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Best fuel for pre 1986 two strokes?

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by Marx, Feb 19, 2016.

  1. Hi,

    Really simple, but just in case I'm really missing something obvious:

    What is the best/most optimum current fuel to run in a pre-1986 two stroke engine?
    Is there any real difference between unleaded, premium & what ever other octane fuel currently available if ran in an earlier model two stroke engine?
    Can two stroke engines use anything really?
  2. #2 pwbike, Feb 19, 2016
    Last edited: Feb 19, 2016
    Since a two stroke doesn't have valves and seats it shouldn't matter that there's no lead in the petrol.
    Just use an appopriate octane rating for the state of tune and a quality oil and you should be fine.
    Many older two strokes competition motors ran on methanol, so no lead there either.

    Thinking about it, I reckon the old Standard petrol was around 85-90 octane and Super was around 95-98
    so see what the owners manual said was correct for the old bike and use the same or higher rated unleaded. No lead will help with plug fouling too, you sometimes got whiskers of lead deposits that would either cause pre-ignition or short the plug gap.
    If in doubt, try 95 octane unleaded.
    • Agree Agree x 1