The MOCO really dropped the ball, when they went to all the effort to build this motor and not weld the crank, IMHO.

It doesn't matter if the wheels are made out of titanium, press fit pins will "give" if jerked around enough.

If welding was unnecessary, then no one would do it.

that said, as long as you don't like to drop the clutch from a standstill...do burnouts etc., it will probably survive.

But why take the chance? the engine is already out, and is too easy to tear down when sitting there on the crate.

Do what you wnat....but I'm not going to do a full on engine and not weld/true the crank and add the TIMKEN lefty bearing along with Torrington cam bearings.

~Joe

 

I have the SE Pro Stroker 4 3/8" crank in my 117" while its a lighter setup made by Jims for Harley it still has a pressed in crank. Any reputable engine builder will you tell its a crap shoot on these 07 and newer cranks. Adding to the fact that the 120" engine uses a 4 5/8" stroke which is longer ( more thrust outward from the circle rotation) then the 4 3/8" stock stroke on a 96" or 103" you increase the chance of twisting the crank pin. Even S&S had a list on the engine they produced that showed the longevity of having a long stroke and big bore.

If money is no object then by all means spend it how ever you like.

 

Next time you guys get a chance, hold a set of wheels in your hand in the forward direction of the motorcycle. The left wheel is tied to the rear wheel, the right wheel is not.

When you let the clutch out, the right wheel wants to move, the left wheel has the rear wheel of the bike trying to keep it from moving.

What it mean is...there is a twisting force, and if the force is great enough, the wheels with shift or scissor.

When this happens, when the runout gets too far out, itd will wear on the oil pump.

Then, your oil pressure will begin to drop.

At some point, through oil pump failure, or a lack of oil pressure, etc., the engine will be toast.

So, if you have an oil pressure gauge, it doesn't hurt to know what it normally reads and occassionally glance at it, as a gauge to what is going on in the crankcase.

but what do I know....

~Joe

 

obviously a lot more than the average non-wrencher rider. Thanks for the interesting take on this.

 

Good point mine is in the shop now with2600 miles the flywheels shifted and wiped out everything oil pump pistons and cyclinders

 

That sucks

 

I don't disagree with any of the points you and Traveler have made about the 120R crank and I am not arguing the benefit of having any crank welded. Agree on the "crap shoot" with the '07 and later cranks but we are talking about the SE Pro Stroker crank which is a cut above the OEM cranks.

Just saying that the SE Pro Stroker crank is a better unit than the OEM crank, ligher assembly withi pins fitted to tighter tolerances. If the motor is not abused, odds are that the SE crank will hold up just fine.

I had the Hoban treatment on the crank in my 107" motor but the crank in my 95" motor (104TQ/96HP) is not welded. The little 95" motor ('05 FXSTD) had .0025" runout when I built the motor and installed gear drives; new hydro kit was not availble then. Nearly 20K hard miles on the build and runout is still .0025".

If I bought the 120R crate motor, I would not go to the trouble and expense of tearing it down to weld the crank. If I was concerned that the crank was an issue, I would buy the kit, have the crank welded and assemble. I am not trying to convince anyone of anything. JMHO, everybody else is entitled to theirs.