Today while riding home, I noticed a clacking noise coming from my primary. It has the same sound as when I put the transmission in first gear. It isn't continuous, it clacks at an odd rate that doesn't seem to have anything to do with the engine speed.

As I was going down hill near my house, I turned the engine off and coasted and it still clacked. But it wasn't continuous. After clacking a bit, it stopped and then started again. It sounds like the engaging dogs are randomly hitting each other.

Here's my question and maybe someone can help me out.

Is checking and rebuilding the transmission above the average wrencher's pay grade or something I can do with the service manual, patience and pictures?

 

Could be...Compensator nut has come loose OR (and do not rule this out) your wheel bearings are shot; as they can make a similar noise.

 

Thanks for the input. My wheel bearings are new, and I can feel the vibration in the engin when I hear the noise. It sounds like someone tapping on the primary case with a socket wrench, but not with a regular rhythmn.

It does sound like it could be the compensator nut based on what I have read other places. I'll check that and see what I come up with.

 

Pulled the primary cover tongiht hoping to find that the source of the clacking sound was obvious. Haven't had a chance to really look hard so maybe tomorrow night I'll get a closer look, but at first glance the sprocket nut seems tight.

However, when I drained the oil, there were a couple shavings stuck to the drain plug magnet. Not a lot, but a couple small shavings. The rest of the oil looked clear and there was no obvious shavings anywhere else.

Chaine tensioner seems worn so I'll replace that.

 

Following this with interest. Hope it works out cheaply for you.

 

Thanks Mr_Taipan.

It's one of those situations where I wish the problem were obvious even if it's a big deal. I'd rather have an obvious problem with a definite fix than stripping the entire bike down and not finding anything that stands out as the source of the problem.

It seems like there should be some obvious reasons for a clacking/knocking sound coming from the primary/transmission area and that I should be able to hunt those potential causes first.

I've read several forums/threads that give potential causes and have the following possibilities:

1) Loose compensator (though the Sportster doesn't have a compensator) or loose transmission sprocket bolt. At first feel late last night, the sprocket didn't seem to have any play to it but I'll check further tonight.
2) Excessively loose primary chain allowing the chain to slap the primary housing. This is a possibility but since I failed to check the tension before removing the primary cover, I won't know for sure. The chain tensioner pad seems pretty worn so I will replace that when I re-assemble. But at first glance, there doesn't seem to be any spot where the chain left impact marks on the housing. Also, the metal shavings on the drain plug were obviously ferrous and the housing itself isn't so any shavings from the housing would float free in the oil rather than stick to the magnet.
3) Starter failing to fully retract so the pinion gear hits the flywheel occasionally. I will have to inspect the pinion gear to see if it, or the flywheel gear show signs of violent contact and see if the armature retracts fully.

Does anyone have additional ideas what could be causing the clacking/clunking noise in the primary?
It doesn't keep pace with the engine speed, isn't internal to the engine itself as it won't rise and fall with revving the engine, and doesn't happen sitting still in neutral and revving the engine.
I can't be certain, but it seemed to only happen on the deceleration and slowing down but went away under load.
And lastly (oddly enough) it happened slightly when I shut the engine off and coasted down the hill. Just a light tap once I think, then nothing.

 

Sounds normal to me.

 

RIPSAW

I only wish it did, but there isn't anything "normal" about this sound.

 

My initial thought while reading your description of the problem was a loose chain hitting your cover (your #2 scenario). I would think a few shavings on the drain plug magnet would just be normal wear and tear and you may not see any marks on the primary cover if it just started hitting it.

 

This might be worth a read as it sounds similar to yours?

http://xlforum.net/vbportal/forums/s...=732942&page=4