Cold Days and First 5 Mins

[scootertrashrk]

Greetings,

I am working on a 2007 5,600mile Schwinn Collegiate. 139QMB.

So far in the past couple months I have:::

Changed the gas
Changed the oil (10w-40)
Replaced the roller weights with slider weights (6g)
Replaced the belt (Gates Kevlar)
Replaced the air filter
Cleaned the carb
Changed the main jet in the carb from 72 to 75 ( I have 78 80 85 on hand )
Adjusted the valves
NGK Iridium spark plug.
Changed the rear gear oil.
I took out the narrower insert in the airbox. Maybe I should try replacing it?
Noticed I only have 2.0mm on the clutch shoes. Which is the service limit!
Flat land average speed: 33-34mph.

In this 15-35* F weather it has still died on me, only when I come to a stop. (Sure, I might be crazy to ride in these temps, but most times I find it exhilarating  )

 It usually dies only within the first 5mins of riding. It likes to hesitate also during this time. Some times I have to feather it to coax out of a stop. But after 5mins, it runs great. This situation is maybe pointing to the Auto Choke. I suppose I should turn the Idle Stop Screw up and the Idle Air Screw out.

I understand the idle air screw only adjusts the idle, not the air fuel mixture during throttle. Starting with the Idle Jet, then we get into the needle notches (1/4 throttle to 3/4) and proceed to the main jet at full throttle. ...as to what makes the biggest difference compared to where your throttle is at...

The exhaust is cracked at the pipe to muffler, I ordered a new one, should be here next week; which I believe is half my problem BTW! The carb I am looking at, has been the first time I encountered a carb without an accelerator pump...

After all this tinkering, does anyone have experience or suggestions for riding below freezing? 

What's the deal with no accelerator pump? Why would they offer that? It is an unsealed carb.

I am thinking of running a lighter oil for these cold temps, 10w-30 or 5w-30. Synthetic maybe?

Thanks Yall!

[Greg]

The colder it gets, the leaner they run.
Maybe it is your oil.
Normally, I would expect the opposite of your results. with the scooter running better when first started because of the richer mixture.

I know in colder weather, sometimes the scoot will run better/richer if the air intake is restricted more.
Definitely try placing what you took out back in from the airbox. Try taking that part out again when the temps are over 60.

[Fox]

I think you just need to let it run for 5-7 minutes before you take off. The worst thing you can do to an engine is run it hard when it's cold. Keep in mind also that the gear oil doesn't even begin to warm up until you are moving so take it easy the first mile or two til it thins out a little. Check the plug color. If it's really light gray or whitish then try a bigger main jet. You want a brown plug with a black ring on the end of the threads.