rippin it down a dirt road, it feels much better.

Extreme said:

What altitude are you riding at? And, tell us what you finally settled on. Thanks.

JPDad said:

I ride either at sea level, and at about 5000 feet in 80 degree weather. I will have some results later this week.

Extreme said:

two strokes dont really "idle". in fact, you dont want to just let them sit around idling to warm up because you will foul the plug at some point. you just gently blip the throttle every few seconds while warming it up, then when you can feel heat at the top of the radiator, let 'er rip!

JOE

trailmeisterjoe said:

+1
I always check the float level on new bikes &
they are almost always set too high

I set them a little lower than the correct spec so you have to lean the bike
way over before the fuel spills out

My friends '09 300EXC "idles" nicely. But trailmeister is right, don't let it idle too long or you'll foul the plug.

Extreme i just got my 09 300xc about 6 wks. ago. My jetting was very rich on the bottom and middle. I also ride from 700' to 5000' , this is my set up. Main 165 , JD needle red #3 to #4 slot, #8 slide, #35 pilot, air screw 1-1/4 out. This gives good plug color after a full on plug run , and it pulls very strong and smooth from bottom to top.

Also my mix ratio is 50/1

trailmeisterjoe said:

Mine does this at minimal lean angle. New to this bike, so thanks for the advice.

OK, so... I went leaner on mid and top.

I have:

38 pj
2nd clip stock needle, was at 4th position from factory
162 main

lowered my float level
adjusted my AS until crisp

I also installed the red PV spring.

Just got back from a ride, and it's 100% in the opposite direction. Before these mods, it had no throttle response and huge lack in power, plus the feeling like it need to be revved out, to clean it out(rich feeling).

Now, it leaps out from under me, is rediculously sensitive to throttle input, and halls butt!!! It's actually hard to ride now.

I've been riding/racing for 30 years now, and this is the first time i've had to tinker this much, maybe I've been lucky. Don't get me wrong, I love the bike, I think, but, it just went from too slow to too fast. I just read a 3 page thread on KTMTALK, on how to tame the 300..... Tame a bike? I don't get it. last time I checked, we all wanted our bikes faster. But the feeling I got from riding the bike today, was the same feeling I had when I tried to go back to 2 stroke several years back, hated it. I love the calm feeling of the 4 stroke, but I want the power when needed.

So, I'm starting to loose wind in my orange sail. I have such a hard time swallowing the idea of messing up the jetting so the bike doesn't run so good? :bonk: That's pretty much the advice i read on ktmtalk.

I do have the ignition curve switch, and no, I didn't try it in the out position :banghead: I keep forgetting I have that handy lil switch.

Is adjusting the PV adjustment screw noticable? or should I go back to the yellow spring? and will either help with the low end hit? or am I just going to have to get used to it?

Install the yellow spring, ride. Install the green spring, ride. Don't adjust the brass screw yet. I think PV adjustment will get you where you want.

I liked the green spring with a couple turns of preload on it, initially. Then as I got used to it, yellow spring, same turns.

If that doesn't quite get it, raise the needle a clip.

gmoss said:

That sounds like exactly what I need to do, good advice.

FLT said:

FLT - What difference do u think #8 slide makes to your performance?

Byte

jmikec100 said:

Jmikc100 - What clip setting you have on you JD blue needle?

Byte

Byte The #8 slide really cleaned up the first 1/8 to 1/3 throttle . It runs perfect now with my settings . I'm going to try a #168 main it will pull it i'm sure. If you are having trouble with your first part of your throttle try the slide, you can get one from JD jetting. Good riding