Front end swap

[Guest]

I'm looking into the feasibility of swapping the stock front end of my '83 GS1100e with a later GSX-R front end with a 17" wheel. How would this change affect the handling and overall "feel" of the bike?
Thanks,
Bix

[niclpnut]

Its been done lists of times. Search gsxr conversion. It definitely lightens up the front end and quickens the steering.

Need to do the rear also so you have radials front and back.

Nic

[John Kat]

I'm looking into the feasibility of swapping the stock front end of my '83 GS1100e with a later GSX-R front end with a 17" wheel. How would this change affect the handling and overall "feel" of the bike?
Thanks,
Bix

The bike will have the feel of a modern bike without doing anything to the frame
I did it on two of my bikes one a GS 1100 Katana with GSXR 1100 K components and one on a GS 1000 S with GSXR 750/1100 G/H components.
The biggest change comes from using the more modern fork on the Kat.
Beware however that most GSXR forks are too short
In the end, I used bandit phase 1 fork tubes in GSXR triple trees
Here's a picture:

[bix49]

Thanks for your replies. John, I've got a couple questions for you. Maybe it's just some forced perspective in the photo, but your rear wheel appears to be a bigger diameter than the front. Are both wheels the 17" of the GSX-R? Also, did you have any significant problems in getting everything to line up properly?

Bix

[jwhelan65]

You will need to address the rear as well, here is my build in progress..

[John Kat]

Thanks for your replies. John, I've got a couple questions for you. Maybe it's just some forced perspective in the photo, but your rear wheel appears to be a bigger diameter than the front. Are both wheels the 17" of the GSX-R? Also, did you have any significant problems in getting everything to line up properly?

Bix

No, the rear wheel is also a 17" with a 160 tire on a 4.5" rim.
Here's more info for you: http://www.thegsresources.com/_forum...=189264&page=2
And here for the front end except that the fork tubes are now from a Bandit 1200 phase 1: http://www.thegsresources.com/_forum...d.php?t=188127
Plus some considerations on fork lengths: http://www.thegsresources.com/_forum...d.php?t=186805
For the line up, I used a laser device that you can see on one of the pictures. Beware that my rear shocks allow the chain to clear with a 13 mm front offset sprocket. With std shocks you might have to use a different strategy

[kingofvenus]

The bike will have the feel of a modern bike without doing anything to the frame
I did it on two of my bikes one a GS 1100 Katana with GSXR 1100 K components and one on a GS 1000 S with GSXR 750/1100 G/H components.
The biggest change comes from using the more modern fork on the Kat.
Beware however that most GSXR forks are too short
In the end, I used bandit phase 1 fork tubes in GSXR triple trees
Here's a picture:

Very nice. If i had a Katana it would probably look a lot like your bike.

[kingofvenus]

My 750 with rf900 fork.

[John Kat]

My 750 with rf900 fork.

Very clean
What are the dimensions of the RF 900 fork ( diameter and unloaded length)?
Is it adjustable apart from spring preload?
What swingarm did you use?
Same for the exhaust?
When you see these type of bikes you wonder if Honda didn't miss their target with their neo retro bike?

[kingofvenus]

Fork is 43mm, only preload. I do not know what the length is, i would assume it is pretty close to a gsxr fork. I wouldn't want it any shorter. Arm is '93-'94 1100 gsxr with a hayabusa shock. Pipe is what they (yoshimura) sold as a "race" pipe for '83 750's, mid-pipe is shortened two inches and the mounting tab was moved forward. Pipe has been on it since i installed it in '84.

[bix49]

front end swap

Hello,
I've been pretty busy following up on the information found in these last replies. I've already learned a lot and again, my thanks for your input and experience. I just got a line on a complete front end, minus the wheel, from a '92 GSX-R. I've checked bearing size and they are the same so there's no problem there. I believe it was john kat who posted that short list of fork tube lenght, the longest (GSX-R G/K) has a length of 767mm. My '83GS11 a lenght of 787mm a difference of 20mm. Is that a large enough deviation from stock to cause a problem? Is anyone faniliar with with that fork in general? Any glaring faults or deficiencies that I should be aware of? Last question for now. I know that handle bar clamps have to installed on the top triple clamp If you want to use tubular handlebars. Has anyone done that or does anyone know how that would be done?
I've got more questions but it's getting late and I'm fading fast.
Thanks again
Bix

[John Kat]

Katman has used later GSXR forks on his bikes:

http://www.suzuki-katana.com/katana_suspension.html

The main issue with shorter forks is ground clearance in the turns.
Personally, I don't like to ride bikes that don't have 45° of static lean angle.
This means that every part that protudes laterally from the center must be equally high from the ground up.
The goods news with the shorter forks is that the caster angle decreases making the bike more nimble for the twisties
Every time you lower the front end by an inch will decrease the caster by 1°.
As our bikes start with 28° there is no problem from that standpoint
For the handlebars many people use these kits: http://www.ab-m.de/Superbike/Superbi...::63_64:5.html

[bix49]

front end swap

That's good information John, but I have a question. Shouldn't an additional 2 inches be subtracted because of the 2 inch smaller diameter front wheel? Ultimately this may not really make much of a difference to me. I am, unfortunately, getting older so I probably don't lean as far as I used to and I certainly don't lean as far as I thought I used to. It is however good stuff to know. Thanks, Bix

[John Kat]

That's good information John, but I have a question. Shouldn't an additional 2 inches be subtracted because of the 2 inch smaller diameter front wheel? Ultimately this may not really make much of a difference to me. I am, unfortunately, getting older so I probably don't lean as far as I used to and I certainly don't lean as far as I thought I used to. It is however good stuff to know. Thanks, Bix

You are right Bix, but typically our old GS's had, I believe, more static sag than the current suspensions so it's maybe not as much as 2 inches?
Then don't forget that the rear will also go down if you install a 17" low profile tire.

[bix49]

front end swap

Yea, wheels and tires are on my list but this project or a least the purchasing of parts, will have to be done in stages. Maybe next year at this time I will have been able to buy all the necessary parts and I can begin the swap. You know I've also been intrigued by the idea of a monoshocked GS11 ever since I saw a small picture of one in a 1995 issue of "Streetfighter" magazine. Seeing what Kingsofvenus did with his 750ES excites me all over again. What a sanitary,professional job. I might never get to that mod, but you never know. Thanks for you input, John. I'm sure there are more questions on the was. Thanks, Bix