Tight spot on crankshaft

Ok, I have an 81 GPz1100 engine I am putting back together. When I installed the crank intot he upper case and torqued down the main bearing cap the crank has a tight spot while turning it by hand. The tight spot moves around it is not always in the same spot. I thought it was a dirty bearing so I took it back apart and cleaned everything over and over. put it back into the case and same problem. Without the bearing cap the crank will spin nice and smooth. When I torque the cap down, 18 Ft. pounds the crank will sometimes turn smoothly for a while then get tight. When that happens I can leave the crank in it's tight spot and take the bearing cap off. With the bearing cap off the crank will remain tight until I turn it then it will free up and spin smoothly. When I tore this engine down to do the rebuild I checked the crank prior to taking it out of the case and it was fine.
What I think happened is, I stored the crank in a box and stored it on my garage floor. When I finally got around to putting everything back together, 3 years the crank became slighty warped due to the way I stored it. Any ideas?

maybe stick it in some v blocks to make sure its straight,is it sitting in the dowel pins of journals the way its supposed to?

Yes, all the bearings are sitting in the pins correctly. I'll try the V block trick.

are you torquing from inside out or outside in towards center of crank?

i dont think it could warp from sitting, but u could get rust in the bearings.
it is odd that it isnt in the same spot though.it seems like the crank must be out of place with the pins or cap somehow ? could the cap be on backwards ?

If it was a tight spot on the crank it seems there would be some scuff lines on the bearings.
Good luck.

roller bearing crank

Impossible to warp from sitting unless you parked your truck on it.

I tried all different ways to torque the cap. The cap is on correct, has arrow showing forward stamped on it. The bearings all feel nice and smooth by hand. The weird part is sometimes the crank is nice and smooth for 10 or more revolutions then all of a sudden it gets tight and will not smooth out until I loosen the bearing cap and then turn it, that frees it up.

i wonder if you got some moisture/rust in a bearing from it sitting,i lost a mkII crank that way years ago in a humid garage

Could you be getting some crank walk and that is putting the crank up against a crank support or tight against the case, etc. and then that causes it to get tight? Just trying to think of any possible causes.

try prying over on end of crank? thrust washer?