no vacuum please help!

No compression? Head nuts loose?

No "vacuum" could mean what we call an air leak...do a search for air leak.

I think you have to start at the most common problems and work your way through. I have no idea what the guy is talking about as far as vacuum goes.
If it were me, I'd make sure that the wires are hooked up properly. You need to tell us things like how the kill switch wired up. Many members, including myself have spent hours figuring out that it was just a stupid wiring or switch problem.
The spark plugs that come with the kits are not the best and a spark plug can fail when under compression, you should try another one.
Are you giving it choke and 'tickling the carb" with that button on the left side of the carb? Is this a new kit? Need more info!

He didn't just pull the plug wire and let it spark away? This equals destroyed cdi.

Does it have a fuel oil mix in the tank?

Is the proper amount of fuel oil mix being delivered to the engine?

Find a long down hill run.
open the petcock , on the bottom of the fuel tank ---lever straight down.
Push the tickler button located on the left top of the carb..
push it down gently a couple of times.

Choke lever located on the right of the carb .
place it halfway between up and down.. in the middle.

On the top of that long downhill run .
start peddaling with the clutch pulled in . No gas leave the throttle alone.
When you are going faster than walking speed pop the clutch and keep peddaling until it starts.


Just a thought pull the air cleaner and look in he carb while twisting the throttle does the slide move up and down

try a ngk b6hs plug

Most likely it is an air leak at the carb intake.... Make sure you have either used a sealant or an "0" ring at the bottom of the connection... That is by far the most common problem if it has spark and gas....

no vacuum might mean the clutch is slipping= no piston movement = no vacuum. can you hear the piston pumping as you try to pedal start it?
Norman