Originally Posted by Twin-shocker
Using full synthetic pre mix only oil, for air cooled trials 70:1, for water-cooled trials 100:1, for recreational off roading 60:1, for serious MX racing 40:1 will work fine. If you choose to use dual purpose injector type oils, increase amount of oil by 20%, as these oils are generally thinned by the addition of kerosene, so are a lot less oily than proper competition lubricants.
The different types of 2-T oils was confusing. Some might be premix-and/or-injection and some are premix-only, like the Bel-Ray MC-1. Thanks for the excellent information and clarification, Twin-shocker. Based on your information I will use the PREMIX only type and not the "dual-purpose" type.