I have a problem with my 1996 883 Sportster with approx 10K miles: When downshifting to 2nd or 1st gear, there is a loud clatter that starts. (The clatter is a new noise and not the normal noises) It will even start clattering when at a complete stop and downshifted. Once the clatter starts it will continue if shifted into neutral. The clutch doesn't make a difference engaged or dis-engaged. The clatter stops when the bike is accelerating and up shifted.
I've adjusted the primary (several times) using the FSM as well as the old school "tighten it until it starts to whine, then back off slightly technique". I've also tried running it a little on the loose side and a bit tight. There is no change in the clatter. The noise is loudest in the area of the starter motor.
I removed the primary cover and inspected for unusual wear. There was a very small amount of metal particles on the magnetic drain plug. The tensioner shoe was worn so I replaced it. The flywheel and starter gear looked to have normal wear, but I pulled the starter and had it tested anyway. It tested good.
A Harley mechanic looked at the bike and replaced the detent and clip. He inspected the clutch pack, gears and shift fork and said they all looked good. He could find nothing wrong. After buttoning everything back up, readjusting the belt, adjusting the clutch, filling with 85-140 mobile-1 gear lube and taking for a test drive it still makes the noise.
I'm hoping that I missed something simple. I'm baffled and the Harley mechanic is stumped.

 

Well for starters, 85-140 gear oil is too high of a viscosity for a Sportster. It's fine in a big twin where it's used for the tranny only (they have 3 oil holes), but a Sporty (with a combined primary/tranny box) should be using nothing heavier than a 75-90 Gear Oil.

If your mechanic told you to run the 85-140, find another mechanic.

 

cHarley, good catch. I double checked and it is in fact running 75-90