YBR 125 Idling at 6K RPM and Won't Run Without Choke Open?

[tterminus]

Hi all.

Still messing around with my basket case bike. Decided to try and change the oil yesterday, dragged out of the shed and started her up but needed to leave the choke open otherwise the RPM dropped then the engine would cut out.

Also the RPM built-up over time, eventually hitting 6K RPM after 8 minutes of running, this is on idle, no throttle.

So first the inability to run without choke open, is that likely to be the carburetor? If so, considering I'm mechanical of mind with little practise, what would my chances be of servicing it? Any tips or pointers?

Second, what RPM should the engine idle at? Also any pointers where the adjustment is on the engine?

Cheers.

[Alpha-9]

Check and clean airfilter and reoil it
Check breathers and pipes are clear

Should idle at like 1600 rpm tops without choke
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Fzr-600 1999

[unitynotsocri...]

and check the carb cables , brass jets (are there any tiny o ring washers missing ?Check against spec dioagrams)

Thorough carb check , float height

and check ignition timing.
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nearly a normal tax paying tosser.......with ferrileness suzi100,cg125,cb125scb100n,cb175,cd100,cj250t,kh250,c15,125 bantam,super 6,rickman gs750,xt500,250rs,dt175,lifan125,dolomite1850,metro,Morris220ld,morrisfg,leyland princess,range rover,corsa,vw camper .now struggling with legs. MORE ORDER = MORE CHAOS

[Andyk]

my bike did a simlar thing wouldn't idle without choke etc... took it into a local garage for a full service and then checked the valve clearances and re setup the carb and all worked ok. Previous garage had apparently done the carb setup so might be worth checking clearances?

[YBR Ric]

If you need choke to richen it up just to get it to run, that would indicate it's far too weak.
On the assumption that the carb internals are still intact,and the carb slide is sitting on the bottom of the venturi, this would usually indicate an air leak.

Check the intake manifold for splits and gaps and wiggle the carb around with the engine running before the revs rise too much and see if things change.

[unitynotsocri...]

check the needle in the carb slide is on the right notch and that the slide and spring move freely . many people raise the jet so check its all standard .
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nearly a normal tax paying tosser.......with ferrileness suzi100,cg125,cb125scb100n,cb175,cd100,cj250t,kh250,c15,125 bantam,super 6,rickman gs750,xt500,250rs,dt175,lifan125,dolomite1850,metro,Morris220ld,morrisfg,leyland princess,range rover,corsa,vw camper .now struggling with legs. MORE ORDER = MORE CHAOS

[Timmeh]

i bet you 5 ponds the pilot jet is blocked.
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GSXR400 x2 | '94 RVF400 | '93 TZR125 4DL (again)
20:22:30 BLUEX5: i would love to be forced to undergo a**l plugging with different sizes
20:48:18 Temeluchus: comp you hunk of smouldering homos3x you

[YBR Ric]

I'll take mine stocked with Koi