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.