Winter riding
 

I don't know why but my bike wont work in cold weather. It's in a garage, where its sort of warm, it starts up no problem, BUT, when i take it out it starts idling bad, chokes and dies, then it won't start until I get it inside for some time. I tried riding it and it chokes again, probably bad electronics.

I fitted a new NGK spark plug, but it idles and goes WORSE....I'm confused :hmm:
Anyone else with same problems in the cold?

we need a little more information. What type or brand of bike? Does the carburetor have a manual choke or auto choke. What cc motor? Air cooled or water cooled?

It's a Jonway ST25D, 230cc, manual choke, water cooled.

How is your fuel ?

So being that it is a manual choke that rules out the Auto choke not working. When you say cold, How cold are we talking about? Only thing I can think of so far is that the thermostat is stuck and the engine is not maintaining a proper running temp when in the cold. I'll look into it more and see if I can come up with anything.

anything under 5c, maybe it sucks in too much air somehow? But why in the cold only...

fuel is good, just changed the filter too, i use 95oct.

Check also to see if you have an air leak, like Carb to intake manifold.

If the thermostat is stuck in the open position the motor can't maintain the proper temperature to run with the choke off. Does it run if you put it at half choke? Something else you may want to check is valve clearance. Like Pistolclass stated. Check for air leaks too.

Possibly the radiator is clogged so the water isn't cooling the engine when you drive and the temps go up. When it's idling in your garage it's not gonna get as hot as it is when your riding it.

Definitely sounds like a tuning issue. An air leak would certainly cause this.

Changing the gaskets/seals between carb-intake & intake-block may cure this and should be a quick and inexpensive first step.

Clean or replace both the air / fuel filters if you haven't already.

Add about a tablespoon of gas line antifreeze to the fuel tank, this will not hurt the engine but will clear up any condensation that may have accumulated.

How long is the machine idling before you take it out?
While the carb is off for gasket/seal replacement, check that the choke butterfly and choke cable operate freely.
Please post if the problem is already fixed, also I'd love to see a picture of your machine :)

Regards,
Dak