Another new guy...'78 750K oil question

[Ohhbob]

Great forum - glad I found it.  Haven't been on a bike for quite a few years, but I quess you might call it mid-life crisis?  It was either the bike, and old Mustang, or a new girlfriend.  The wife opted for the bike.
I just got a '78 750K that's in pretty good shape - only 18K miles.  I plan to fix-er-up, sync the carbs,  replace rubber parts, etc.  A friend told me SAE oil specs have changed quite a bit since '78 and instead of the recommended 10W-40, I should use a 20W-50.  Thoughts???

Thanks,

Ohhbob

[ohara]

this may sound odd, but i would run and do in mine 15w40 mobil delvac or rotella.  the deisel oil stands up to the shear forces of the trans better, and contains none of the friction modifiers for newer gasoline engines and fuel economy.  i use it in mine and have been very sastified.

[zzster]

Hi:  With the low mileage your bike has I would stick with the recommendation 10w40 but use motocycle oil only.  Buy the Honda brand and you know it will be right.  It costs a little more but who cares, its your engine and tranny we're talking about.
zzster

[snowfighter]

the recommended oil is 10w40, but the other guy has a good point about diesel engine oil having more shear resistance than conventional motor oils. I would stick withthe manufacturers recomendations. Remember any lube is better than no lube at all. check that oil level often.

[machine head]

ive ussed 20w50 in ones iv had and have with no problems but to each there own.

[rm56-2]

Valvoline 10-40 year round. If you plan on beating your engine to death use 20-50w. The higher viscosity oils are good for racing. Penzoil is full of wax. The synthetics were not designed to be used in a 35 year old bike were they? There is a Honda 750 forum out of Europe where some of those people have over 300,000 miles on their bikes. Might be interesting to ask them what they burn?

rm