In a word - No!

First problem is that to run it as the main lubricant requires a complete strip and flush as Castrol 'R' doesn't mix with conventional mineral or synthetic oils. It produces nasty build ups and will soon wreck your motor. Castrol recommend a solvent flushing oil must be run first. Remember Castrol 'R' is completely different from all other automotive lubricating oils in that it is neither mineral or synthetic, it is extracted from castor seeds (or beans) from the castor oil plant. This is where Castrol got it's name (castor-oil).

Second problem is that it's a straight or monograde oil in either SAE30 (R30) or SAE40 (R40) viscosities. Your lubrication, oil pressure and flow will be dramatically affected during cold starts amongst various other associated problems. It is also marketed as a "one use only" oil. In other words, you use it for one race meeting in a 4-stroke engine, then change it.

Third problem is that these days it is VERY expensive!

When you say you liked the smell when a bike passed you, the likelihood was that it was a 2-stroke running Castrol R I would guess? Assuming a 4-stroke motor is not worn and does not burn oil, or is working on a pre-war positive loss lubrication system, you won't smell it anyway.

An old trick, which I have used myself, was to add a capful of 'R' to as full tank of fuel in a 4-stroke engine to give the aroma. Back in the fifties and sixties a lot of folk did it under the misguided notion that it gave a little extra top-end lubrication. It didn't, but smelt good!

This trick won't work too well with a modern fuel injected engine with a catalyst and O2 sensor. Adding 'R' will clog up your injector, ruin your cat and stop your O2 sensor working over time. I've only ever done it on old carb-fed British bikes from the 50s/60s and only ever for the occasional hit!

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