The service manuals for many Japanese motrocycles specify 90W for the rear drive units of shaft drive motorcycles.
This straight weight gear oil has drifted into the past and is virtually not available on the shelves of local automotive supply stores. Multi-grades cover the shelves, most common is 75W-90.
I have seen no authoritative recommendation from the oil companies saying I can use 75W-90 in place of straight weight 90 and the motorcycle companies are no help.
Is there an authoritative resource that compares 90W to 75W-90 and recommends the switch to 75-90 vs. straight 90 weight?
Dan
This straight weight gear oil has drifted into the past and is virtually not available on the shelves of local automotive supply stores. Multi-grades cover the shelves, most common is 75W-90.
I have seen no authoritative recommendation from the oil companies saying I can use 75W-90 in place of straight weight 90 and the motorcycle companies are no help.
Is there an authoritative resource that compares 90W to 75W-90 and recommends the switch to 75-90 vs. straight 90 weight?
Dan