The L82C is cooler, like the NGK B7HS, and the L86C is hotter, like the NGK B6HS. It depends on the climate you ride in. Warmer climate with thin air, go with the hotter plug, colder climate with dense air go with the cooler plug. Also, if you ride stop and go, go with the L86C but if you ride long distance and at high RPM's go with the L82C. The stock plug is the L86C, but there are always variations to the rule.