The Cabri G2 can be run on "alternate fuel" as mentioned in the RFM, although I seem to recall an engineer told me "temporarily" means there is limit on the number of flight hours the alternate fuel grades can be used between 50H checks.
"Alternate grades
Automotive unleaded gasoline can be used temporarily if it complies with EN228 or ASTM D4814 and following conditions :
Minimum octane rating ............................................................ . 98 (*) Alcohols (ethanol, methanol, etc.) ............................... Zero content
(*) (RON ≥ 98 and MON ≥ 87) or AKI ≥ 93
Note 1 : When using alternate grades, power is limited to maximum continuous power. Refer to page 2-8.
Note 2: Refer to page 4-15 for management of possible fuel gage error."