I went back through my past bike maintenance schedules, and in most cases the recommendations from the owners manuals were to replace the plugs between 8K and 12K miles, and many have valve inspections or adjustments that often. The nice thing about the PA is the valve checks aren’t necessary.Took delivery of my Pan Am last June. Now have 11k miles on it. Wonderful bike, very pleased with it's performance, handling, comfort. However, I have learned that the maintenance schedule specifies replacing the four spark plugs every 10k miles! This is in addition to a fairly expensive service of torquing fasteners and checking wiring connections that is supposed to be done every 10k. I've owned and ridden motorcycles for over 50 years, including at least one of every widely sold brand. I've never had to change plugs that often on a four stroke engine. With the electronic ignition and fuel injection now common, it's hard to imagine this is really necessary. Has anyone seen their plugs after 10k, or have any experience with this?
For plug replacement My GS1250 was 12K, Yamaha Venture was 8K, HD Heritage Softail was 10K, Yamaha VMax was 12K miles, Ducati Scrambler was 15K miles, Suzuki B-King was 7.5K miles. I’ve had 30+ bikes over the years and I recall all having similar recommendations. My experience is the higher HP, higher compression engines tend to burn through plugs faster, and this is a 13.1:1 compression engine. Now, whether people choose to change the plugs per the recommended schedule is another thing. I always have because it’s the heart of the engine performance and affects both the power and mileage.