what I have for the spring is this, 33 coils, ID.500, wire size .115, length approx 9 inches, the spring can be spaced up quite abit (1/2 inch?), I'll space up a stock spring and see what happens....spaced a stock spring up .270 thats about all it would take, with a new seal it only did a bout 550-560 and it was smoking quite a bit. I don't think you will get it to 700, stroke etc is just not there.....haven't ried everything possible but.....almost forgot, Canadian model, has to be under 500, better spring will bring it up to 700 possibly, wonder what the spring is in the B-11.......