[Steen Carstensen]

If you run Rotax series you have to run their oil, if not you can run whatever you have.
If your engine is sealed, I would not run castor as you can not get in there and clean the ring and piston, just buy some Motul or XPS and you are good to go.

[James McMahon]

It wont do any harm perse, other than perhaps gum up the ring and or powervalve sooner. Arguably it could affect your jetting too.. Probably the biggest debate would be on issues that might occur when you switch from castor to syth.

Just go with the Motul or XPS. You could sell the castor on ebay or EKN or something. Keep a bottle or two for the KPV if you still have it.

[Nick Weil]

Castor will do you no favors in a Rotax. It can really muck up the power-valve, and it will certainly throw jetting off. Both of which are critical for having a ‘fun’ time in a Rotax kart. Motul or XPS are your best choices.

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