R65 1981 Gear oil

[NorR65]

I have already read a lot about which gear oil to use in this forum.
But I am not sure what to use. What do you use?
I use a gl5 80-90W mineral oil. May be I should use a synthetic oil because I have a neutral if I change gear without giving a little throttle before down changing, from 3 to 2. This is after at least 90.000 km.

[montmil]

You will be fine utilizing in your transmission a known brand SAE 80W/90 Hypoid gear oil that carries the API (American Petroleum Institute) rating of GL-5. This is what keeps the gearboxes happy in my '81 and '83 R65s.

As to using a synthetic gear oil, your tranny oil seals may begin to leak with the thinner and slicker lubricant. Some Airhead riders have experienced this with the older OEM seals. The leaks disappear after returning to a dino oil. YMMV.

Your shifting scenario is not uncommon with the Airhead gearbox and really may not indicate a lubricant nor mechanical problem. Correctly timing the down shift, full shift lever throw, plus matching gearbox shaft speeds, gear engagement dogs, engine and road speeds, needs a nicely trained left toe.
Tis a beautiful thing when it all comes together.

  

[NorR65]

I know what you mean. When the weather is nice, the sun is shining, roads are empty and gearshifts are perfect. That's a good ride. I guess practice make perfect.
May be I shall try a different brand of gear oil next time.

[Bob_Roller]

Personally, I wouldn't get too carried away with oil selection, these are not finicky machines .

A quality lubricant changed regularly, is all you need .

[Justin B.]

I "feel" my shifting is better/smoother with the 85w140 synthetic in the transmission.  I put the regular 75w90 synthetic in the final and driveshaft carrier.