I also think the engine is original. The only thing you need to consider when buying parts is the cam chain adjuster. Yours is the manually adjusted type. So you would want to use a K3 Z50 parts fiche when you're ordering engine parts. The first TL bracket mount I posted above is for a early K1. I goofed that. You can tell by what's left of yours that it was NOT the K1 type. The 2nd link I posted would ship from Australia. So the 2 parts end up being close in price when you figure in shipping.