A few years ago I interviewed the Tanaka rep for an internet magazine. I'm not sure if it's acceptable to post the link to that article/site, so if you want to read, pm me and I'll send you the link. Tanaka is one of the oldest engine manufacturers in Japan, and is of the Highest quality standards, they were also the first to meet C.A.R.B. emission standards... Their original bike motor kits (Sears free spirit, Tas Spitz, Bike-Bug, and Little Devil brand names) are still plentiful and a high percentage are still running today.
Rif