My shop manual calls for "HD Medium weight" oil for the '81 Ironhead. What does that translate into in terms of today's oils? Straight 30? Some special vintage oil?

It's a stock, mild use, bike.

Thanks!

 

harley 20w50 dino or any other m/c dino oil

 

HD Medium Heavy Oil was SAE 50.

 

Thank you both very much.

 

I run straight 60 wt in my 75.


carl

 

"Most guys" run dino oil, straight 50W for normal temperatures, 60W in extra hot climates. 25W50 in winter.

 

I usually run 20w50 in the winter and straight 60wt in warm/hot weather. This season, I'm trying out some 25w60 I bought - hopefully it will work ok year round, but we'll see when summer rolls around.

 

I meant to say 20W50 in winter.

 

Well...I found straight 50 in a Valvoline race oil which boasts added zinc levels for flat tappet and similar sliding surfaces. Sounded good to me. $6.85/qt. at most auto stores.

 

Straight 50 or 60wt depending on temps, pre evo bikes didn't like multi weight oils. 20-50 will work but the bike run hotter and make a load more engine noise.