Hi my name is Chris, I just got back my 80cc gas powered bike. It ran fine when I last had it but sat for a year. I drained the tank, replaced fuel lines and filter. Lubed chains and cables, as well as checked the spark plug. It fires up fine and runs but there's a knocking in the engine and after a few moments of riding the chain wants to temporarily seize up. Any help would be greatly appreciated as this is my first and I want to get knowledgeable and capable of repairing it. It's my main means of transportation rn in the small town I live in. Thank you in advance for letting me join and any and all assistance to making this a dependable build.