Hey guys,
have a 03 kdx 200 in the shed, been there for quite some time not running and that’s where my problem lies

cant seem to find the problem, I will be riding then all of a sudden cuts out, I changed fuel redid all the lines and carborator but still problem, others say it’s not fuel. I pulled off the ecu (black box under seat) and it had rock like substance on the bottom just for added information.
need some help as I would love to get back into riding again!