Don't get confused with R30 being the same as A747. They're different, and their applications are different.

R30 is a castor oil, and is pretty good at everything. We used in transmissions on NSR250 and RS125/250 as it's lubricity is excellent, but it's a tad thick and gooey. Not to be used in wet clutch applications though as it'll slip like a...errr...slippery thing!

As a two stroke oil, R30 also has it's uses. It mixes with alcohol without breaking down so that's one useful thing to note. It also retains a very high film strength at high rpm, which is a necessity for small capacity/high revving strokers such as fixed gear go-karts.

In lower revving engines (~14,000rpm) it's not so good. It smokes and can gum up the rings, foul plugs etc. You also need a lot of it in the premix. 15~20:1 mixes are not unusual and this can affect throttle response.

R30 doesn't like to mix with other oils, which is ok if you're only ever gonna use R30, but don't think that you can change brands/types without completely draining and flushing.

A747 is a castor based two stroke racing oil. It's application is for racing two strokes. simple as that.

The usual mix is 30:1, but we've used very lean ratios in experiments with Castrol with no real bad affects other than a temperature rise (and associated power loss).

A747 also has the magic of replacing the octane of the fuel that it displaces (allegedly), so if you have a 100 octane fuel and add A747 at 3% (or whatever) you won't get a drop in octane. R30 doesn't do this. The octane level will drop.

A747 is for premix only. It will not flow through an injector so don't go this route.

A747 was developed for leaded fuel, and although I've used it without issue in uleaded a new generation of A747 is available now (XR77), specially blended for ULG.

It's not a good choice for the road, unless you ride like a nutter at all times, as it'll smoke and foul plugs at low rpm. It's a race oil, so works within it's design window, which is high rpm, high pressure, high temperature environments.

Oh, there's one thing that both oils do have in common, other than the castor base, and that's the smell. It's delicious!

You can actually buy little 50cc packs of R30 here in the bike shops to throw in the fuel tank just for the smell. It's great!