Here's a great 4 page article covering the problems with the TC engines INCLUDING the twisting cranks (page 2).
Twin Cam Engine - Hot Bike Baggers Magazine
Here's a snip from the article.
Twisting Crankshaft
A serious Twin Cam problem that is seldom talked about is crankshaft shifting. Under hard deceleration, acceleration or burnouts, the Twin Cam's pressed-together crankshaft can twist out of true, sometimes as much as .030 inch or even more in worst circumstances. An ideally trued crank should be trued to within .001 inch. A crank severely out of true causes the end of the pinion shaft (right side) to wobble severely. Early warning signs are loud noises from the engine's gearcase area, ticking lifters and oil puking out of the breathers. The result is catastrophic damage to the oil pump and loss of oil pressure and scavenging. For starters, the crank, oil pump, camshafts, cam support plate and cam drive mechanism need replacement. Furthermore, debris from the damaged parts circulates throughout the engine, trashing cylinder walls, pistons, lifters and anything else in its path. The oil tank also ends up contaminated and requires cleaning. If you are on warranty, you may be lucky enough to get a replacement engine, never really knowing what exactly went wrong or why it went wrong. But the problem is waiting to bite you again, because your new engine has the same flaws as the old, damaged engine. On the other hand, if you're one of the unlucky ones, you get a big repair bill.
Twin Cam Engine - Hot Bike Baggers Magazine
Here's a snip from the article.
Twisting Crankshaft
A serious Twin Cam problem that is seldom talked about is crankshaft shifting. Under hard deceleration, acceleration or burnouts, the Twin Cam's pressed-together crankshaft can twist out of true, sometimes as much as .030 inch or even more in worst circumstances. An ideally trued crank should be trued to within .001 inch. A crank severely out of true causes the end of the pinion shaft (right side) to wobble severely. Early warning signs are loud noises from the engine's gearcase area, ticking lifters and oil puking out of the breathers. The result is catastrophic damage to the oil pump and loss of oil pressure and scavenging. For starters, the crank, oil pump, camshafts, cam support plate and cam drive mechanism need replacement. Furthermore, debris from the damaged parts circulates throughout the engine, trashing cylinder walls, pistons, lifters and anything else in its path. The oil tank also ends up contaminated and requires cleaning. If you are on warranty, you may be lucky enough to get a replacement engine, never really knowing what exactly went wrong or why it went wrong. But the problem is waiting to bite you again, because your new engine has the same flaws as the old, damaged engine. On the other hand, if you're one of the unlucky ones, you get a big repair bill.