There were some other tricks, I've forgotten much of it. You probably know about the 2nd/3rd gear exchange to improve the ratio differentials. We did something to the centrifugal cam weights to alter the advance curve, but it's a distant memory. And a copper head gasket is recommended, since it's more durable and can be reused many times. There's a fellow on ebay who custom makes them if you send him a pattern: http://cgi.ebay.com/ebaymotors/YAMAHA-6 ... enameZWDVW 
    --Randall
			
			
									
									
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Latest Registry Entry
                        1965 Honda CP77 — Ulsan Metro City, Rep. Korea
                        Restored with original parts — Owner: J. Doe