Loud clunk when starting

[szunker]

Hi,

I just purchased a 2009 fxdc great bike sofar, However when I start the motor I hear a loud metalic clunk/clank then it starts. My dealer says that is is the compensating sprocket and it is normal. I guess that I believe him but just for a piece of mind does anybody else hear this also?

[dyna08]

Don't worry about, he is probably right.
I heard the same thing with my 08 FXD.
Went away after the first 1K miles.

dyna08

[DAKSY]

My 08 Cross Bones does it...
The Service Manager at BHD says it's normal, too...
Wonder why my Sporty never did it?
Drove me nuts at first, but if it still does it, I don't even notice...

[Ed Y]

Here's info straight from HD.

TT258 – August 9, 2006
Primary Drive / Starter Noise Complaints

Several dealers and customers have commented about a “clunking” noise coming from the primary housing during start up. Most dealers suspect a loose compensator because the
noise seems to come from the front of the housing. Customers tend to associate it with a starter issue like improper starter drive engagement into the clutch’s ring gear. In fact the condition they are noticing is what is referred to as “Starter Knock”. This is a normal sound and condition for all 2007 and later Twin Cam models.

Changes in the primary drive system increased the diameter and inertial effects of the rotating components (clutch and sprocket assembly, ring gear, and engine sprocket). Also,
the engine control system is calibrated to start the engine asquickly as possible (short crank to run times) and to run up to the predetermined engine idle speed as quickly as possible to provide very positive starting.

Because the engine fires and then runs up to speed very quickly, there is a large torque input and instantaneous speed differential between the engine and spring loaded compensator
mounted between the engine and the driveline. Thecompensator is there to dampen the high torque spikes inherent in a large displacement V-Twin.

Because of the increased inertia in the rotating components in the driveline, their rotational speed cannot increase as fast as the engine, so the springs in the compensator momentarily
bottom and results in the sound that you hear.

The same sound exists in the 2006 Dyna models, but to a lesser extent. The increase in displacement to 1584cc increased the torque spike and speed differential in the 2007’s and causes the sound to be more noticeable.

There is no damage associated with the compensator bottoming.

Identifying characteristics of this condition:
1. It may be intermittent, as it is dependant on the start up conditions and how quickly the ignition and engine RPM occurs.
2. It will be a single event. Once the starter is disengaged or the compensator is loaded the sound will stop, unlike a loose sprocket assembly.
3. The condition may be more noticeable on Touring models due to the shorter primary drive (shaft center to center distance) and associated shorter chain run. The extra
body parts like fairings and saddlebags also tend to reflect powertrain sounds upward, towards your ears.

[jhawkr]

My 2008 FXDC does the same thing. At 2800 miles now it doesn't do it all the time but it still happens occasionally. It really bugged me at 1st but it doesn't worry me now that I know they (late models) all do it.

[fatboydon24]

my o5 fatty does it.i think its cool when it does it.fires right up instead of turning over and over.

[szunker]

Well at least the dealer is not pulling my chain, It is variable some times louder than other starts, My old 06 sporty did not do it, but now I feel better that it is not isolated to just my bike.

[stanley4512]

My '04 RK has done it only twice. Very annoying.

[szunker]

Ed Y you know your stuff! I see the there is a screaming eagle compensator in the 09 catalog which states that it has a stiffer spring,will this cure the clunk? and is there any other fix for the noise?

[KBFXDLI]

My 2006 TC88 does not do it. The longer stroke of the 96 engine makes it more pronounced. But I understand they have a new SE compensator that is better. The moco claims it doesn't harm anything but I have a difficult time believing that if it keeps doing that for 50-60-70-80-90,000 miles and all the starts and bottoming out of the comp. It has to effect the shaft runout sooner or later. SOme guys have shimmed theirs with spring steel and it eliminates the bang.

[dickey]

My '06 FXD35 did it, and my '08 FXDC did it. Perfectly normal. My '04 Fatboy doesn't do it, but probably 'cause it's carbed.