One for you Scotty. I have a 07 Dyna, there is info out there about crankshaft runout on 07 TC's being excessive and destroying oil pumps ect. WTF. If you are changing cams and check runout and its out of specs (which Harley have amended for 07 up) what do you do? Will installing Timken bearings help. Are some trueing the crank and welding both sides together?? Can you explain it in laymans terms mate. And should you get it checked before warranty expires?

 

Gibo

welding the crank is pretty risky, they can warp but the welder wont take responsability if it does, welding aint really needed if ya not planning on goin much over 100hp, ive seen 1 crank with more than about 0.004" in the last 12 months, and that crank was a stage 1 built 07 flstc with 0.020" n blew the oil pump. hd may do it good will after warranty has run out.

Thanks Scotty, food for thought, and bye the bye there is no way I would give anyone a hard time when giving advice. My knowledge is very limited in regards to Harleys so I value all advice...especially yours. I'm not trying to blow wind up ya arse, thats just the way I r.

Say for instance you are changing cams and you check the runout and its say between15 and 25thou what would you do ?  Or should I say at what deviation would you pull the crank?? Gets me why they dont true/weld the fuckers before fitment, I would gladly pay the extra. Is there a problem with both softail and Dyna,, arnt softail cranks balanced??

Is there a trend on the amount of k's these cranks are causing problems at ? I've done over 20,000, oil pressure is fine and no more than usual vibes.

 

Gibo

Love my Bob

Yeah was thinking the same. Thanks for the info Scotty, thanks also to AKA for your input.

Scotty:

Checked the '07 Ultra last winter during the cam upgrade, and she was at .00325" with the camplate on. ~.0034 with the camplate off.  So far, seems to be holding it's own.

BTW:  Ordered one of the Fueling RO Checkers through Herko; should be hear in a week or two.  Going to take it to a friend/master machinist for specs.........

Your right, the '05 up Cranks are a crap-shoot.  IMO, run 'em till they puke!

 

 

Makes me happy I have an EVO...

Most of the talk I have heard regarding crank scissoring seems to centre on surprise that a crank in an engine with relatively low output has shifted, and concerns that a crank in a higher output engine may well be more likely to shift.
Under acceleration, resistance to the pinion side wheel turning is present, but relatively minimal(turning cams, oil pump, etc), whereas resistance to the sprocket side wheel is considerably greater, running through the drivetrain, right down to the tyre.
But there is nothing in that dynamic to make the flywheels want to turn at different speeds, or to necessarily induce shifting. Under those conditions, the pinion wheel merely follows the speed of the sprocket wheel, and the size of the engine, and relative power output, has no bearing. The very lack of resistance to the pinion wheel ensures that it is happy to follow the pace of the sprocket wheel. The cranks I have seen have very high retention at the pin, and are incredibly difficult to move(well known fact, I think), even after scissoring up to 0.050.
So under acceleration, force is applied evenly to both wheels. Resistance exerted upon the sprocket wheel, does not generate any change in dynamic in the other wheel.

Once the flywheels have reached higher revolutions, there is a great deal of inertia in the wheels. Under these conditions, the pinion wheel now has the ability to think for itself. Just because the sprocket wheel is caused to slow, does not mean that the pinion wheel will want to slow. If the throttle is closed, there is a force exerted on the sprocket shaft, more so than the pinion shaft, and it is true that in a higher compression engine(not larger capacity) that this force in increased, but given the relatively robust construction on the crankshaft unit, it is believable that these forces could be endured without failure over a long time period(excluding manufacturing defects, as opposed to design faults).

However.... should, for whatever reason, the sprocket shaft experience unusual deceleration via the drivetrain, then the pinion wheel most certainly would not share that dynamic, and would want to keep turning, due to unchecked inertia. Under these circumstances, only the press fit retention of the flywheels onto the crankpin will prevent scissoring, and has been clearly seen on many occasions, this is sadly often not enough. The mass of the wheel(weight, stroke, etc) is the factor here, not the power output of the engine, nor the capacity. A likely culprit for causing this situation to occur, though not the only one, is the rear brake.

High revving, high power, gentle decel, is unlikely to give problems(or less likely).
Low power, medium revving, jumping on brake, slamming throttle shut, etc, etc, may well give problems(or just as likely)
The greater the mass(put simply, weight over stroke) the more likely it is to experience difficulty with retention, but TC 88 are not immune, as I am sure we all know of failures there as well.

Welding the pin has become common practice, and has actually been the preferred solution to these crank design types for as long as I can remember, and I am sure well before that too.
Seeing as HD do not intend there cranks to ever be disassembled, it might be reasonable to conclude that they have nothing to lose by utilising a weld/pin/whatever strategy to better retain their flywheels.

DR