Have been in AZ for the winter putting miles on my 09 Ultra Classic (about 12,000 miles now on the bike). I noticed last week that at speed (65 MPH in top gear) under slight acceleration, the I can hear slight "pinging" like pebbles hitting the front fender. Frankly it sounds like detonation to me and perhaps only a timing issue. I thought it was bad gas but after a couple of tanks at different gas stations, it remains the same. It has been in the mid 80's here lately and it seems worse with the warmer temps....no stutter or slugishness, just pinging. The engine is stock except for a set of Crusher mufflers but the mufflers have been on for some time. I have about 3 weeks left on the warranty so I will take it to the dealer before expiry but was wondering if anyone out there has experienced the same symptoms. Thanx in advance.