The chain on kart seems to frequently have a tighter and loser condition when rotating axle. By this I mean, while slowly rotating axle, and looking at top side of chain as it rotates, it is tighter, loser, tighter, loser. Common causes?? Staring around at chain, rear sprocket angle, and clutch sprocket axle, I am not convinced all the angles are equal. No laser alignment tools here or other fancy chain alignment tools. Any suggestions? Thank you.