Vortex ROK Senior oil mix and fuel

What is the recommended fuel and oil mix for the Vortex Rok Senior engine, and what octane petrol should be used?
And does the engine need to run castor oil, or is it OK to run fully-synthetic two-stroke oil?

Thanks in advance😃

According to the ROK Cup Rules:

It says ROK GP runs 4% oil to fuel. That is equal to a 25:1 ratio or 5.12 oz of Oil per Gallon of Fuel. Also states to use a “High Quality Synthetic OIl” and a minimum Gasoline Octane rating of 95. Unleaded, Leaded or Race Fuel is okay. If you end up using Pump Gas, Make sure it is Ethanol Free and meets the minimum octane rating. Ethanol will play havoc on the jetting and eat up the seals in the carb. Underrated Octane fuel will detonate too soon and cause ignition timing issues, hot running conditions and possible engine failure from what I understand. Race fuel is best for consistency of quality and octane, but comes with a higher price tag.

@alvinnunley could probably weigh in more on the effects of fuel octane and timing.

If you plan on racing, always check the rules of your event as many club, regional and national events may have a spec fuel to run.

Hmm. It doesn’t specify the octane method they are referencing with 95. That’s a shame.

Unless you’re looking for last few hundreths, keep the timing at 3mm BTDC as recommended.