For many years I have used Castrol 1 power racing fully synthetic oil in the Monster and have sometimes wondered if I could do better?
Looking for a suitable oil to use in the old Commando, I have come across an exhaustive test on many oils by Jim Comstock, who tested all the oils with a real world application to Commandos in mind.
https://www.accessnorton.com/Oil-Tests/NortonOil.php#9
Two brands that I had previously not heard of stand out, Royal Purple and Red Line. These are US produced oils.
I am considering changing to Royal Purple HPS 10w40 for the Monster.
Obviously the needs of a Commando are a bit different to an air cooled M900 engine, but it does get very good reviews elsewhere too.
I wondered has anyone heard of it or has tried it and what you reckon to it?