Idle Speed

[njagility]

My Agility 50 starts fine and idles at around 2000 rpm as per the specifications. However after it's warmed up the idle speed raises to around 3000 to 3200 rpm. It's also a little slow to drop to that 3000 rpm.

If I adjust the idle of the warmed up bike to 2000 rpm it idles fine and runs fine, but when it's cooled down and I restart it starts OK with a little throttle applied, but it dies when I let go of the throttle (idle speed is too low). To get it to idle at 2000 rpm I have to adjust the idle speed back to 2000 rpm (idle screw all the way in).

Any ideas what might be wrong? I'm not 100% familiar with how the automatic "choke" system (auto bystarter) is supposed to work, so could there be a problem with that. Starting isn't an issue so I assume it's enriching the mixture OK, but maybe it's not increasing the idle speed like it should (presuming it should)?

[tortoise]

not 100% familiar with how the automatic "choke" system (auto bystarter) is supposed to work

YouTube

[BettinANDlosing]

Have you adjusted the fuel mixture?

[njagility]

That's what I'm trying to do now. The idle mixture adjustment screw was sealed with a metal cap. I've finally removed it, but the adjustment screw looks like it needs a special tool to turn it. The head isn't a slot, it seems to be a raised metal square which will need a very small tool with a square hole in it to turn it. There's no room to try to get a pair of needle nosed pliers in there.

I guess this is done to stop you messing with it (for emissions control purposes). I've had the same thing on a motorcycle where the mixture screw was sealed off to prevent tampering. That one didn't need a special tool to turn it though.

It may be a standard tamper proof screw, but since I can't find my tamper proof bit set at the moment I can't tell. When I find it I'll try the adjustment!

[BettinANDlosing]

It is a fairly standard "D" tamper screw. Otherwise burst out the dremell and cut a slot in it. I've had bikes factory set from 0 turns all the way to 5 turns, they guess and seal it up.

[blue]

I take it its a used scoot.because thats not a stock carb.anyways make sure carb is clean if its not sealed.other wise you may need new carb.

[BettinANDlosing]

I take it its a used scoot.because thats not a stock carb.anyways make sure carb is clean if its not sealed.other wise you may need new carb.

The agility came with the fuel mixture screw covered after a certain year.

[njagility]

It's stock with the OEM carb as far as I know. The EPA got stricter as time went by so I assume at some point they required the mixture screw to be sealed off so owners couldn't easily mess with it.

Found my tamper proof bit set but it doesn't have any suitable bits, just torx, hex, modified phillips (3 and 4 vane) and spanner types. I'll have to look for the right bit or make something up.

[BettinANDlosing]

Another option, drill a small hole and use a small torx to turn the mixture.

[njagility]

I'll come up with something I'm sure. It will be a month or so before I can try though since I'm off on a trip now. I'll followup on this post when I make more progress.

[blue]

I would just look for a 20 mm carb thats not sealed.so you can get to the inside at a later time.

[njagility]

It's not sealed now! The seal is just a metal cap over the mixture screw. To remove it you drill a small hole on it, then pull it out using a self tapping screw in the hole. Comes out fairly easily. The OEM Kymco carb is probably better quality than 90% of the Chinese made aftermarket carbs so I don't really see a need to replace it. Without making other modifications (air filter, exhaust etc.) I wouldn't expect a 20mm carb would make much performance difference, but if it would I'd be interested to hear other's experience.

[The moped learner]

Does it leak gas out the carb?