No, I mean the engine valves: Exhaust and intake calls, if either is left open, the compression necessary to start the engine start-up is lost.
Another thing: After starting it and not igniting the spark plug it comes out dry or wet, if it goes dry the problem is carburetor, if it comes out wet almost certainly the valves are.
It comes out dry, buy a carburetor cleaner and apply it and the motorcycle started (that was yesterday)
today early in the morning he didn't want to turn on again until he applied the carburetor cleaner again
Now my question is what has to be done to the carburetor?
Disassemble and clean it, check that at the base of the carburetor it has a screw that does not come out, it is like a stopcock with loosening it a couple of turns it starts to come out of gasoline, verify that it comes out of gasoline, if it does not come out it is because the outlet key of the tank or the entrance to the carburetor, if the low chicler is covered, that is, where it passes gasoline for the start and the idle if you have some mechanical knowledge you can watch some videos disassemble and clean the carburetor or make it a light cleaning of only the chicler goes down because the high one never gets covered.
I finish in comment I tear you off because the cleaner has solvents that work as if it were gasoline.
If you do not have knowledge but want to clean see many videos and surely you will, you can find them and see the videos of morea in their sauce is a renowned mechanic and journalist. Greetings and comment on how your problem continues.