KX125 1985 idle??

[1983_Enduro_YAMI]

G'day all,
I'm new into the 125 two screamers.....dunno much about them....I've got myself a 1985 KX125 and spent a bit of money to get it to run like it should....just finish the tuning of the carby but there is one thing i'm not sure. What's the best rpm for the 125's to idle??? i watched a few clips and they're all idling higher than the 250/500.....

Cheers,
Jacky

[Nathan S]

Don't overthink it. Get the jetting right, and then set the idle so it idles reliably for 30 seconds when the motor is warm. Then go riding.

[1983_Enduro_YAMI]

So you mean set the idle so it idles 30 secs and dies if i don't blip the throttle??

[80-85 husky]

if you cant open the gate and get back on the bike in 30 secs.....

[evo550]

Idle is a personal preference, as long as everything else is set correct (jetting, air screw) then it's up to you. Being a 125, go for 12000 rpm, that way you'll never be able to back off....

[Paulos]

Senor Vandy was of the opinion,and i agree,  that you should set the idle high on a 125 so you're carrying revs a bit more in corners. Its not like you're producing cr500 type horsepower on idle

[Nathan S]

What 85 Husky said about the thirty seconds.
Big or small, race bikes aren't meant to idle away forever - but you want them to idle for a bit so that you can put your goggles on or whatever. My point was more about you shouldn't get upset if it stalls after idling for minutes.

I sort of agree with the Vandy/Paulos train of thought, that a high idle can make a 125 easier to ride in some situations. But it can also make the bike hard to start, and just generally find it irritating.

[1983_Enduro_YAMI]

I have the idle spot on now  .....but here comes another problem....i recently just reaplaced the old oval carby with a new round slide and i'm doing the mid range....It's paint in the arse....i'm stuck on getting the needle right. She's sputtering with the clip at the middle position so i moved up one notch and she's too lean....what should i do???

[80-85 husky]

what mix you using?. you may need to look at another needle and needlejet combo

[tony27]

Possibly keep the needle in the middle spot & try the next size leaner needle jet or go leaner on the needle & richer on the needle jet. Not the most expensive part to replace, certainly quite a lot cheaper than changing the slide for example

[1983_Enduro_YAMI]

I'm using 32:1 semi synthetic....i just put a 2.5 cutaway slide in and she runs heaps better....now it's just the mid range with the needle and needle jet.....I didn't touch the needle because i'm not sure of what's the next size down/up of 6FL52 (stock needle).....i did try to put a leaner needle jet (Q-6) but it seems a bit too lean for her as it was bogging down...I'm located at Western Sydney 

Here is my jetting at the moment

Slide: 2.5
Pilot jet: 27.5
Needle Jet:Q-8 (standard)
Needle: 6FL52-2
Main jet: 290

[Nathan S]

Depending on how lean it is with the needle dropped a clip position, it is possible to get shims that are half a clip thickness.

[evo550]

something else can't be right if it's going from spluttering (rich) to bogging (lean) in one clip movement..

[1983_Enduro_YAMI]

Just a few question here with the 80's KX125's......when i quickly open half of the throttle from idle....how it should sounds normally??? Will the power valve opens up when i snap open half of the throttle?? It sounds pretty crisp but it's not bogging or gurgling when i dropped the needle....still smokin out when i went for a test ride 

[80-85 husky]

your at that point where its tough to diagnose by keystrokes...keep talkin

[shelpi]

watch out for miss diagnosis if it has been idling after coming off choke
crank case dilution comes into play (residue fuel in the crank case)
it needs to be ridden to operational temp, then give it a chance in high revs to clear itself then diagnosis can start, using plug drop technic (speaking of spark plug heat range also comes into play) as well as your own sense of what right, if not on a dyno (ive not used dyno's still got hole shot bikes)
Old school but works