I installed a HB125 primary chain tensioner for my 2001 road king about a month ago.
I literally am in the middle of changing my primary oil, and it came out grey with decent size metal flakes. I if I shine a flash light through the oil, I can see the metal, so I know its not water or anything else. I use the amsoil synthetic that can be used in all holes, and my primary fluid has always come out clean, until this point.

Pre-installation I noticed when I was playing with the hb125 in my hand, dry, I would have to fiddle with it, for it to actually compress, meaning it wasn't smooth compressing it up and down until I could push it past a certain starting spot by wiggling it around. Is that normal, because even when installing it, I thought if the tension comes out of this thing, its going to get stuck and no longer compress if it loosens up to a certain point. I installed it in the correct direction with the little nut facing the front wheel and the plastic block was in correctly also, and my chain tolerance was in spec when I put it back together originally, which I'm going to go check again after writing this, so I'm kind of at a loss here as this is the only thing I replaced was this tensioner at that time, because I was sick of doing the manual adjustments. I just want to emphasis again with no pressure on it, It didn't compress smoothly, almost like something was blocking it, and I would have to wiggle it around in my hand using lots of pressure to get it to push by something that was obstructing it. If you guys tell me this is normal, I guess I'll have to start looking for other stuff.

This was pretty bad though, because I ended up using zip ties to keep it compressed so I could squeeze it under the primary chain, because I couldn't keep equal pressure across it with one hand while trying to install it, and it would pop loose and I would have to take it out and mess around with it to get it to recompress to the point it would fit under the loose chain..

I did have some initial whine when first using it for about ten minutes. Not sure if it was getting itself lubricated fully or not but it went away with in the first ten minutes or so of riding ( I did the bench prime with oil pre-install) , I just can't see that causing the oil to be as dirty as it was. Its not sludge or anything, but its pretty bad for about 1500-2000 miles considering I ussaully go 5000 miles between primary oil changes and the oil comes out clean with very little metal on the drain plug..

I know there is that other m6 one or what ever its called, but I would rather here about this one seeing I choose this one after lots of research on this site because it appeared to be well reviewed for the most part.

 

If it were my bike I would reinstall the stock unit.