A 2 stroke race bike, if made to idle, will run on a bit down low since the slide will always be slightly raised.

You want a 2 stroke to be a bit rich off closed throttle and you want it to barely idle. Like you need to blip the throttle every 5 seconds to keep it running.

I ran my 2 strokes w/ idle for a long time and they do work ok like that, but they are snapier and run harder if they don't idle.

If I was offroad riding, I'd make it idle (leaner AS and idle screw). For MX, no idle please.

MX two-strokes arent really supposed to idle

PSD_Sun, on 20 February 2012 - 08:21 AM, said:

So I am not getting old and forgetting how to set up a 2 stroke MX bike?  So a MX 2 stroke that does not idle is not a PITA after all?  Shucks.

Edited by KX290F Pilot, 20 February 2012 - 02:59 PM.

Here's mine.

Seeing those pics makes me want to buy one even more now.  The lowering link looks cool but does it help a lot with rear end being more compliant and hook up better?  Nice bike.

Well I didn't know mx bikes are suppose to run like that my bad. But I absolute love this bike. Hands down best bike I've ever had.

most ktm come from the factory with the idle screw turned out, and you have to adjust them in. That bike should idle no problem

KX290F Pilot, on 20 February 2012 - 09:04 PM, said:

.Yeah it help's a ton!!!Track's better through whoop's and off camber stuff,Shock just feel's better and firmer now.Seem's to hook up better through flat turn's,Kinda hard to explain but $$ well spent in my book!!

What are these guys talking about two-stroke mx bikes arent suppose to idle or are supposed to be rich at idle and barely tick over?????  I can see how misinformation is spread so easily on the net by people who think they know what they are on about. Your bike shold be able to idle easily and not foul a plug. If it isnt there is something going on.

Edited by Stillhavetimeleft, 21 February 2012 - 09:47 AM.

I have a 2012 ktm 250 sx.
The jetting I run is needle N1EH clip 3rd from top. / main jet 160 / pilot 40

Gas is 92 octane with maxima super m at 40:1
I start the bike and it will idle for maybe 3-4 min and I give it a little gas and all is fine.
Never fouled a plug yet in the bike.

Ron.

KX290F Pilot, on 20 February 2012 - 02:59 PM, said:

Or maybe you are getting old and are remembering how to set up a 2 stroke MX bike from the 70's.

Stillhavetimeleft, on 21 February 2012 - 09:47 AM, said:

And you will keep the trend up.  No one said they are not suppose to idle but are setup that way for better performance for MX.  Read the whole thread.  You can make a 2 stroke idle all you want, hell put it up there around 2K RPM for that matter,  all we are stating is it performs better if you set it up to barely hold an idle for a few seconds when at a stop.  MX bike here not backwoods Canada stuff.  KTM sets the SX up this way for that reason.  I cannot speak about all the other 2 stroke things out there but this thread was about a 2012 KTM250SX Motocross bike after all.  Whatever.

timmyp8823, on 21 February 2012 - 10:29 AM, said:

Well I said old not ancient.  Was dirt around back in the 70's?  My 2 stroke days started in the mid 80's.

Lol

tsquare, on 20 February 2012 - 06:37 PM, said:

That is one fine looking piece of machinery!  

Stillhavetimeleft, on 21 February 2012 - 09:47 AM, said:

how about u tell this to Mitch Payton and see what response he gives you.

Edited by KTMrideR146, 23 February 2012 - 12:53 PM.

KTMrideR146, on 23 February 2012 - 12:53 PM, said:

He would say"who cares,4 strokes pay my bills these days". But seriously,I suppose you know him?

timmyp8823, on 23 February 2012 - 10:13 PM, said:

lol i dont kno him personally but the fact of the matter is he would say a 2 stroke jetted fr MX racing is not supposed to idle without givin the bike some "blips" of the throttle

There is some false info all right out there. BUt it's the guys that think that they understand race 2 stroke jetting that are spreading it.

Properly jetted a modern racing 2 stroke will in fact not idle. If it idles, the slide is raised and the engine is inconsistent when you crack the throttle. You want the slide closed and the air to be forced thru the pilot jet instead.

Typically once you lower the idle on your 2 stroke to not idle, you really need to up your pilot jet one size so it's not lean on the bottom. You actually want it a little fluffy/ rich down low for best engine response.

Bikes rarely come like this from the factory because think of all the riders that would be complaining that their new bike doesn't idle. And besides, any race tuner understands this concept.

The other big misconception is that you can run as much 2 stroke oil as you want as long as you jet for it. Also not true. If you don't have a burned clean spot about 1/2 the size of your thumbnail on either side of the piston where the transfer ports come in, then you need less oil. If the piston crown is 100% covered in black, then the engine actually runs hotter.

some oils makes yor piston look black even though they shouldnt be.

iv had my bike close to stock jetting but leaner and have 20-25:1 ratio oil, never seized a piston nor abnormall scratch marks. never had a "Lean" run on my bikes.
the only thing iv noticed is more oil-less snap.
from 32-1 to 25:1, you wont notice anything. but from 25:1 to 20:1, then youll notice it took a bit more snap.