2008 suzuki GSX 1000 motorcycle indicates on

FI = Fuel Injection. The FI computer is telling you that it has detected a problem and the code for that problem is "C13". Telephone your dealer and ask what that code C13 indicates is wrong. Then you can determine if you want to try the fix, i.e. "clean the air filter", or if the shop must do it, i.e. "# 3 injector is restricted".

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F1 is actually indicating FI - fuel injection system problem. To find out exactly what that problem is you will have to hook the bike up to the computer diagnostic tools to find out.