My bike wasn't started for a while now, I did a carb cleanup and replaced the fuelling issue, but now it feels like it doesn't suck air in but the exhaust side works, can this be a valve being stuck? Or a timing chain issue? I don't want to open the engine, it's hard to find the gaskets here
Would be unusual for a spontaneous cam chain issue or stuck valve unless the bike sucked in water before being stopped and was not dried out maybe. Even then, it would be odd!
If you take the air filter out and put your hand over the inlet duct, can you feel air being sucked through your fingers when the engine turns over?
What happened the last time the bike ran?