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[Hoist!]

Before you freak out, this is not my bike! It's a friend's who's just out of W.....ty on an '07 96". Crank failure caused it? Compensator failure only? Crank Position Sensor failure causing the whole setup to run out of whack? I've never seen a failure like this! Anyone ever see this before? WTF?!!! dj, you're on! Thanks!

Hoist!

[skreminegul07]

China and Wall Street

[Sean M Cary]

Before you freak out, this is not my bike! It's a friend's who's just out of W.....ty on an '07 96". Crank failure caused it? Compensator failure only? Crank Position Sensor failure causing the whole setup to run out of whack? I've never seen a failure like this! Anyone ever see this before? WTF?!!! dj, you're on! Thanks!

Hoist!

did you park it near Cybil??

 

[Gecko]

They all do that.

[djkak]

Before you freak out, this is not my bike! It's a friend's who's just out of W.....ty on an '07 96". Crank failure caused it? Compensator failure only? Crank Position Sensor failure causing the whole setup to run out of whack? I've never seen a failure like this! Anyone ever see this before? WTF?!!! dj, you're on! Thanks!

Hoist!

The photo doesn’t show the rest of the sprocket so I’ll assume that the spring retainer pictured was damaged by a broken spring or other component inside the compensator.

It is certainly possible that one of the sprocket’s internal components was defective and caused the pictured failure, but considering the history and what we know of the ‘07’s, it’s a safe bet that we are looking at an overload condition rather than a random failure. There is a strong possibility that the load capacity of the compensating sprocket was exceeded to the point of failure; but we already suspected that.

Changes to the 2007 powertrain resulted in a dramatic increase in the torsional shock loads throughout the powertrain, yet there were no changes made to offset the increased loads and things began to break in 2007. When these extreme torsional loads resonate through the powertrain, the entire powertrain is exposed to them, not just the crank. If this failure was the result of torsional overload, I would be surprised if the crank survived the ordeal.

There are differing opinions on how to manage the increased torsional shock loads; one camp feels that a more robust powertrain, including a stronger crankshaft would solve the problem. Another group believes that reducing the intensity of the shock load is a much more practical solution. I subscribe to the second group’s approach because these loads are a by-product of the powertrain’s configuration and are easily managed using common, time tested techniques.

It seems a little strange that you would be looking for a rehash of the previous powertrain chatter. Am I missing something?   

[jerdawg]

my 07 seuc had similar failure, 55 mph lockup, took wheel set out,bent tranny mainshaft, bent rear axle, 13 days before warranty ran out. had bike at dealer the week before complaint was clunk when i shut bike off, stealer told me it was a normal noise.

[Hoist!]

The photo doesn’t show the rest of the sprocket so I’ll assume that the spring retainer pictured was damaged by a broken spring or other component inside the compensator.

It is certainly possible that one of the sprocket’s internal components was defective and caused the pictured failure, but considering the history and what we know of the ‘07’s, it’s a safe bet that we are looking at an overload condition rather than a random failure. There is a strong possibility that the load capacity of the compensating sprocket was exceeded to the point of failure; but we already suspected that.

Changes to the 2007 powertrain resulted in a dramatic increase in the torsional shock loads throughout the powertrain, yet there were no changes made to offset the increased loads and things began to break in 2007. When these extreme torsional loads resonate through the powertrain, the entire powertrain is exposed to them, not just the crank. If this failure was the result of torsional overload, I would be surprised if the crank survived the ordeal.

There are differing opinions on how to manage the increased torsional shock loads; one camp feels that a more robust powertrain, including a stronger crankshaft would solve the problem. Another group believes that reducing the intensity of the shock load is a much more practical solution. I subscribe to the second group’s approach because these loads are a by-product of the powertrain’s configuration and are easily managed using common, time tested techniques.

It seems a little strange that you would be looking for a rehash of the previous powertrain chatter. Am I missing something?   

Thanks dj! Nah, not missing nuthin! A friend sent me the pic and asked me to get some feedback. The dealer said he never saw anything like it. Bike is just out of w.....ty and the dealer said he was still gonna try to get HD to do something since he's never seen this before. I didn't know if a bad crank would'a caused this or not, but I agree, the crank's gotta be toast now, if it wasn't already before! Skeery chit though! I'm now thinking of getting the replacement parts for my damaged SE Comp sprocket after seeing that, and having it reinstalled again PROPERLY, and hope it holds up!

Hoist!

[HD Street Performance]

I can't buy the new powertrain has any more shock load than any of the previous years assuming the riders are not lugging them which hurts parts on any of them.
Clearly the comp unit is weak and has a history of issues. The SE Comp unit seems to be better, well at least has some strong springs and we hope the thrust washer has a decent lifecycle, remains to be seen.
I would not be surprised if this crank was checked you would find excessive runout which is very likely the root cause compounded by the weak comp springs.
What were the symptoms prior to the failure, that would tell more than just seeing the ruined parts? How long did it run with those symproms?

[Hoist!]

I can't buy the new powertrain has any more shock load than any of the previous years assuming the riders are not lugging them which hurts parts on any of them.
Clearly the comp unit is weak and has a history of issues. The SE Comp unit seems to be better, well at least has some strong springs and we hope the thrust washer has a decent lifecycle, remains to be seen.
I would not be surprised if this crank was checked you would find excessive runout which is very likely the root cause compounded by the weak comp springs.
What were the symptoms prior to the failure, that would tell more than just seeing the ruined parts?

Thanks Don. I'm not clear on the symptoms prior to the catastrophic failure. He said he heard the noise when this occurred of course, but hadn't reported anything wierd prior. But he might not have been astute enough to notice anything leading up to the total failure. So I can't comment on that. I was only presented this pic, and asked if there might be a known cause for this type of failure. Now I'm personally torn between the simple stock setup I put back that explodes, and the SE comp setup which was destroyed on my bike once already, but not necessarily installed correctly the first time. Which would you use on a 125ft-lb, 120HP motor with no cush drive? I have the cush drive sprocket assembly, but when I took it out of the box and saw all those parts, I felt it would never hold up to my motor or riding style. Am I wrong about that cush drive? I've heard of them rubbers in there exploding too. Hmmmm.....What to do now?!!!

Hoist!

[aclass]

Had this happend to a friend just before Daytona this year.  07 Ultra with ~15K.   No collateral damage in the primary lucky for him.

[HD Street Performance]

So once again looks like the MOCO has a problem, that is unless these failures show up just out of the warranty period.  
Sorry I admit negative bias.
My 07 had the motor out before I even test rode it for "fixing".
I just can't get on the bandwagon and buy that the 07up drivetrain is any differant or making any more torque spikes than the earlier setup did. The gearing and the riders lugging do create that problem however. Many have suggested the HD 6sp with the old primary was a good gearing setup. I agree. It was not a power parasite either. The factory was putting out stock bikes with 103" motors and the drivetrains were reliable. Some saw police fleet use if I am not mistaken.
The fact is the MOCO for whatever reason screwed the pooch and didn't carry through with a redesign that was robust enough to insure a decent lifecycle, even for the folks that have stock motorcycles. Then to add insult to injury looked to technology to patch the problem with software and rubber in the back.
My 07 runs well and is fun to ride, now, but I shouldn't have had to do all that work and spend 1000s to get there. If emissions and noise were an issue I could get it to run even with that constraint and still have performance using the MOCOs own technology they use on the HDI bikes with active exhaust (and the ability to tune that through software), especially if I had access to their development and testing tools. So far I don't need to go there but I know how.

[djkak]

I just can't get on the bandwagon and buy that the 07up drivetrain is any differant or making any more torque spikes than the earlier setup did.

A longer stroke increases the leverage of the crankpin over the sprocket shaft. The lower numeric overall gearing increases the mechanical advantage of the drivetrain over the crankshaft. Increased leverage acting against the increased resistance results in substantially increased load potential throughout the powertrain.

The gearing and the riders lugging do create that problem however.

Effective throttle control has been used for decades to manage powertrain loads in modified, high output H-D’s; Hoist is an excellent example of this. Cybil’s powertrain wouldn’t last very long in the hands of a neophyte.

Then to add insult to injury looked to technology to patch the problem with software and rubber in the back.

From my perspective, this argument was made and put to bed decades ago. Springs, rubber couplings and dampers have been used in automotive and other applications to manage high torsional loads longer than many of us have been walking this planet.
 
My argument is that issues with the ’07 BT’s are the result of destructive torsional vibration. The challenge to manage this type of load is nearly as old as the reciprocating piston engine; as are the solutions.

Since early 2007 Milwaukee’s efforts to manage these extreme loads appear successful. The solution makes good sense to me when compared to similar solutions in other piston engine applications. Beyond educating the Rider on effective throttle control technique, the challenge still remains for folks that are running modified, high output H-D Big Twin’s.

This is simply my humble opinion and if it doesn’t pass muster when filtered through each reader’s background and experience, then it makes sense to take a pass or pushback.

[Buy early]

For the neophytes among us (no offense taken, just a statement of fact), what are the aspects of effective throttle control? When I get to New York and find myself on one of Hoist's highly modified steeds, I don't want to be responsible for trashing the powertrain.

[Hoist!]

For the neophytes among us (no offense taken, just a statement of fact), what are the aspects of effective throttle control? When I get to New York and find myself on one of Hoist's highly modified steeds, I don't want to be responsible for trashing the powertrain.

Don't be worrying about that Mark! You never go over 85! All my bikes aren't even breakin a sweat yet at that speed!

Hoist!

[Buy early]

Appreciate that Hoist but it doesn't keep me from wanting to learn how to ride more effectively. The request remains - what is effective throttle control?