I used a 2" galvanized pipe inside 2" pvc coupling and cut it down to a 1 and 1\4 inch. The galvanized pipe just gives it more strenght. 1 and 1\4 inch seem to be just right for what needed.

 

i did mine last year as well...used a bunch of hose clamps to compress the spring ..no plaastic body parts removed at all....compressed them enough to make the spacers fit in and all done. easy job...not sure how the instructions read but i split the spacers and overlapped the joints between the pipe and the outer fitting