agility bogs down when I twist the acceleration (take off)

[alexmoldovanu]

Hey Guys!
I just bought an agility 50cc and when I twist the acceleration t scooter bogs down and the rpm drops but it will recover in seconds.
during the ride as well the rpm drops and then recovers. The idle is fine, it starts right away, but i have this problem.
i runed some seafoam and replaced the fuel, spark plug, and put new oil. The fuel filter and air filter are clean as well. Valves are adjusted at 0.004 inches.
Please help me with this problem and I am sorry about the writing but my english is not perfect. Also I apologise if I wrote in the wrong section but its my first time when I register on a forum

Everything is stock
6000 miles
Kymco Agility 50cc 2009

thank you!

[zombie]

Welcome to the forum Alex.
Your English is just as good as mine, and I supposedly went to school to learn it.

Open the top cap of your Carb. and pull out the rubber diaphragm, and the needle assembly. First try to pull on the needle, and be sure it is firmly seated. Then look all around the rubber part for tiny tears. They usually tear around the edge so a Light may help.

It could be a few different things but that is where I would start since you have the basics covered.

This just shows the diaphragm, and a few little tips.

[BettinANDlosing]

It could need the carb physically cleaned. Seafoam works decently, but it'll never substitute it for gettin in there and cleaning it by hand.

[MoToFaLcon]

Mine does this too when its around 0-20°f. I always thought it was normal? My a50 has 1300 miles on it btw.

[zombie]

Mine does this too when its around 0-20°f. I always thought it was normal? My a50 has 1300 miles on it btw.

That is normal. The dense cold air leans out the fuel mix. Almost to the same extent as a clogged up carb

[alexmoldovanu]

Wow! I wasn't expecting such a quick reply!
Great community!!
Right! I will check the diaphragm tomorrow. Also today i started the engine and started well from the first time. I noticed though that the exhaust smoke smells like petrol, unburnt petrol. Could be the mixture to rich? I did opened the carburetor but i haven't took out all the parts. Just the big jet in the middle and sprayed carburettor cleaner all over a let to sit overnight.
Tomorrow I will take out the plug and i will let you know what's the colour.
Cheers!

[zombie]

Good plan Alex.

We're all happy to help[ here. Let us know what you find.

Just a thought... If you spray Carb Cleaner down into the main jet, it can dislodge dirt that will jam things up inside the float bowl.
The best thing to do is pull the carb. completely apart, clean all the parts, and re-assemble.

Also try adjusting your smaller Idle Mix screw. Turn it in either direction for the best sounding idle (highest rpm), and compensate for that w/ the Idle Speed screw.

[alexmoldovanu]

Good Evening!

Ok guys, i took out the carburettor and cleaned it entirely. The diaphragm was in very good shape.
    The gasket from the carburettor bowl caused me trouble because was stretched and I had to cut the extra part and I sealed with some gasket sealer (blue colour, resistant to petrol).
    I take out the spark plug and it was black black black!!!
The mixture was to rich I image. I played with the mixture screw as well but God! What a head ache! I think everything is ok now. Its not bogging anymore and I feel the engine strong.
I disabled the choke because I broke the needle when trying to put it back. With the choke on the idle was variable,  going up and down and was dropping in rpm when releasing acceleration. Seems ok now.

  I never had a scooter and I don't know how the idle should sound normally. Is not a constant sound like a car for example, in this scooter engine I hear like a variation in tonality of the sound. Is this normal?

Thank you!

[BettinANDlosing]

How did you disable your choke? If you just took everything out you did the exact opposite, you enabled it pertinently!

[zombie]

The engine should sound as smooth as a car.

You can get a new choke, and gasket for ten/twelve bucks + shipping, or just get a new carb for twenty bucks, and keep yours for parts... 
http://www.ebay.com/itm/50cc-SCOOTER-carb-CARBURETOR-4stroke-chinese-GY6-139QMB-engine-moped-SUNL-/321323101291?pt=Other_Vehicle_Parts&hash=item4ad0596c6b&vxp=mtr

That's what I would do.

The up, and down RPM sounds like a vacuum leak. It will either be from cracks around the intake manifold/carb coupler or in the "O" rimgs under the manifold, and on the spacer on top of the cylinder head.

You can pull these parts off, and head to Ace Hardware/home depot, and match up new "O" rings. If the spacer is cracked or the rubber coupler is cracked post back, and I'll tell you how to fix them, and where to get replacements if needed.

One more thing... DON'T EVER use that Blue RTV crap. It is actually not fuel proof, and it will clog up your carb. The tiny bit that squeezes out will find it's way into your jets.

[alexmoldovanu]

How did you disable your choke? If you just took everything out you did the exact opposite, you enabled it pertinently!

Hello! I just disconnected the cables and left the joke as it is.

[alexmoldovanu]

I sprayed some wd40 around the intake  manifold and as well where the exhaust link with the engine. No change in rpm. But it is very rusty that area... I'm starting to doubt the quality of these scooters.

Now I identified a tapping, rattle noise and i think its from the transmission. I will open that and I will post some updates.
 

[blue]

Check your petcock.I went threw the same thing before and found out thats all it was. The petcock was leting to much gas in and was flooding the carb.

[BettinANDlosing]

Hello! I just disconnected the cables and left the joke as it is.

You have permanently ENABLED your choke!!!!! The resting position of the choke unit (no power) is CHOKE ON!!!! Plug that sh** back in!!!!

[zombie]

B&L is right. The choke is now fully open, and supplying fuel.

This all goes back to something clogged up inside your carb. or like Blue suggests the petcock (in this case) is starving the carb.

Maybe even the screen Filter inside the fuel cell is clogged up.

Start at the beginning, and take it all apart. Drain the tank, and look for rust inside. If it's there I have ways to clean that. Pull out the petcock, and clean the screen. New fuel lines, and filters are less that 5 bucks.

Rebuild or replace the carb... Less than 25 bucks

New air filter, and oil change another 15.00

All in all you have everything new, and if there is still a problem, you have a few years worth of new parts. the problem is still there if it runs on a fully enabled choke. If you're in North America... you still have a few months that it will run as is. Summer will kill you w/ flooding