Decelerating backfire, gas smell

[harmsworthj]

Kymco Agility 50 2013 7500km. Stock everything.
Noticed the backfiring after decelerating soon after purchase but it only did it every couple days. Bike also had a hard time staying running at idle until warming up, startup and idle always accompanied by gas smell. Adjusted the valves per service manual instructions. No change. Thought maybe didn't do valves right so did them again. No change. No three weeks later the backfiring is happening quite often, and I can feel definite lack of power.
Removed air filter and ran to see if that was causing a rich mix but no change.
Ideas?

[blue]

Clean the carb. or just get a new one.I most likely would just get a new one unless the one you have looks worth keeping...........Any gy6 carb will work good I do it all the time they are cheap and easy to find at any scooter shop.

[wordslinger]

Welcome to the forum, harmsworthj!

..Check all of the vacuum lines, it's possible one is loose..

..to go out on a limb, if you bought it new, maybe it's still under warranty??

..if so, take it in!!

[blue]

Welcome to the forum, harmsworthj!

..Check all of the vacuum lines, it's possibly one is loose..

..to go out on a limb, if you bought it new, maybe it's still under warranty??

..if so, take it in!!

Ya do what word says frist then check the carb any air leak will make a scoot back fire.

[wordslinger]

..well, it's just that the 4t is a slave to vacuum..

..especially the emissions circuits...

[harmsworthj]

Thanks guys i will look into vacuum lines. Any chance a beat up exhaust gasket (from doing valves) would hurt it?
Also, should i resist the urge to mess with pilot screw?

[The moped learner]

I had the same problems did you buy it off the show floor?

[mrbios]

Start with the carb.  Valves get blamed for everything and cause nothing.  I adjusted my valves way beyond the schedule at 8K miles (13K Kilometers).  I did it because it was past due.  However, there was zero change.  Same performance, same mpg, no backfiring - in short all the things people think valves adjustments will fix or cause were non-existent. 

The gas you smell at idle - does that smell like fresh gas or too much gas going in the motor and coming out the exhaust?

If it smells like fresh gas - there is a leak somewhere.

Check the idle mixture:  turn the screw in 1/2 turn at a time and count the turns until the screw lightly stops.  Then back it out.  Should be about 2 turns.  If there are no leaks consider checking and recording the jet sizes.  Previous owner might have messed with the jets.

I'm not against replacing the carb but considering that the scooter is basically new with low miles it should not be clogged or need to be replaced.

Report back to the forum.