Originally Posted by ksmailes
I bought a 1993 SC 650. I have read that I should block off the oil pump and pre mix the fuel because the pumps are known to fail. What ratio do I mix the fuel?
I don't know where you read oil pumps fail, but that is a bunch of BS, the oil lines are what fails not the pumps. And they fail due to age or neglect, Loose or cracking lines are to be expected and mantained. Reason being the oil injection isn't just pumping oil in the fuel, it is metering it at the right ratios for the right rpms which could be any from 100:1 at idle and 50:1 at WOT, and any where in between.
So if you pre-mix not only are you going back to the seventies in technology, but you are at 50:1 ALL THE TIME. Which will cause fouled plugs at idle speed, harder to start, produce smoke and pollution, waste oil, foul your carbs and have to lug oil around. I never stop shaking my head at people who just yank out their oil injection before understanding what the problem is and correct it. But to answer your question 50:1 is the premix ratio for most two strokes.
I have owned about 20 or oil injection systems going back to 1980. Not one has ever failed. The majority of them were on Skidoo snowmobiles and operated perfectly in sub zero weather