Good Morning / Afternoon,

I have picked up a non running 72 G7S and have also purchased the Service Manual. I wanted to do a crankcase oil change, flush the gas tank and oil reservoir and fill with new oil and gas.

The operators manual for the crankcase just states either a #30 weight for the crankcase or 10w-30w (North Carolina) and preferably Yamaha Autolube 2-stroke cycle oil.

What do you recommend for modern equivalents? I assume this goes in the crankcase and oil reservoir?

Frank

The gearbox will use standard motorcycle gearbox oil, doesent need to be anything special. yam gearboxes in these things are as strong as it gets. 

Draining the 2stroke tank and refilling with oil you know about is no bad thing. Any normal modern 2t oil will do in these old girls even chain saw oil as long as it doesent say premix only on the bottle. 

Have you worked with 2 strokes at all?