The big twin comp is for 07 and up. It would seem the 08 comp is the same as the 07.
Ron

 

I recently posted on the harmonic balancer you mentioned, and while it will do more or less take harmonics out it will do very little to stop vibration. It's not designed to do that. Actually with such a short crank it may have no use at all. Google it and read some of the user reports. I was curious about it once as well.
I also doubt very much , even the crappy 07 comp will cause the vibration you mentioned. To get that kind of shake in a B motor, someone forgot to put the chain on the balancers, or sprocket timing has slipped on the crank throwing throwing the weights out of phase or you have considerable crank runout. In my case with the stock comp and the big twin comp the actual buzz is the same with either due to my crappy crank. Where the new comp shines is taming the pulses. Buzz is an up and down motion and the pulses are back and forth sorta.
Ron

 

Ron, I agree with you on the issue of the starter bang. I am not a "motorcycle mechanic" but I was a machinists mate in the navy working on hydraulic systems aboard nuclear subs. I have been in the industrial maintenance field for 29 years and am presently employed as a reliablility engineer, which means I identify bad situations and make suggestions for improvments before equipment fails. I work with mechanical and electrical controls, and am considered by my peers to be a "go-to" guy for hard to diagnose equipment problems. None of this is meant to be a brag, just qualification for remarks I am about to make.

I recognize the twin cam starter noise as a condition which has a high probability for causing failure. They just haven't been out long enough for the problem to manifest itself. I also feel that the compensator is probably causing the noise in my engine. Even if it isn't, I am still going to replace it with the upgraded SE part.

After dealing with two H-D service shops I have to say that I am not impressed with their level of technical understanding. I believe that many are trained to follow a laid out set of steps for diagnosing certain problems (like the ones in the service manual) but few have the intuition and natural ability that makes for a truly remarkable technician that can figure out problems based on symptoms that are not on their list.
I also think that they are doing their best, based on their ability and understanding.

I have until sept for my warranty to run out. I guess I'd better check on a warranty extension.
Tom

 

You are correct. All will give trouble eventually. There are two failure modes to the unit. First is a weakening spring pack which make the unit loose and rattle, generally accompanied with a reduction in starter knock. Along with this comp effect is lost with more pulsing in the drive line, which some people mistake for vibration. However the stacked components may still be tight from the original bolt torque.
Second form of failure and most common is over time the constant pounding from spring pack compression into the rotor face will cause the metal to compress on the back side of the rotor at the spacer. This loosens the compression of the parts from it's original torque on the bolt. Due to loctite and lack of knowledge the tech will assume it is still tight, but in reality it's not. The rotor will start to impact the splines from engine pulses as well as the extension shaft. A low grade knock like rod knock will appear when leaving a stop light in first. This is a loose rotor. There will be also signs of the extension shaft end that's against the rotor showing signs of fretting at point of contact. You will see many of these indications when you pull it off and inspect it, plus comparing the new and old models the first thing you will say is wtf were they thinking when they designed the stock unit. Not one single part is the same in the new model, as in it's progressive cam loading in ramp design with cam reversed to not use the high wear area of the tips, plus the 3 stage spring pack. While still not perfect in some areas, it should be much more successful in the long run.
Ron

 

Good information all around. My 05 Heritage with 18K miles started displaying a minor vibration mostly felt at the floorboards or more so just resting a toe on the engine guard. Your giving me good places to check. Thanks