20W 50 CF4 on 1970 Royal Enfield iron barrel

[ZeeOSix]

That's giving some confidence to try out Shell Rimula (Indian equivalent of Rotella) or Mobil Delvac. Both come in 15w40 ratings. In addition to that, the workshop manual published by Pete Snidal, suggests getting 40 weight if the conditions doesn't get extremely hot.

How hot are you talking about there in India?

 

[Robin Raja Sekaran]

How hot are you talking about there in India?

On Average, the temperatures vary between 22C (72F) and 32C (90F). And 34C (93.2F) being recorded high in summer.

 

[CleanSump]

Nice looking bike! You should be fine with the HDEOs. I miss adjusting the pushrods, ha ha.
Here's to leisurely rides on twisty country lanes and that thump, thump, thump echoing off the buildings in town!!!

 

[Robin Raja Sekaran]

Nice looking bike! You should be fine with the HDEOs.

Thanks for the advice. I made up my mind to get a 15w40 HDEO. Will have to hunt the thickest in 15w40 HDEO category since 15w50 or 20w50 aren't available.

I miss adjusting the pushrods, ha ha.

Ha ha.. yeah!! Some claim it should be adjusted when the engine is warm. Some say it should be done while its cold. Point is getting it just right - Not too tight, not too loose.

Here's to leisurely rides on twisty country lanes and that thump, thump, thump echoing off the buildings in town!!!

Like you said, its best at low rpm cruising through country roads than highways.