I have a new HD4 which is making a popping sound (not a creak) especially when putting the power down (more so when standing and mashing). Occasionally, I hear and feel the pop over undulations in the trail. I have checked torque (specs) all linkage bolts, clevis to swingarm, upper and lower shock mount bolts. I did replace the original shock bushings with ones with tighter tolerances as there was some play in the upper bushings. I am running a Fox X2. I also checked the torque on the bottom bracket and that was good. I wonder if there is some stiction with the new bushings, enough the cause the popping? I haven't checked the headset, but I don't think it is coming from there, but I know sounds can come from many different areas. It's driving me nuts and certainly doesn't give me a warm fuzzy when I am pushing hard. Any ideas or advice would be appreciated. Thanks in advance.