My son has a Coolster 125 that my father in law gave him a year and half ago. I think I just diagnosed a bad starter solenoid but once I got it running I was reminded of another issue. There seems to be a terrible racket coming from somewhere down near the engine when it's running. I've changed the oil before and it the thing only has about 10 hours total run time on it. Is there any panels or covers I can pull off to see if there is in fact something broken and rattling around? He's ten and though I told him how to change it from F/R/N gingerly it went in one ear and out the other. I'm afraid something may have chipped off in the transmission and could get worse or break something else. Thanks for any feedback or insight!

 

If you can find where the noise is coming from it would be a start. A screwdriver tip on engine case, handle in your ear, can help. Move the tip to different places on the engine to find out when the noise is loudest. Doesn't always work, but it could be camshaft, cam chain, piston slap, crankshaft, clutch or gearbox, unless you can narrow it a bit.