I agree ... happened to me on my '03 Ultra

 

Am I the only one who thinks that recording is of a single cylinder motor?

You checked compression on both cylinders yet?

 

Interweb sound bite diagnostics are poor at best.
I am usually unable to do it correctly.
After witnessing that most HD engine issues stem from the cam chest area, begin there.
If the comp nut has created damage, from lack of proper pinch on that assembly, we reduce the OAL by .060" to insure positive clamping ability.
Scott

 

Hard to tell from audio but I would guess a lifter roller failure.

 

Finally made time to work on this

@Ed Ramberger I checked the chain tension before removing the assembly. It was within specs at 5/8"
@98hotrodfatboy: Any thoughts on what might be going on in the cam chest?
@Skinman13 so you're thinking cam chain tensioners maybe?
@Bowhunter61 Good point that since the assembly spins both in gear and in neutral shouldn't make a difference
@djl the nut was tight and I was not able to move the Sprocket Cover by hand. It seemed tightly clamped.
@Cromagnon: sounds like a 2nd vote for cam chain tensioners. I'll be posting findings once I have them
@mattbastard: The motor is firing on both cylinders and there is no change in the smoothness of the engine when the noise starts. I will be doing a compression check anyway tho
@Hillsidecycle: Thanks for the tip: The assembly seemed very secure
@BVBOB: Will be finding out soon enough if you're hunch is right.

I decided it was time for a new clutch anyway, so that drove my decision to start with the compensating sprocket assembly.

I pulled the clutch basket and comp sprocket. The nut was not at all loose, and I could see no signs of anything out of the ordinary. I wish I could find guidance for inspecting the compensator assembly, particularly the spring, but I couldn't find anything online nor in the FSM, but visually it looks great. Some minor wear on the lobes, but the sprocket teeth all look good.

Video of the Sprocket Cover Video of other assembly components Video of clutch basket
Puled to rotor and it looks fine too.

I guess it's on to the cam chest. Any thoughts on common failure points in there that I should be looking for?

I *really* appreciate your help on this!

 

Cam chest open, rocker boxers off, lifters out.

First look at components doesn't show anything obvious: inner and outer hydraulic chair tensioner shoes don't look wasted, Torrington inner cam bearings look good, lifters aren't falling apart, push rods and rocker seem good at first glance. Tomorrow I'll do a detailed inspection of these parts and see how they look. Was really hoping something would stand out as an "ah hah!", but not yet. Stay tuned

 

Having not found a smoking gun that would explain the racket from my bike, I finally pulled the stripped engine and took it to R.E. Engineering in San Jose CA to have them open the crankcase and look for a cause within. Still no smoking gun. Apparently there's a pressed-on journal on the crank that was spinning freely which required attention, and a rod with a pit in the bearing journal that was large enough to cause concern about future problems, but we never found anything that we could point to and say "THIS is what was causing the noise." The only thing left un-touched was the transmission, and it seems very unlikely that this noise was coming from there.

Anyway, I got the motor reinstalled and ran it for the first time yesterday.

My heart sank when, during the second heat soak, I heard the noise again.

I had recorded video of the heat soak process as a just in case measure against something going wrong, so I could show the builder the video to prove I had followed his directions to the T for the process. I grabbed my video, rented a U-Haul motorcycle trailer, and took my bike to the builder so he could fire it up, hear the noise, and I'd leave my bike with him to make whatever correction was needed.

H fires up the bike, and a minute later there's the noise. He turns to me and says "Man, I'm sorry. I should have told you those Easy Start cams make noise at low RPMs". lol... damn, that was the best news I've had in a long time. Trailered the bike back home and took it for a careful putt around the block, and today it goes in for a break-in dyno tune.

Will post more results as they emerge.

 

Alright, the verdict is in.
Rode 27 miles nice and careful to the shop for a break-in and tune on the dyno, and an equal number of miles home. The noise is definitely gone, and this motor is nice and strong. Still don't know what caused the problem originally, but I know it's history.

104 HP and 117 TQ

 

Nice.. I'm sure it moves out very well... Ride safe man...