GSXR 1100 fork extension to fit 1100 Kat

[John Kat]

I decided to fit a GSXR 1100 RSU front end to my GSX 1100 SZ Kat.
The good news is that this fork uses 43 mm diameter stanchions ( compared to the 37 mm OEM) and it's a straightforward fit except for the lockstops.
The bad news is that it's too short at 745 mm vs 800 mm for the Kat.
Given that the matching front wheel is also smaller at 17" versus 19", I went for an extension of 100 mm.
This might seem a lot but I'm also planning to use the original GSXR clip-ons that fit above the top yoke.
The exercise proved a little more difficult than I thought as you need three coaxial tubes to keep the spring preload and the damping adjustment.
Here are some pictures

 

[Billy Ricks]

Nice work. The conversions are definitely easier to do on the bikes with 16" wheels. I used the same fork from an '88 750 and it was like night and day in the handling department. I've since gone with '95 forks.

 

[salty_monk]

Nice! Did you turn those up yourself?

 

[John Kat]

Helas no!
I'm not equipped to do so
In the meantime I've worked out some maths to determine a bike's new geometry after changing the front forks.
I'll open another thread on this subject.
The results are somewhat surprising

 

[7981GS]

$$$$$$$$$

Win a local lottery lately?


Daniel

 

[posplayr]

Are the Kat forks that long to accommodate the clip-ons? Most of the GS1100E forks are only about IIRC 1/2 inch longer than the 86-88 GSXR1100 RSU forks.

If you want I have a spreadsheet that details out most of these calculations with inclusions for both front and rear tire/wheel sizes forks length, fork offsets, rear shock length trail etc......

I decided to fit a GSXR 1100 RSU front end to my GSX 1100 SZ Kat.
The good news is that this fork uses 43 mm diameter stanchions ( compared to the 37 mm OEM) and it's a straightforward fit except for the lockstops.
The bad news is that it's too short at 745 mm vs 800 mm for the Kat.
Given that the matching front wheel is also smaller at 17" versus 19", I went for an extension of 100 mm.
This might seem a lot but I'm also planning to use the original GSXR clip-ons that fit above the top yoke.
The exercise proved a little more difficult than I thought as you need three coaxial tubes to keep the spring preload and the damping adjustment.
Here are some pictures

 

[John Kat]

I measured the lengths of the various Suzuki forks here:http://www.thegsresources.com/_forum/showthread.php?t=186805
The forks I want to fit to the Kat are the GSXR 1100 K RSU 43 mm that are shorter than the 87/88 model.
Those forks had the clip-ons above the top yoke instead of below on the Kat.
I want to keep it that way to help my back
Your spreadsheet would be very welcome ( I don't mind the maths but I'm no good at spreadsheets...)

 

[John Kat]

I finally got the extended GSXR 1100 forks on my Kat
I haven't tried it yet but here are some pictures.

 

[jwhelan65]

Great job, how is the clearance now compared to stock?

 

[John Kat]

I posted the different fork lenghts here:http://www.thegsresources.com/_forum...d.php?t=186805
The GSXR fork has been extended by 100 mm as the original fork is 800 mm long compared to the GSXR that's only 750.
The extra 50 mm are to compensate for the 17" wheel versus the 19" and the fact that the clip-ons are on top of the yoke.

 

[salty_monk]

Looks like you have plenty of room to put a riser plate under those clip-ons too. Perhaps add 5mm each birthday or something

 

[John Kat]

Looks like you have plenty of room to put a riser plate under those clip-ons too. Perhaps add 5mm each birthday or something

Right you are SM
You really had to be a hard core biker to buy a 1100 Kat in those days...
Strangely enough that must be one of the reasons it became a collector?
It's a bit like the E type Jag, far from a perfect vehicule but a real myth...
I know because I restored one a long time ago and sold it after driving it for a couple of months.
The Kat is for keep don't worry!

 

[Guest]

You are going to love those new front brakes.