Kawasaki engine hard to turn over

I have a Kawasaki FH601V twin that was dumping oil out the top due to a worn crank and journal. I replaced the crank with a good used one, new bushing, rings and seals/gaskets. It ran great for an hour with small oil leak at the top again because I did not get the oil seal installed correctly. I noticed the crank is hard to rotate (can't rotate by hand) as I was installing the new oil seal and setting the ignition. I removed the spark plugs and it is still difficult to rotate. I readjusted the valves but it made no difference. It appears to be most difficult to turn at the bottom of the stroke on cylinder 2.

Do I need to tear into it again and if so what should I be looking for?

Thanks!

These other guys will correct me, but I am thinking some of the FH engines used a sump gasket and some (the last ones) had the sump sealed
to the crankcase with RTV. IF it had a gasket, I am thinking that you have to leave a washer (maybe two) out if you go the RTV route. I
can't remember if the washer was on the crankshaft or on the camshaft.

I don't know any other way but to take it apart again, but do it in stages. Remove the clutch (assuming you installed one) and re-test.
(Confirm that your tightness isn't in the clutch). Check the air gap clearance of the ignition modules. (You don't want one of them
dragging on the flywheel) Remove the engine, loosen the sump bolts a turn or so and allow the sump to spring away from the crankcase if it
wants to. Test again. Beyond that, check the rod caps and crank for any metal transfer or scoring. I am guessing you will have to remove
the pistons, so check the pistons and the cylinder bores for any excess scoring.

Since you said you put a new bushing in the crankcase, you may have to do a test assembly with just the crank and sump on there to see if
the bushing is misaligned.

Just for my info, how may hours on the Kawasaki? I don't think I have ever seen one where the crank and bushing were totally worn out.

You probably also know, but that crankcase breather plate on those engines tends to leak after it gets a lot of hours on it. There is an
update cover that may work on your engine that is thicker and has longer bolts.

Thanks for your reply.

The engine has 550 hours approximately. I read that the early crankcase design only relied on the oil passage through the crank to lubricate the top bushing and over heating causes damage. There were signs that it ran hot.

The only RTV I saw during disassembly was a little on a valve cover in addition to the felt gasket. I cleaned it all off and used a new gasket with no issue. This is the project that keeps on giving I guess.

Here is a picture of the top of the old crank.