USD Forks. What way to go??

[hart_57]

Well the title says it all, I almost have all of the parts I need to build my new streetfighter, except the front end. I know the Busa swap is very common as well as the GSXR, I also know that it is fairly simple to swap to the ZX7R, I've seen an R6 front also put on a Kat. I'm sure there are more out there that can be done as well.
I can get triple trees custom made for cheap. Ohh and I swapped the rear shock for one off from a RF900 if that makes a difference on what set I should be looking for.

So my question is, what is your opinion on this, what is going to be the most affordable and straight forward approach to doing a USD swap.

Thanks for any help in advance

[arsenic]

Anything but the Hayabusa

[blitz2190]

for probably around the same price(if not less) you could also do the race tech emulators, just another option if your looking for performance

[cintidude04]

If you can get custom triples made cheap then you can use almost any fork you like. In the process of that now myself.

[Nut-Nut]

I only have experience with one... see the link on my Sig... and good luck with the swap.

[92GSX750]

You need to take into account fork length when doing this. Alot of the USD forks are alot shorter than the Katana forks, pick a set thats too short and you height and trail # will suffer. Then you also need to look at the spring rates unless you plan to re-spring them.

K6/K7 GSXR 600/750 forks are 738mm long, have a 1.00/270 spring rate and would be my first choice

99-07 Busa forks are 725mm long, have a 0.85/250 spring rate and would be my second choice

Since your going to have custome triples made, I would sit down and do some math for your steering stem offset that way you can dial in your trail

[scottynoface]

pick a set thats too short and you height and trail # will suffer

Or benefit, shorten them up a bit to quicken up the lazy turn in.

[92GSX750]

It will help up until a point, and then I think it will be too quick. The Busa forks lowered all the way in the triples on my Kat have my trail between 3.9"-3.95". Pick a set of USD's that are shorter than the Busa's and you will be stuck with a trail figure a lot less and not be able to change that without slamming the rear end.

[scottynoface]

It will help up until a point, and then I think it will be too quick. The Busa forks lowered all the way in the triples on my Kat have my trail between 3.9"-3.95". Pick a set of USD's that are shorter than the Busa's and you will be stuck with a trail figure a lot less and not be able to change that without slamming the rear end.

True, moderation is key.

[GSXFJim]

The zx7 stem is going to be too short and too large in diameter... I know I've adapted 3 sets of zx7 forks already. if you want to run the zx7 stuff.. just replace the stem and your done.
like this...
New one on the top and old on the bottom..

[hart_57]

There's a bit more to this than I thought....

@GSXFJim, How are the ZX7 forks on the kat?

[GSXFJim]

The zx forks went on a kz900, gpz750 and a kz650 respectively and after knowing what I know now about them, I'd opt for a set of gsxr or r1 units instead if i were to do it again...
I've done one set of '99 gsxr forks for a kat. I currently have a set of '91 usd gsxr forks on my kat, to be honest, if I had to do it again, I'd do emulators and new springs in the kat forks, mine work ok.. but after the hassle of getting it installed and set up, the emulators would have been easier. I took Tmods advise did emulators and pre-load adjusters on my wife's sv.. and it made a world of difference.





My kat

[blitz2190]

Plus, according to another thread on here that i can't find now, the kats actually have less unsprung weight

[hart_57]

what is it that you know now that would make you go for a different set?