Hey all, new user, look what I found in the back of my truck. Need some advice.

[oznerol]

As long as there's no energy-conserving symbol on the container, you're good to go. I think it goes from 10W40 to 20W50 - oils in this range (car or truck oil) don't have that energy-conserving symbol. I just changed my oil in my bike with 20W50 Castrol, it was on sale for $18 for a 5 liter jug. So far, so good...didn't feel any clutch slip yet. It actually runs quieter. By the end of the summer, I plan to get the oil analyzed and see how well it performed, and report back here with the results.

[J-man]

From JASO oil Specifications:

4T specifications

Modern passenger car engine oils contain more and more friction modifiers. While this is the good thing for those segments (reduces wear and fuel consumption) it's bad for the motorcycles. At least for those motorcycles which use engine oil to lubricate their transmission and wet clutch. JASO introduced the MA and MB specification to distinguish between friction modified and non friction modified engine oils. Most four-stroke motorcycles with wet clutches need a JASO MA oil.

JASO MA
    Japanese standard for special oil which can be used in 4-stroke motorcycle engine with one oil system for engine, gearbox and wet clutch system. Fluid is non-friction modified.
JASO MB
    MB grade oils are classified as the lowest friction oils among motorcycle four-cycle oils. Not to be used where a JASO MA grade oil is required.

More about MA and MB --> JASO MA and JASO MB classifications

Both Mk1 and Mk2 manuals asks for: JASO T 903 standard: MA
Meaning no friction modifiers.
How much this all means in practice, I have no idea but would follow MA (or MA1 or MA2) directive for all my future bike oil.

[Capnvini]

Welcome. Sounds like you got a nice bike. I'm out on Vancouver Island, drop by.
What happened to the old Honda 750?
Enjoy
Vince