Hi, i recently serviced my wee and discovered the installed IR plugs were cr 9 (the standard should be cr 8. They all looked quite nice and grayish, however, I proceeded and installed the standard cr8.
My question is what determines the plugs temp rating besides looking at their color?
For ex if the bike is used in hot countries, would it be wise to switch to a colder plug and vice versa?
My Rides: Suzuki TS50, Honda CB400 Superdream, Yamaha RD350LC, Triumph Tiger 650 (71), MotoGuzzi NTX 650, Ducati 750SS (93), Yamaha XTZ 750 SuperTenere, Vespa 200PX (01), Vespa Sprint 150 (68 ) ... Although ridden, never owned a four cylinder :-)