I have an 06 fat boy,50,000km started up after a winter of changing all fluid’s except trans and adjusted all cables. Noticed a slight noise like something tapping on the exhaust pipe, went for a short ride but it didn’t get any worse. Next day took it to work and noticed it getting worse, on the way home got scary worse and turned into a rattle which got worse with RPMs. I thought it might be a cam chain tensioner but they aren’t that bad. Where would I look next, I’m thinking pulling the rocker boxes off and start there unless anyone might of had a similar issue to point me in the right direction. Thanks!

 

Start with the exhaust system and make sure everything is tight and none of the brackets or heat shields are loose.

If all is good there, try and isolate where the noise is coming from, right side, left side, upper part of the engine, lower part, front, rear, ect.

 

Definitely look for something making contact with the exhaust. Do it with the bike running to and get down on the ground to look for it. I did a big bore job for a guy and about 2 seasons later he calls me and says he suddenly has an engine noise. I go over start it up and hear nothing...hmmm...he swears its making a racket while riding. I was down on all fours, with it running and i put my hand on the floor board to stand up and presto...noise...not engine noise though. He didn't tell me tipped it over a few nights ago and it pushed the floorboard just enough so when the rubber pad got pressure on it, it would rub against the heat shield. Otherwise I'd be suspicious of the lifters at that mileage. How do you know the cam shoes look good? Id replace them just because