Idle or not Idle?

[steeldust]

A friend of mine sets his idle screw so low it wont idle so he always has to start if he lets go of the throttle.  The reason he does this is because its a race bike thats what he says(stock rm 250 with pipe and silencer).  He couldn't give me a good reason why he won't let it idle.  The only reason I can think of is if he wrecks the bike it wont keep running and hurt the bike or himself.  I know I always get my bike to a low idle.  Any ideas or this guy full of BS?

[gowen]

I'm sure somebody here can answere the question, but mainly cause of surging, when you rev a two stroke, it risks a small surge when returning to idle, so if you let off the throttle after a wide open run, it will surge lightly and if you are flying into a corner for a slide, it will cause it to surge in the corner and really cause issues. So they say.

[kiwikx500]

If you look on the factory spec sheets for the 5 hundie it is set up not to idle from the factory prob for the reasons above

[Arigato]

On a two-stoke, eliminating the idle increases throttle response.  If you're a pro, you'll notice it.  The rest of us will stall.

[KXcam22]

Arigato,
 I gotta ask how on that one. All idle is is a stop that doesn't let the slide bottom all the way.  Shouldn't change throttle response unless they set the air screw differently. Am I missing something?In my pro days I always wanted an idle so you didn't have to restart if you fell off.  Cam.

[gowen]

Arigato,
 I gotta ask how on that one. All idle is is a stop that doesn't let the slide bottom all the way.  Shouldn't change throttle response unless they set the air screw differently. Am I missing something?In my pro days I always wanted an idle so you didn't have to restart if you fell off.  Cam.

Exactly, especially when hot and muddy! There is nothing worse than a muggy hot day in the mud being roosted in the face trying to restart your bike.

I used to race alot on my 250 and always kept an idle. What I don't like is stalling in the air off a 100ft double!!!

[Arigato]

After speaking with several engine tuners I stand corrected. Sort of.   The CR500 (the bike I had before the KX) runs older style PJ Keihin carburator that incorporates the idle adjustment and the choke together.  This makes for a delicate balance between proper idle and flooding the motor with fuel when the throttle is opened up...On KX's with the PWK carb, this is not an issue.  Some mechanics still set the idle to 0 to be sure that the motor does no overrun when going into corners.  Set your idle where you want it, and don't forget the wasabi.

Arigato

[Timbowe]

Burn baby Burn!

[FuriouSly]

I like when a bike idles..  it sucks when you are trying to adjust your goggles or something of that sort and the bike putters out on you.  Think about the races with the 2-strokes and some 4-bangers where the mechanic/riding coach is at the the starting gates and has to keep the bike running for the rider while he is getting ready.  Unless you are seriously into racing and ultimate performance, the idle/no idle is a pretty insignificant power issue I would imagine (but I don't race).

But as far as the idle issue on my bikes?  I like idle.  I just got my KX5 motor/carb back from the motor builder that we all use here in Vegas.  I did a reinforcement mod to my rads in the meantime and should test it on the next trip with a report to follow.  Anyway, I put the bike back together, added fluids, and the bike started on the second kick !  Warmed it up a bit, shut it down and restarted it a few minutes on the first kick.  Now this is not a stock motor anymore.  Head decked with thin squish for higher compression, ported cylinder and intake/exhaust ports. The PWK was ported to about a 41mm with other custom work that is semi-secret to the builder.  If you hold the carb up to the light you can see through on both sides of the slide.  So with that being said, I didn't even adjust the idle screw from the position I sent it off at and the bike selted down into a perfect purr of an idle.  Did I mention that I like idle   

Just some reteric from myself...  Sly

[Danger4u2]

I like idle.

[Gonzo]

I like a relatively high idle on a stroker cuz I'm always paranoid of it dying on me. [had it happen too many times.] That and I've got less of the rev range to cover before I'm in the power.

[FuriouSly]

I still like idle...  yep.

Sly

[eprovenzano]

I too am a fan of bikes that idle.  Nothing is more frustrating than coming down a steep white knuckle hill, trying to maintain some sort of control over a bike with the rear-end wanting to go first, while you've got a death grip on the bars, wondering if your going to avoid the trees, and then bike wants to stall because it won't idle....

Did I mention, I too like bikes that idle...

[Polar-Bus]

Quite a few different opinions on yea or ney on an "idle". My .02, is for MX'ing you do NOT want an idle. When you create an idle, you also create an extended "hang time" in engine rpm's when abruptly decellerating. This causes added "drive" entering corners that is not wanted. Most pros litterally come into a corner so fast, they drag the rear brakes, and many times stall the engine, immediately let the clutch back out, and the drive restarts the engine. No idle creates an immediate, consistant "chop" in rpm's.

[John]

Hey, if that's the (only) definition of a pro; I am defenatly a pro! The number of times I stalled in corners... Most of the time the enginge fires up again using the resident momentum of the rear wheel.

My 125 idles and my 500 don't. This is deliberate due to the case of nasty KX500 kick-backs I have.

I never stall when I ride the 500 on tarmac/Motard..? Could be that I am too busy trying to stay alive?

//John