Let me start by saying I'm not a gear head AT ALL. I've got an 08 fxdf with a 120r that started making some funky noise lately. The motor has less than 5,000 miles on it and since it's under warranty I took it to the dealer that installed the motor. As soon as I pulled up in front of the service dept. the tech that always works on my bike came out and said that he heard the sound when I pulled in. He said it sounded like a lifter and that a lifter probably wasn't "pumping up". I asked if this was common on the 120 motors and he said it wasn't. Needless to say I had to leave my beloved Bob at the dealer. Hopefully they can get it in right away and I'll get it back while the weather is still decent.

What the hell does a lifter not "pumping up" mean? Is this something major? Was there something I did to cause it?

Sorry for asking such basic questions but like I said I'm not a gear head and I could use some help.

thanks in advance for any help or advice any you technically savy folks can give.

 

The H-D OEM hydraulic lifter has .200" of "travel"; the range of vertical movement of the pushrod in the lifter body. The OEM non adjustable pushrods are designed to sit at the mid point of the travel, .100", leaving another .100" of travel. As the motor heats up, everything starts expanding and the valve train stack up dimension changes as the cylinders get longer. The lifter chamber is fed with oil from the engine oiling system and is under pressure, so when the cylinders elongate and introduce lash into the valve train, the lifter, "pumps up" to maintain zero lash, i.e., zero clearance between the rocker arm and the valves.

When a lifter fails to pump up, lash or clearance is introduced into the valve train and presents as noise; lash between the pushrod and rocker arm and/or lash between the rocker arm and valves.

Unfortunately,the OEM lifter quality has suffered lately due to the manufacture of the lifters now being in Mexico. The tried and true -B lifter has been replaced by the -C lifter and the quality is hit/miss. There are good aftemarket alternatives like VThunder, HQ Black Ops and Woods Directional but to maintain warranty you are probably stuck with a -C lifter replacement. Ask your tech if he can find you some of the "old" -B lifters.

 

Thank you. You explained that in a way that was understandable and didn't make me feel more ignorant than I already do.
I appreciate it.

 

One thing I left out that does not come up much in discussion about valve train noise is the fitment of the lifter in the bore. If the fitment is too loose, the lifter will have a hard time staying "pumped up" and tend to bleed down. The MoCo doesn't check fitment very close and so if you get a motor where the tolerances are min-max, like the lifter bore is the max and the lifter is the min and/or the pushrod is the min and the cylinder is the max, etc. you get one noisy motor. On the other hand, reverse those tolerances and you get a quiet motor.

 

Is that something that a person could complain about and get covered under warranty? The motor on this bike is still covered by a 2yr HD warranty and I'd like to get everything taken care of that I can. Thanks again for your help.

 

You're kidding, right? They will laugh you out of the shop; don't go there. The only way to check is with a dial bore gauge to measure the lifter bore and micrometer measurement of the lifter to see what the clearance is. If you continue to have valve train noise, you might go there later but probably better to go with the obvious now. One thing I have learned from another forum is that the -B lifter OD is pretty consistent and the fitment issue presents in the variance in lifter bore diameter. You must also realize that high lift cams like the 266E (.658") put more load on the liftes which have a thrust side. If you can't get rid of the valve train noise, you might consider installing lower lift cams.

Let the dealer replace the noisy lifter and your problem might go away. If not, see if the dealer will allow the replacement of the OEM lifters with an aftemarket part and still honor whatever warranty you have left. If the dealer will allow that, there are several aftermarket lifters that might work better.

 

well, it wasn't a lifter after all. I found a pic on line because I didn't think to take one at the time.

The circled area is the bolt that sheared off. The noise was the head of the bolt bouncing around and banging against the cover. The tech was speechless. He said he'd never seen anything like it before.

The plan now is to try to get what is left of the bolt out. If they can't get it out then they'll start tearing it down.

Any ideas on how something like this happened?

 

Glad you found the problem. You need to buy a lottery ticket! You are so lucky that the head of that bolt didn't find its way between the cam chain and a drive sprocket; you dodged a major load of bad juju.

No idea on how that happens unless the bolt was just defective.

Shouldn't be hard to get out; IIRC, that bolt is only torqued to 25 ft. lb. Worst case, new cams but I don't see a problem getting the rest of the bolt out.

 

They did manage to get it out. I should have it back today. Once again thank you for your words of wisdom.

 

Well said dj!!
Scott