Cutting out at idle

no year told, nor when it last run perfect not told
same answer for 100 years on any otto cycle gas engine made car or motorcycle or scooter.
same., and drives fast too, full power work but idle fails.

well , idle is too rich, as are all carbs this old and never serviced.
when it stalls i bet spark tip is wet with fuel or carbon fouled.

or bad fuel. or caused by bad fuel endless for 100years
ive cleaned like 1000s of carbs in 50+ years. endless. me.
it's only a 150cc engine, and tiny carb. my CB750s old and new.
both had 4 carbs and are tricky and must be synchronized
but your's is a pussyycatt. 1 carb small
causes all.
the float needle is bad causing too high float level.
the jets are bad or wrong or dirty. there may be 2 jets one is idle and bad. but most time not 2, just 1 jet and 1 needle.
the needle can be bad , most are this old and bottom of needle is idle section OF NEEDLE and all worn out and now super rich at idLE SPEED
the air paths inside the body of carb must not be clogged
all tiny air paths. checked and cleaned fully.
that is all I can think off off hand.
my guess is bike is super old.
is bike real honda or this trashy china clones of 80 honda.
no year told nor photo of it so we can ahhhh that BIKE,
THE TANK VIEW IS OMG EASY TO ID.

NOT TOLD , FAILS IDLE HOT AND COLD ENGINE BOTH.
Using throttle grip hold RPM up a tad to get it hot first and see if idle reall fails hot.
first 150cc bike owned ever,?yes
the learn this.
we start with mild choke cold and back it off bit by bit until warm.
the chock has a fast idle features that must not be broken.
back it off slowly for 5 mins. then idle works
some have idle mixture screw on the side or is fast cold idle screw.
the cables are not for idle. ever and are set loose side
a stop screw idle and maybe mixtures idle. tool
depends on year not told if honda mikuni made.

Hi Roderick:
I'm not familiar with your engine configuration, but on some of the older bikes, vibration eventually can cause a wire to break in the coil. When the engine is cold, the wires make contact and it runs, but as soon as it gets hot, the connection is broken or compromised and the spark quits or drives you crazy.
Since your bike runs when cold and quits when hot, I'd be looking for electrical rather than fuel problems.
Hope this helps.

Common idleing is corrected by points on many blades. Clean the points and reset distributor and timing. Check loose covers for water seapage and seal when recommended by the mnfctr.

Sounds like a fuel cut out switch!

minha yz426f quando vou de terceira marcha devagar mas quando eu acelero a fundo ela engasga , mas ? so de terceira marcha de rewsto nao faz isso

ok if you are runing on the fwy and let go the gas pedal the only air is coming in from the idle valve and on neutral the same ting what about wen you start the car first the rpm is high 1400 or 1500 then going down wen it get hot that car had two valves the cold idle valve and electric valve the electric valve control the regular idle wen the car is hot after the cold valve is closed

run a can of Seaforam in the tank..purchase from Autozone put in 1/3 to two gallons gas drive it around for at least 10 miles to insure it cleans out the whole carb system.if that doesnt work, check all carb hose fittings when bike is at idle spray some Chemtool B-12 ( also at Autozone) around the carb hoses and manifolds..if idle increses thats your problem. Caution: chemtool is very toxic wear gloves and a mask.

Either idle set to low or idle circuit is clogged in carb.

ive got a wre 125 husky n its fine when cold try and hot ticking over try adjusting the idling screw on carb when started not sure how many turns from the in position