1975 Yamaha MX175 oil-gas confusion

Hi All, 

New here and new to vintage Yamaha 2-strokes. Hoping for some sage advice on how to oil and gas my newly acquired 1975 MX175. The manual seems to suggest using a gas-oil mix (see attached) even if the Autolube pump is running??? So, does this mean I use a gas-oil mix in the gas tank and injection oil in the Autolube tank?

For the '78 DT175 also pictured, my understanding is straight gas in the gas tank and injection oil in the Autolube tank, but the manual for the MX175 seems to imply something different. 

Would also welcome recommendations on what gear oil to use for these bikes. I'm planning to use Yamalube 2S in the Autolube tanks. 

Any advice would be appreciated!!




The autolube, assuming it is adjusted properly, is all you need to do. Some that run flat out on a high way have added some extra oil to the fuel tank but that is not needed. Autolube bases flow rate on throttle position and engine RPM.

Stock from Yamaha, the autolube pumps were set to run a lot of oil so brand new owners did not sieze the engine. During the first 600 mile service, one of the tasks was to reset the pump to spec. This eliminnated spooge/smoking and nearly halved the oil consumption. Thing is, few owners ever brought these bikes in to the dealer for that service so the pumps never got reset.

Setting them entails adjustment of the throttle cables and maesuring the pump stroke. The stroke is changed with bras shims. You measure the stroke, and add or subtract shims to get the  stroke into spec. Properly set up, the system cannot be beat.

The few I've had I disconnected and mixed my own gas out of fear of what if it failed! That said I have no ideal the reliability of the pump system.

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