Here's a long one for you:

I recently purchased a 2010 Fat Bob with 6 miles on the odometer. After riding about 25 miles I started to notice a tapping coming from the primary at idle and when I started off in 1st. I figured it might still be breaking in, so I rode it to 200 miles with it not getting better or worse. It was disconcerning so I made an appointment with the HD dealership I bought it from to look at it.

At the end of the day, the dealership called me saying the bike was ready. I asked what they did to fix it. They said they could hear the issue and it is still making it. Ok... so you did nothing? They said they removed the other primary cover and everything looked fine. I asked if they saw any contact on the cover from the chain. They said no. I asked if they checked the compensator torque. They said yes. When I asked them to fix the problem they said to ride it until the 1,000 mile service and they'll see how many shavings are in the oil.

Passing metal around and the wait-and-see method wasn't ok with me. When I got the bike home I removed the primary cover. It had oil on the outside and bottom of the inner primary case, so they definitely took it apart. The first thing I noticed was chain contact marks on the bolt boss underneath the compensator on the outer cover. So they obviously lied to me there, which made me livid. I next checked the chain tension. I didn't measure it exactly but it was roughly 5/8-3/4 of play without compressing the automatic tensioner, and easily over an inch with tensioner compression.

I then dremeled the cover smooth and rounded where it was contacting, hoping that would possibly fix my problem. After putting it back together and adding new HD Formula + oil, it still made the noise, just not as bad. I'm guessing it still hits but the rounded corner is less of a harsh noise.

I have also changed the oil to Amsoil 20w-50 and it made it marginally quieter. It is more or less absent when the bike is fully hot (I'm guessing from a tighter chain), but noisy when cold and all the way up to fully hot. It's not a rod knock or lifter tap, and I'm almost positive it's not the compensator. It's not a constant tap, but a: tap tap tap... tap tap tap tap... tap tap tap.

I have tried the 1st gear to 30mph and stomp on the rear brake, but to no avail. I am now thinking of ratcheting up the adjuster tighter one notch. I currenly have zero whine from the chain and figure it can't hurt to try. I'm going to try accessing through the derby cover (I read somewhere someone was able to achieve this). If it whines afterwards, I'll reset the tensioner.

What are your thoughts? I've spend countless hours of reading trying to pinpoint what's going on and possible fixes. I've read a lot of threads that were close, but not my exact problem. I would really appreciate any input! Thanks in advance.

 

Not sure how you're going to "notch up" the tension on the chain tensioner. As I understand it, these are automatic chain tensioners controlled by spring tension. If you figure something out, please let me know. It would be good knowledge to have just in case I need to use it. Thanks!

 

I have read that if you give the wedge a push when cold you can tighten it, if the spring is weak.

 

Updated HD tensioner 39929-06A Double check me but I have heard that is a heavier duty part. I have seen it and it looks way more beefy. I dont personally know if there is supposed to be any slack on the top side of the chain. But you should definitely not be having any contact inside the cases,via the chain.

 

I believe the chain drive primary is designed to clear the inner primary cover ... it should not make contact with the inner face of the primary cover at all ....

Did you check to see if there's a link on the chain that has come loose on one side or something ...? If there was a half a chain link loose, it could cause the chain to come apart or break while you're riding ....

That just sounds really strange that the chain is wearing on the inner face of the primary cover ... I think you should take it back to the dealer and if need be, remove the cover yourself and show where the chain is wearing ... it should be covered by warranty .... This is not something you should be left to figure out on your own ... it's a brand new bike ...!

Good luck and let us know how it turns out ... and what was causing it ....

R/
'Chop

 

Yes it is. The bottom rail is about twice the thickness of the original part.

 

Everything I can find says there should be similar tension as the manual style. I've heard of these tightening too much and causing whirring in the primary, with the possibility of damage. Hence, I don't want to go too tight.

 

I did look very carefully at everything, including the chain when I had it apart. The chain did not appear to have a loose or deformed link and the only contact was on the outer cover.

I do think that this is a known problem by HD, as the contact point is the only area on the whole cover that was seriously ground down from the factory. I'm leaning towards this being a lazy tensioner after lots and lots of thinking.

I'm very hesitant to take it back to the dealership, as I attempted another appointment and they were annoyed/pissed that I wanted them to look at it again, so I said forget it. Maybe I'll take it to another, but something this "simple" I'd rather do myself, as I trust myself more than anyone.

 

Man it just seems like the chain is too loose. But the only puzzling thing to me is didnt you manually tighten the tensioner?? If the spring was weak than that should in theory take enough slack out of it.

Here is my thoughts on this.

The chain will heat up with use and soak up engine heat as well, actually lengthening the chain at its highest temperature. So the only way it will tighten the chain correctly is under its own spring tension while hot. Therefore not being able to manually tighten chain when open and cold.
I would think the updated tensioner,and a nice and hefty downshift while warmed up should take out the slack you are having issues with.
I wouldnt have any issues clearancing the case further as well, but must say that I would be completely pissed being a new bike and all.
I have an 06 Street Bob and have to buy a new stator and rotor because they have a known issue and refuse to recall it!!
Welcome to Harley Davidson.
I love my bike, but I am learning quickly how to work on it.

 

I have not manually advanced the wedge on the ramp. To this point I have left it alone to do its job. I have done A LOT of hard accels and decels to try and stress the tensioner into moving, but it seems to not want to budge.

Although I agree that a chain will expand with heat, supposedly the cases, compensator, and clutch expand more, making the chain tension tighter when hot. If you look up specs, it calls for a tighter spec on the manual tensioners and looser when cold.

I have found threads with the same symptoms as mine, even one with the same contact area. Both threads say that the tensioner is to blame but didn't say if they advanced it manually or just replaced it. I figure if manually advancing it fixes it, it will hopefully work in the future or there will be few times I'll have to do it after the chain is done stretching.