Primary chain keeps getting loose

[JW113]

A few weeks ago I was hearing a clacking noise coming from the left side of the bike, seemed to be from the primary. I popped the inspection plug, sure enough, the chain was loose and must be hitting the housing. I adjusted it to 3/4" slack, and all was well. Until a couple days ago. Again the same clacking noise. Pulled the plug again, and yet again the chain is loose as a goose. WTF? Either the chain has decided to start stretching like crazy with all this new found horsepower (LOL!), or the shoe is wearing badly. The adjustment screw and lock nut are tight, so it's not like that came loose. I really didn't want to pull the primary cover off today, but guess I need to have a look and see what is going on in there.

Anybody ever heard of this before?

-JW

[Ohio HD]

Is that the original chain? Could be it's just shot. On rear chain drive bikes, when the chain (non o-ring) starts stretching like that, they beak soon.

[JW113]

Yes, far as I know it's the original chain. And yes, going to need to change it soon. But I did find out what happened. I think.

In preparation to pull the primary cover, I dropped the oil out. WHAT THERE WAS OF IT!!! An ounce, maybe two, that's all that came out. So it had been running for some time with essentially no oil in the primary and trans. I could not wait to see what was behind the cover. As it turns out, not much to see. Amazingly, everything looked 'normal'. The ATF that was in there had turned a very dark brown color. Even the nylon adjuster shoe was not worn at all. Since the chain was slack, the only thing I can think is the chain must be very worn. But even that did not feel real loose. I can't imagine what the trans must look like, but it was shifting fine when I rode it last, and not making any noise. Hmm.

So why no oil? The bike does not leak a drop. No oil on the floor, nor all over the rear section. The ONLY think I can think of is that the drunken pendejo that worked on it last did not fill it back up with oil. DOH!!!


At this point, am just going to button it up, fill it up, and start rounding up parts to replace the chain, and rebuild the transmission.

-JW

[Burnout]

The output bearing rollers in the trans runs right against the mainshaft.
If that bearing goes dry it will eat the mainshaft.
That bearing gets lubed/cooled by oil thrown up by the gears to a trough in the roof of the trans that feeds the bearing through a 1/8" hole in the case.
If the seal leaks oil it literally gets pumped out rapidly.

Check your manual, A XL has a tighter chain spec than a big twin.
Also verify the chain is running straight, there are different length clutch spacers to get the chain straight.