Bike won't stay running until warmed up

[kymcofan1]

Hey folks, I posted about this earlier, but I have some updates. My bike is only about 6 months old. I've tried taking it to the dealer for service, but they haven't been very helpful. So anyway, the weather where I'm at has been in the 40's and 50's, and when I try to start my bike in the morning, it'll run a bit rough until it warms up. If I give it throttle while it's cold it'll die, and I have to start it up again. Some days it'll die, and then I can't start it again, even after four or five attempts. I just have to wait until later in the day for the temperature to go up. Now, I've tested the electric choke and it appears to open up after about ten minutes of running. I don't really know what to do, because I'm new to carburetors, and I don't know what to adjust on it to help resolve this. Could this be a case of the bike running too lean? Or, should I raise the idle? After the engine warms up, it runs all day just fine. I'm a competent mechanic, but I've only ever fixed modern cars, so this is different for me. Any help is appreciated, thanks.

[Iahawk]

it'll run a bit rough until it warms up. If I give it throttle while it's cold it'll die, and I have to start it up again. Some days it'll die,

sorry to hear you're having troubles with a new scoot. Since you've already tested your auto bystarter (electric choke) I'd start with a good cleaning of the carb. Sounds to me like the classic clogged pilot jet. Easy to happen to any carb that sits for even a few weeks. Your pilot jet has an internal diameter of .35mm (1/3 of 1 mm) and clogs easily.

If you're not familiar with these carbs just do a youtube search for cleaning GY6 carbs...tons of videos out there. Good luck!

[CROSSBOLT]

Hey folks, I posted about this earlier, but I have some updates. My bike is only about 6 months old. I've tried taking it to the dealer for service, but they haven't been very helpful. So anyway, the weather where I'm at has been in the 40's and 50's, and when I try to start my bike in the morning, it'll run a bit rough until it warms up. If I give it throttle while it's cold it'll die, and I have to start it up again. Some days it'll die, and then I can't start it again, even after four or five attempts. I just have to wait until later in the day for the temperature to go up. Now, I've tested the electric choke and it appears to open up after about ten minutes of running. I don't really know what to do, because I'm new to carburetors, and I don't know what to adjust on it to help resolve this. Could this be a case of the bike running too lean? Or, should I raise the idle? After the engine warms up, it runs all day just fine. I'm a competent mechanic, but I've only ever fixed modern cars, so this is different for me. Any help is appreciated, thanks.

My first Kymco was an Agility 50. It was like my first motorcycle: "cold blodded" was the term for early Hondas. They had manual choke levers and the durn things would not run properly until warmed up! Your "by starter" sounds like it is either overly slow or not working. There are some GY6 and Agility and carburetor genius' here and elswhere who can advise you in honest detail. You see, I cannot recall if the test shows it extends the plunger or retracts it or how much....

Have you a service manual? Manualslib.com could help or cyclepedia might. Please post what you find!

What Iahawk said!

[Iahawk]

Karl, I have to think about the bystarter function, too! I believe it starts out retracted, to allow additional fuel flow, then heats up, extends plunger to cut off the extra fuel to avoid rich running while warm.

I've just had so many instances of my S200 starting, then the slightest crack open of the throttle kills it. Always was a clogged pilot jet. I ended up buying a couple extras to always keep on hand. jetsrus.com is where I find my Keihin jets.

https://jetsrus.com/a_jet_kit_scooter/honda_250_CN250_helix.htm

[Vision]

That sounds normal to me. My bike takes a while to warm up and I get the impression it doesn't like to run in the 40's and below. Once it does warm up (can take over 10 minutes) it rarely will cut off. Maybe a value adjustment in cold weather would help but that seems like a pain.

May try high octane gas or some techron as a test.

[Ruffus]

Yes, bystarter starts retracted. After getting voltage pushes its piston out ca. 10mms.
Also warms up, feelable by hand.
Important this o-ring intact.

[Vision]

I take back my previous message. Yesterday I went for a ride at 45f outside and after warming up the bike ran just fine. I think my previous cold weather issues were due to needing a valve adjustment.

[JJJoseph]

This doesn't sound "6 months old" - it sounds more like a 10 year old machine with a carburetor and electric choke!  New bikes are fuel injected for this very reason. If it's indeed carbureted, this is normal behavior in cold weather.  They have to "warm up" first, perhaps for several minutes, before driving.  FWIW, KYMCO carburetors aren't as well-behaved in cold weather as Keihin carbuetors.  They're easy to swap if you're tired of the KYMCO's cold-weather behavior.