Yeah Chain, the top spring and bottom springs are preloaded as you tighten the crown nuts. As the fork travels through its compression stroke the top springs can often become totally slack but keep the fork from slamming back down on the rebound stroke. It works surprisingly well at the low speeds on a bicycle but could be terribly dangerous on a 100mph chopper. The other factor, with a motorcycle primarily, is the overall length of the fork. As they get longer the tubing wall thickness really needs to be increased to maintain strength but that adds much more unsprung weight which also effects handling and steering feel as speeds increase. But like I said on a bicycle this is a mute point but expect the fork to become a boat anchor if its much longer than say 8" over a stock length fork.
I've built many of these forks in both applications, motorcycle and bicycle. My suggestion is if you really want to go with a long chopper fork, also look at the Girder fork designs as these can be made lighter overall and in my opinion work far better than a pogo stick.
Just my .10 cents.
Later Travis
