Bike won't start! Help!

[Katsterrr]

Hey guys. Please help!
I'm having problems with my kymco agility125. I was driving home from work the other day and noticed that if I would have stopped revving, the bike would have cut out. Managed to get home but as I pulled into my drive the bike just cut of. Wouldn't start back up. And the noise when trying to electric start seemed a little higher pitched.
The bike has a new battery. Spark plug has been changed. Air filter clean. Fresh oil change.
If I hold the clutch back about a 1/4 of the way I can get the bike started (eventually) but again will just cut out if I do not continue to rev. There seems to be a delay when I rev to when the bike actually moves.
Any advice guys? It's really frustrating!

[Mr. Paul]

Hey Katsterr. First thing I would check is for a vacuum leak somewhere. Check the vacuum hoses, intake boot,  and the carb adjustment screw and make sure it didn't back out. Simple things first.

[Katsterrr]

Had a fiddle with the idle while the bike was running and made no difference to the problem.
How do I go about checking these other things you've mentioned?

[Mr. Paul]

First visually inspect to make sure all the lines are connected to their source. An old shade tree mechanic trick is to get some carb cleaner and spray the lines in short, directed bursts, paying particular attention to the ends. Also spray where the intake boot meets the intake. If there is a leak, the cleaner will be sucked into to the system and you will notice a change in idle. Do be careful though, obviously carb cleaner is flammable. Do not spray near the spark plug or the exhaust. There are youtube vids on this if you need further instructions. As far as your mixture screw, just check to make sure it hasn't backed out.