shortening usd/cartridge forks length/stroke

[03gixxerpilot]

how dose one go about shortening the length/stroke of usd cartdrege forks

I have looked at them to see how it is done, and i think i have sused it out, but i would like to here form others what they do befor i embark on this corse of action.

this will be for a drag bike'

any help would be appricated

Cheers Clive

[03gixxerpilot]

schematic of the forks i am using, k1 gixxer 750
http://i4.photobucket.com/albums/y137/03gixxerpilot/web%20shit/21.gif

[Dynomutt]

Shorten the spacer tube on top of the spring by the required amount, then shorten the damper rod by the same amount, you will need to re tap the M10 X 1.25mm thread on the end of the damper rod so the locking nut and top cap screw back onto it. Depending on how much you are shortening the forks you may also need to shorten the stanchion as well, as the travel will remain the same you may find the stanchion hitting the underside of the top cap.When you disassemble the fork wind the rebound adjuster on the top of the fork cap all the way in, otherwise when you reassemble the forks you'll lose the adjustment range.
You'll also need a means of compressing the cartridge to access the locking nut on the damper rod, I have a special tool which I made which holds the fork bottom and clips over the spacer tube and then winds down and compresses the spring to reveal the locking nut.
You'll need to calculate the reduction in oil quantity, stock forks take 512ml of oil, measure the airgap prior to draining them and then refill to the same airgap when shortened.

[Dynomutt]

You'll also need to shorten the thin internal rod which adjusts the damping by the same amount as you are shortening the damper rod. If you want to reduce the travel then the easiest way is to fit a harder spring

[03gixxerpilot]

thanks for the info, i will look at the forks today if i get a chance, what you are saying is pretty much what i had figured, i have lowered the tubes as far as i can but need to reduce the height of the bike by a further 2inches to get it to the height that i want.
so reducing the length is as nessasary as reducing the storke, obviously if i reduce the length i also need to reduce the stroke as well.

Cheers
Clive

[Dynomutt]

Yes you will need to shorten the top of the stanchion, but do not cut them further than the oil bypass hole. You will also need to measure up inside the fork outer tube to the top sliding bush, to make sure that the stanchion engages correctly with it when fully extended, you may also need to add some form of bump stop to the underside of the top cap incase the forks bottom out. You will need to fit heavier springs to reduce the risk of them bottoming out, although you are shortening the forks the stroke will remain the same which means the forks will have a greater risk of bottoming out. Reducing the stroke is a much more involved process than simply shortening the forks. If the bike is being used on the strip then the heavier springs shouldn't be an issue.

[Large]

There's a way of doing it by adding a spacer that means you don't have to chop anything and everything can be put back to standard if needed..

It was explained to me a few years ago, but I saw something shiney and lost concentration

[03gixxerpilot]

mutt thanks for the info, i have spent the afternoon at the workshop and figuard that all out, just got to get the forks out of the srad and do it. (had a set of stuffed tl forks to sus things with)

Large that is funny as LOL

[Dynomutt]

You could always just strap the forks down like a lot of guys do on the strip, it saves an awful lot of messing around, and means you can go back to stock easily.

[03gixxerpilot]

LOL i guess it is a personal thing, but i dont like lowering straps.

i have the orignal front end for it if i want to go back to stock. as it is, it has a K3 thou front end in it, that will go into the srad to replace the ones that i am going to steal out of it to do this with.

[Booster]

http://www.suzukihayabusa.org/forum/index.php?topic=135724.0

Try this Clive, the reversable spacers are easy to do.
Combo of shortening and straps lets you dial it in to suit track conditions

Thanks Booster. Bloodu good link.