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I'm Stumped! Shorter front forks on 1100 help required

Posted: Sun Mar 31, 2019 9:27 pm
by Uncle Bob
The Swiss Katana is a right pain for me to get on the centre stand, which I had mentioned before. After investigation and comparison to my other 1100 it was due to a slightly smaller rear tyre profile and the front forks appearing to be about 2cm shorter.

Sparki sent me an image of a mod that normally achieves this:
GSX1100 Shorter Forks.jpg
So I have finally taken the frontend off today and stripped down but for the life of me I cannot see why they are about 2cm shorter. I had a spare (knackered) set of 1100 forks which I stripped for comparison. I have taken some images. Can anyone tell me how the Swiss Kat ones are 2cm shorter when inside they look the same - see images below:

Ok the sliders are the same so I have just shown the top here (Swiss top, Spare 1100 below). Clearly you can see the Swiss ones are shorter.
GSX1100 Forks 1.jpg
Here are the damper rods as removed (Swiss top, Spare 1100 below) - look the same and no spacer as Sparki's image would suggest there should be.
GSX1100 Forks 2.jpg
Here are the Stanchions as well (Swiss top, Spare 1100 below) which are identical.
GSX1100 Forks 3.jpg
Forks tops, top spacer and springs were also the same.

I cannot for the life of me see why the Swiss ones are about 2cm shorter (top of slider to top of stanchion).
Can any see what I have missed?

Thanks

UB

Re: I'm Stumped! Shorter front forks on 1100 help required

Posted: Tue Apr 02, 2019 12:05 am
by johnr
might be in the actual fork lower leg itself. possibly from a model with a different size front wheel, is it an sd model? cos they came with either a 16 or a 19 inch wheel.

Re: I'm Stumped! Shorter front forks on 1100 help required

Posted: Wed Apr 03, 2019 1:57 pm
by Uncle Bob
Could someone with an 1000, 1100 or 750 and a standard front end measure the distance from the top of the slider to the top of the fork tube for me. Preferably while the front wheel off the ground if you can get someone to sit on the back!
I have a feeling some user error may be involved and that measurement would help me confirm it.

Cheers

UB

Re: I'm Stumped! Shorter front forks on 1100 help required

Posted: Wed Apr 03, 2019 2:26 pm
by stockcar
i have a set lying here that i'm fairly certain are GSX1100 and measure 38.5cm (approx 15") from the top of the outer fork leg casting to the top of the chrome tube

Re: I'm Stumped! Shorter front forks on 1100 help required

Posted: Wed Apr 03, 2019 5:40 pm
by Uncle Bob
Cheers Stockcar. On one of my 1100's it's about 46 (ish) cm and the other they are 43.5cm, so that confuses me a tad unless they are not 1100 Katana.

I wanted to see what another 1100 Katana (though the 750S1 and 1000 would be the same) is. I suspect (hoping) they will be the nearer the 43.5cm, and the 46cm ones are the ones that, shall we say, have the user error! I would know I have the correct parts then. If someone else has 38.5cm like you then I have an issue on both bikes :-(

Hence it would be handy for another measurement from someone else. Thanks UB

Re: I'm Stumped! Shorter front forks on 1100 help required

Posted: Wed Apr 03, 2019 6:21 pm
by stockcar
Those must be odd ball ones i have at work, been out to the garage and measured the Kat and they are 43.5cm so match what you have there

Re: I'm Stumped! Shorter front forks on 1100 help required

Posted: Wed Apr 03, 2019 9:17 pm
by Kryten
Hi Bob.

I have a couple of spare sets of forks in the shed.

One set is a Kat set and the others are off an 1100E. The non Kat forks are shorter and have an odd damper adjustment on the lowers.

Typically I have just started my shift up in Sunny/Soggy Lincs.

If you are still scratching your head when I’m back I will do some measuring for you.

Re: I'm Stumped! Shorter front forks on 1100 help required

Posted: Thu Apr 04, 2019 7:26 am
by PaulD
I can measure my forks if it helps?
Obviously they are attached to the bike but if you want an external measurement I can do it.

Re: I'm Stumped! Shorter front forks on 1100 help required

Posted: Thu Apr 04, 2019 9:14 am
by Uncle Bob
If 1 more person could that would be good, just to confirm the 43.5cm Stockcar gave me. External and on bike is how I did one set of mine, though I did jack up under engine to push it on to back wheel to get rid of the sag on the front (I suspect these are the ones that are wrong as they measured about 46cm!).

Thanks

UB

Re: I'm Stumped! Shorter front forks on 1100 help required

Posted: Thu Apr 04, 2019 5:37 pm
by stockcar
Mine was done with no weight over the front.....