JASO FC oils are defined for low smoke performance and deliver superior performance to JASO FB in terms of exhaust smoke and exhaust system blocking. They are designed for use in two-stroke motorcycles and small engine equipment.

The main physical, chemical and engine test requirements, according to the current version of the standard (JASO M345:2004), for JASO FC oils are shown below:

Physical and Chemical

Requirement Methods Unit Limit
Kinematic Viscosity (100°C) D445/K 2283 mm2/s 6.5 min.
Flash Point D92 or D93/K 2265 °C 70 min.
Density (15°C) D1298/K 2249 g/cm3 Report
Pour Point D97/K 2269 °C Report
Colour (visual inspection) D1500   Report
Sulphated Ash D874/K 2272 % mass 0.25 max.
Phosphorus D4951/JPI-5S-38-92 % mass Report
Nitrogen D4629/K 2609-1990 % mass Report
Sulphur D2662/K 2541-1992 % mass Report

Engine Testing (JASO FC)

Evaluation Item Test Method JASO FC

Standard Index

Honda Lubricity (LIX) JASO M 340 95 min.
Initial Torque (TIX) JASO M 340 98 min.
Honda Detergency (1 hour) DIX JASO M 341 95 min.
Suzuki Smoke (SIX) JASO M 342 85 min.
Suzuki Blocking (BIX) JASO M 343 90 min.

The significance of the index numbers:

The numbers for each evaluated item, i.e., Lubricity, Initial Torque, Detergency, Smoke and Blocking are all index numbers which are associated with performance in each category.  Basically, the higher the number, the better the performance in that category.

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