From:Dave Hennessey
Subject:RE: RE: Old Oil Cans - Harley viscosity numbers Date:Wed Nov 27 10:51:37 2013
Response to:18992

That's what I was looking for - proof that

"75" Medium Heavy = SAE 40
"105" Regular Heavy = SAE 60

We're still not sure of "58", but it probably is SAE 20. Of course, few of us are riding anything when the temperature is below freezing, so it really doesn't matter much.

"58" Special Light = SAE 20

For the transmission, the Lightweight Service Manual says to use "75" Medium Heavy (SAE 40) when the temperatures are 32 degreesF and above.

Some cans say both. H-D never used a 70W oil.