I have a Saito 45 in a trainer the motor is old but still new (sat in the box) I have had the problem that after my last flight which resulted in an altercation with the ground. Anyway the results is that the motor was harder to turn over. I removed the back plale ,the moment the screws were loose the binding was eased. I removed a very slight amount off the inside of the back plate and replaced it all is fine now. Has any body had this problem with saito's

You have knocked the crank rearward slightly, best fix would have been to remove the prop, prop driver and reassemble to reposition the crank forward.

Cheers

If you had the rod off, sounds like it's on backwards.

Could also be that you punched the crank in just a small amount with the terrestrial encounter.
If it turned fine before, there was room for all the parts.