Keeway RKS 125 STD running issues.

[Paincraft]

Hi all any help would be appreciated.

Just bought a 2019 2nd hand bike and apart from this particular issue it is very well maintained. Passed it MOT just before I bought it.

Just to give some context, when first starting up this morning it was ok but on my way to work i stopped to pick something up for a few minutes and when I returned and tried to start my engine it started ok but after a few secs the engine cut out, I restarted straight away but same thing happened; I noted that the revs remained low and then cut out completely. When I started again I kept the revs up for a minute or 2 and when I let it idle it was back at idling at normal level.

This is not the only time it has happened. So i have tried some things to remedy it but have not yet been successful.

I have checked the spark plug (which looks new) and lead but no issues at the same time I took the air filter out to check that and that was so clean, as if it was very new. While I was checking the air filter I noted a tube from the bottom of the tank, being quite new to my own maintenance on my motorbikes I didn't know what this was. It is quite long I don't know if it is supposed to be very long but when I removed it from where It was tucked in to the side of the bike water came out. After a bit of reading I found this was more than likely the vent hose, which if becomes blocked can cause the symptoms. Before this there was a rush air as if the tank had become pressurised when opening the fuel cap. After purging the vent hose this seemed to have not happened again but still seem to have the original issue.

Any ideas that could be the cause or remedy would be greatly appreciated.
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Tony
My bike Keeway RKS 125cc Std
Dream bike MT07

[Easy-X]

Is this starting problem now happening from cold as well or only once the engine's warmed up?
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Royal Enfield Continental GT 535, Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[Paincraft]

Think it only happens when it's warm can't remember it happening when it has been from a cold start
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Tony
My bike Keeway RKS 125cc Std
Dream bike MT07

[Paincraft]

[url]https://youtu.be/RExR4jgzEsc

Just as a visual this is what happens when it is warm and I have stopped the engine, I had just got home pick something from inside the house and came straight back to start the bike. You may see the fuel gauge flashing at the start I had plenty of fuel just takes a min to register how much when starting some times. Don't think that has anything to do with the problem.[/url]
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Tony
My bike Keeway RKS 125cc Std
Dream bike MT07

[that_impulse_guy]

not so much to go on, but for your own investigative purposes, item 39 here https://www.motor-x.com/oem/c3377v-rks-2 may be enlightening. Temp sensor...if this is giving incorrect readings it'll do what you describe.

Maybe go have a look at it and a further google and see if this helps.
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Gone: Yamaha DT50lc, Suzuki DR500, Suzuki A100, Kawasaki z250ltd, RD350YPVS, Suzuki DR Big, Kawasaki AR125, Kawasaki KMX200, Suzuki GS1000S, Katana 1100, GS550M, Suzuki RGV250
Now: Suzuki GSX400X, Suzuki RF900R, NS400R

[WD Forte]

Could be the temp sensor but
I'd read the fault codes before buying bits for it
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bikers smell of wee

[jeffyjeff]

I think your problem could be solved by adjusting the engine idle speed. There is probably a thumb screw on the throttle body for that purpose.
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History shows again and again how nature points out the folly of men - BOC

[WD Forte]

Keeway is made by Qianjiang Motorcycle one of Chinas largest manufacturers
I believe like a lot of other chinese firms they use the Delphi EFI system or a variant of it.

Reading fault codes should always the first step when trying to fault find on EFI bikes.
It's better, cheaper and faster than swap and hope.

I had a Honda SH125 here a while back which ran but the rider said
lacked a bit of its usual 'power'
A quick test showed it was getting erratic signals from the O2 sensor.

A connector clean and reset got it back to running normally luckily
but if had needed a new sensor, it would not have been a long winded
process
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bikers smell of wee