ATC200M engine rebuild. Seeking ideas.

[Social Torture]

I should start by saying that this is a project for a later date. I'm just brainstorming, for now.

I'm planning to do a complete rebuild an engine from a 1984 Honda ATC200M.

Everything in the crankcase seems fine, but the entire top end cannot be saved from an encounter with sludge.

I was considering the idea of using the top end from an ATC200S. Would that improve the performance of the engine?

Since I'm not building a race trike, and I'm not going to pulling anything with it, so I'm planning to replace the stock 11 tooth drive sprocket with a 12 tooth sprocket.

Does anyone else have any ideas that they'd like to share?

Thanks, in advance.

[oldsguru]

I do not believe a 200S is any different than what you have. I just freshened a ATC200 and 200ES. Both builds I used XR200 cams, 10:25 Wiseco pistons and XR200 carbs. Very, very happy. PM if if you would like details on parts sources, etc.