Sticky crank?

JimBob,,ya just think it's together,,,it ain't quite together yet.

You can't Really PUSH a ball Bearing main-bearing engine together.

The bearings have a radial clearance in them which allows the Inner Race to drift Sideways.

So when you PUSH a Crank into the Bearing,,,

You cannot get that slack out.

Result is that the INNER Races are not fully seated to their home position.

The STIFFNESS You feel is due to the Roller Balls being Pinched between a pair of Offset Raceways in each bearing.

Exagerated to illustrate the point>>>>

Measured according to Main Bearing RACEWAY centerlines,,,

You have a 5" Wide Crank wedged into 4" wide Crankcase.

That OFFSET between the Inner & Outer Races is putting a Bind on the Roller Balls.

Tapping on the crank is Still only Pushing.

You can Usualy NOT drive a crank thru far enough to fully seat INNER race against Crank's flank/shoulder.

Cuz when You Drie the crank towards the bearing,,,the Inner Race Recedes into the Brng Assy---it Floats Sideways THRU the Bearing,

And your only pounding the Races into the Balls & Balls into the races.

Dimples are Great on Girls,,,

Not so great on Main Bearings.

....................................................

You must PULL the Crank thru the Bearing.

And you must restrict all lines of force & all load AWAY from the Balls,,,and ONLY on to INNER RACE.

Yamaha makes a Snazzy Special Tool.

You can too.

Actually,,on PRIMARY side,,,all you need to do is Torque the Pinion Gear on R/H side of Crankshaft.

That pulls direct on the Crank,,,and all the force is restricted to INNER RACE.

As you Tighten the Nut,,it PINCHES the Pinion Gear between the NUT and the Bearing Race,,,,and pulls the crank THRU the Bearing with NO LOAD whatsoever on anything else.

On the Timing Side,,the Mag side....

a)You must have Crank Seal REMOVED

b)Use a length of pipe which will Barely Fit over crankshaft,,,and Shoulder on the exposed Inner Bearing Race.

c) The Tube's Length should be Long enough to leave about Half the Crankshaft thread Exposed.

d) You'll need a Washer or "plate" to Fit Over the Threads,,,And large enogh to shoulder on the Tube.

e)Use the Flywheel nut to PULL the Crank THRU the Tube>Inner Bearing Race

Make any sense?

To your Main Bearings it sure does!

**CAREFUL with Sizing of the Puller Tube.

If it's Too Large a diameter--there's a risk of it slipping Over the outer race,,,and pressing into the Ball Retainer on the Bearing.... which is real bad news

After having both sides pulled thru their bearing and their inner races fully seated against crank,,,,it should be very,very free spinning.

When it's Right,,,Crank will roll itself over due to it's counterweights alone.

Or,,,they'll "RUN" for a several revolutions with a Big Rubber Band connected to the Rod end to give a small boost on Upstroke.

Spin it,,,the counterwights and rubber band keep it going.

They are incredibly free-wheeling when set up right.

Only hope of getting it RIGHT is by Pulling the Crank thru the bearing.

Very Rare to be able to push one thru into correct position.

Good Luck with it,,hope that helps.

You are binding,are the bearings seated squarely.All surfaces need to be absolutely clean.The bearings have to be seated in there bores completely and square.The case halves need to be exact..001 to .002 off is enough to bind a bearing.If the cases are bolted tight already,take a rubber mallot or block of wood with a steel hammer,and hit each end of the crank sharply to see if it loosens up.