Began reconditioning our family’s 86 Trx200SX after it sat in a barn for over 15 years. It was 10 years old when we got it and it ran well but started to burn oil when it got parked in the barn.
I overhauled the carb first and started it and it began blowing smoke very bad and could not get it to run very smoothly by making carb adjustments.
I pulled the head and cylinder to inspect valves, piston, rings, and cylinder wall. I checked the timing marks on the valve chain sprocket before I removed it and it was 2 teeth off of being level with the top of the cylinder head (probably the cause of the engine not running smooth)Lots of carbon on piston head and valves and the valve seals were hard. I cleaned and polished the valves, replaced the valve seals, o-rings and gaskets. The piston and rings looked to be in good shape so I just cleaned the carbon off the piston head. After putting it all back together I started it up and it was running much smoother but after about 45 seconds it began smoking extremely bad again. Probably going to replace the piston rings and maybe the piston. Just wondering if there’s anything else that could cause this engine to burn oil this bad? Any suggestions would be appreciated.