TaoTao ATM50-A1 idling problems By nivanov (Read 3,262 times)

[nivanov]

Hey guys,
There's a fair number of posts about fixing idling problems on TaoTaos, but none of them describe what I'm experiencing, so I decided to post. I have a new 2013 TaoTao ATM50-A1. Right when I bought it, I replaced the spark plug and the CDI module. I rode about 100km on it and then replaced fuel lines and vacuum lines, since I've read that they deteriorate pretty quickly. I think I've had this problem from the start as far as I know, though I haven't tried running with the stock spark plug (hell no) and the stock CDI (I have this one instead: www.amazon.com/gp/product/B008RU3FRA/ref=oh_details_o07_s00_i00?ie=UTF8&psc=1 ). I'm still running on stock oils - will be replacing those soon, and also will be replacing the belt.

My problem is this:
When I start the scooter, it idles at relative high RPMs - not enough for it to start moving on its own with a rider on it, but enough to turn the rear wheel if it's on the center stand. If I let it sit like that for a while, or start driving it, whenever I come to a stop, the scooter will all of a sudden start idling at extremely low RPMs, almost dying. The light dims significantly and if I turn the throttle, the engine dies. I have to be very careful to either not let the RPMs fall low, or turn the throttle VERY slowly to get it to higher RPMs. Currently, I keep turning the throttle up whenever I hear the RPMs go down.
Thing is, after about 10-15 minutes or riding, this problem goes away: when I brake, the scooter drops down to proper idle RPMs.

Is this standard behavior for these scooters to not idle well while cold? Any advice would be greatly appreciated!

EDIT: My carbs are stock. There's an idling screw that I played around with in the beginning, but the air-fuel mixture screw is covered up with a plate. Could it be that it's running lean, and it's harder for it to idle when it's cold because of that?

[Alleyoop]

You need to either drill out the PLUG on the fuel ratio mixture or get an aftermarket carb that does not come with the fuel ratio mixture plugged. All you need is to adjust the carbs fuel ratio mixture.
The CDI that you bought has a fixed advanced timing which makes them idle a little higher because the spark plug is firing sooner.

Also the ENRICHER is feeding it extra fuel when starting the motor cold and it should shut off the extra fuel within 3-5 minutes.


Now if you go and drill out the plug the screw behind the plug may or may not have a slot to fit a screwdriver on it. The latter carbs they did not put a slot on the screw. But you can work on it and unscrew it out and then manually put a slot on the screw.
Alleyoop

[nivanov]

Thanks for your reply. So does it sound to you like it's a problem of the bike running too lean? I've read about getting access to the mixture screw, but if it's not an issue of the mixture ratio, I'd rather not mess with the carb. I'm also not sure why this problem goes away after riding for 10 minutes or so.

Thanks!

[Alleyoop]

Well that is up to you but sooner or later you will have to mess with the Fuel Ratio Mixture they set them really LEAN to pass emssions. It is going to get worse rather than better. You do not want to run lean because serious damage can happen to the motor, as they say pay me now or pay me a lot more later.
Alleyoop

[mikey34]

It could also be a valve gap issue. I say that because it gets better after 10-15mins. To me, it sounds like your valves are warming up and start opening wider.

I know after I adjusted my valve, I gained speed, power, better idle, quicker throttle response.
I think its a good idea to at least check to see what gap they are, pick up a feeler gauge and check it. Can't hurt.

Good luck!

[nivanov]

Thanks for your response mikey! As Alleyoop suggested, I've adjusted the mixture and that seemed to fix the problem. I drilled out the brass plug over the mixture screw, but the screw head was very weird shape - it was round on one side and flat on the other - I guess that's supposed to prevent people from tampering with them. I used a roach clip (a thin alligator clip might do the trick as well) to unscrew it, then took a dremel to it and put a slot on it so i can easily adjust it with a flathead screwdriver. After messing around with the idle screw and the newly-accessible mixture screw, it seems to work a lot better. It doesn't go into the super-low RPMs it used to and I don't stall it when I try to accelerate when it's cold. It still idles a bit better warm, but hey, it was less than $700!

Thanks for all your help guys!

[Alleyoop]

FANTASTIC!! Good job my man, now if you took it to a scooter shop they would stick you with a new carb and a nice hefty bill.
Alleyoop

[bobthetechguy]

And scooter shops like to charge about 75 bucks an hour for shop labor.

[nivanov]

I bought this scooter specifically to mess around with it and learn to work with motorized vehicles. I figured that most likely, if I mess up a part, I can just buy a new one and replace it, or if somehow I mess up the whole scooter... well, it's $700!

I have a general question for you guys - how do I determine if my scooter is running too lean or too rich?

[Alleyoop]

The motor will usually tell you if something is not right. It will make certain sounds that will tell you what it needs or what is wrong.
Here are the sounds a motor will make when something is not right.
Alleyoop

www.scooterdoc.proboards.com/index.cgi?board=intake&action=display&thread=8628