XR125 - very slow initial idle speed

craigs23 · Mr Muscle Joined: 08 Jun 2005 Karma :

Can anyone give a little info before I start poking around my bike?

2,000 mile XR125, based on a CG125 engine. When I first start the bike after being left overnight, or when leaving work, it'll only start with a little choke and absolutely no throttle. Any throttle just kills it. Once the bike has started, it idles very slowly - but doesn't die. It'll allow me to blip the throttle only after a minute or so - any sooner will kill the motor.

It'll then idle fine after a couple of minutes after that.

Just a bit worried as I presume a very low initial idle could damage the engine?

Ariel Badger · Super Spammer Joined: 02 Dec 2006 Karma :

Sounds perfectly ok to me, you could try half a turn on the tickover screw on the carb that will speed it a tad but it may race when hot.
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Acemastr · World Chat Champion Joined: 01 Oct 2008 Karma :

my ybr is similar, except i give it full choke and press the starter, idles slow for a second then begins to pick up
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2017 KTM 350 XC-F - 2014 Yamaha R6 - 2005 Yamaha YZ125
2016 Toyota Tacoma Limited

ash-2009 · Borekit Bruiser Joined: 02 Mar 2009 Karma :

i have the same bike honda xr 125 2004 8k on the clock it does the same thing mate im guna try turning the screw a bit as said above Tops out about 75mph the guy before me took the throttle restricter out of the carb or something

Thom · World Chat Champion Joined: 24 Oct 2007 Karma :

Craigs, was your CG not like this?

The ones ive used have all done exactly the same...

It's natural im sure. aslong as it idles properly once warm, and you can ride it from cold without too much of a problem i see no problem unless it stalls at junctions etc eithout throttle.
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Current Bike: 1996 Yamaha TRX850 (The Japanese-Ducati One).
Previous Bikes: 1990 Honda NSR125 'Rothmans' (The smoking one), 1990 Suzuki GS500e 'Caf? fighter' (The loud one), 1987 Kawasaki GPX400r (The quick one), 1997 XJ600s Diversion (The reliable one), 2000 Kawasaki ER-5 (The spontaneously combustive one)

Gawain · Nitrous Nuisance Joined: 06 Dec 2008 Karma :

Sounds fine maybe try choke for a little longer if it worries you. May help.

ash-2009 · Borekit Bruiser Joined: 02 Mar 2009 Karma :

my xr 125 cuts out when warms up dont kno why any ideas

el_oso · World Chat Champion Joined: 17 May 2008 Karma :

is the choke off?
that bike has a two step choke.
fully on should only start when given a little bit of gas. will start like this in the coldest of weathers. never failed to start the bike for me.
half on - as soon as you start the engine flip it one notch. keeps the engine running a little higher than normal tick over.
full off used when engine is warm
when its cold i usually: start the bike with choke, flip it one notch to half on. put gloves on, put helmet on. flip the choke off. if it still doesn't idle i ride to the end of my road on half choke or as I'm riding along my road and switch it off as I'm riding. by the time i get to the end of my road it idles fine