Hi I have a Novarossi 21-5kt engine when I am tightening the flywheel up tight on the collet the crank seems to be binding on my rear bearing not letting it spin freely any suggestions would be great cheers!

Is the collet going too far into the flywheel allowing the flywheel to hit the engine block. I had an rb engine with that problem & put 1 shim behind the collet (between collet & bearing) & it is now fixed.

No because I have tried it with the internals out and when I tighten the flywheel I can see the crank pull in to tight on the rear bearing

Just put a shim behind the collet.

Did you by chance just replace the bearings? If so you might not have the inner bearing seated all the way. Had this happen to me.

I have just bought the crankcase off ebay bearings installed whats the best way of fix if I have to take the bearing out whats the best method to install it again beacause I have had big problems installing novarossi bearing thats why I had to replace the crankcase this is my second