Workhorse 350 Robin Rebuild/Rehab Project

[Rocketmp]

Hi All! newbie to the site. Scored this 2000 Workhose with Robin 350cc engine needing a bag of work.

Decided to start with the engine as is smokes an intolerable amount. It belonged to my family so i have some history and know it was run like this for a long time. Now that I have it I want to make it right. Engine tear down complete. I really expected to find damage but so far only scaring on one rod and an EXHAUST VALVE PORT FULL OF CARBON (see pic). What would cause 1/2" of build up??. Ive been suspecting the head being the cause of the smoking since the bottom and top end look good.

I have all rebuild parts and plan to measure internal components and to replace what's needed inside. I believe i have a good rebuildable unit and want to get it right on the 1st shot.

Working on the head today lapping in new valves and somehow cleaning the ports. THROW SOME INFO AND GOOD ADVICE MY WAY.

THANKS!!!