1980 GSX1100 front end swap

[revrdmark]

So I recently bought a 1980 Suzuki GSX 1100 as a café build. The bike was/is a running bike but the previous owner did some questionable “repairs" to the bike,

The front forks are the Pneumatically adjustable kind and they are over 40 years old not to mention the previous owner said that he replaced the springs with progressive springs. His questionable mechanical work makes me nervous that he may have damaged the air system in them or just done them incorrectly

I’d like to replace the front end. After doing some research here I see that the early GSXR forks look like they will mostly bolt in with some minor modifications. Finding a complete front end would be great but I think I may have to piece together the forks, triple tree, axle, wheel, brake rotor and calipers but hoping I’ll get lucky and find a compete front end that fits without a major modification.

My question is: are there other bikes that you all may know of that would fit the correct length of the head stock (with new bearings) such as early Katanas or Sv 650/1000? Thanks for any suggestions or info

I'll be starting a build thread in a couple days

[slayer61]

1). Welcome.
2). There's lots of info on this site about fork swaps.
3). Use the search function

mine

https://www.thegsresources.com/_forum/showthread.php?206922-89-GSXR-front-end-with-18-quot-wheel&highlight=astralite

search function results = https://www.thegsresources.com/_foru...archid=3619209

[Tom R]

Short of breaking off the schrader valve, I don’t know how anyone can bugger up the air system. It’s not really a system, just additional pressure.

[Rijko]

So I recently bought a 1980 Suzuki GSX 1100 as a café build. The bike was/is a running bike but the previous owner did some questionable “repairs" to the bike,

The front forks are the Pneumatically adjustable kind and they are over 40 years old not to mention the previous owner said that he replaced the springs with progressive springs. His questionable mechanical work makes me nervous that he may have damaged the air system in them or just done them incorrectly

I’d like to replace the front end. After doing some research here I see that the early GSXR forks look like they will mostly bolt in with some minor modifications. Finding a complete front end would be great but I think I may have to piece together the forks, triple tree, axle, wheel, brake rotor and calipers but hoping I’ll get lucky and find a compete front end that fits without a major modification.

My question is: are there other bikes that you all may know of that would fit the correct length of the head stock (with new bearings) such as early Katanas or Sv 650/1000? Thanks for any suggestions or info

I'll be starting a build thread in a couple days

Just curious, do you really want to modify the bike ?
Bad enough to go through the hassle of finding parts, and the cost and labour that comes with that ?

Or just apprehensive about checking your front fork ... (if so, the guys on this forum can guide you)
Remember you will need to check and possibly repair the 'new' wheel bearings, tires, brakes and pads, etc etc on those, too.

[wyly]

Just curious, do you really want to modify the bike ?
Bad enough to go through the hassle of finding parts, and the cost and labour that comes with that ?

Or just apprehensive about checking your front fork ... (if so, the guys on this forum can guide you)
Remember you will need to check and possibly repair the 'new' wheel bearings, tires, brakes and pads, etc etc on those, too.

yeah the price rises very quickly when doing swaps, there always seems to be one more item to change out..until there's another that needs replacing as well.

[revrdmark]

Short of breaking off the schrader valve, I don’t know how anyone can bugger up the air system. It’s not really a system, just additional pressure.

This is the first time i've worked with these type of forks. Its good to know that its just a simple pressure system with not too much to damage or reinstall incorrectly! Thanks

Just curious, do you really want to modify the bike ?
Bad enough to go through the hassle of finding parts, and the cost and labour that comes with that ?

Or just apprehensive about checking your front fork ... (if so, the guys on this forum can guide you)
Remember you will need to check and possibly repair the 'new' wheel bearings, tires, brakes and pads, etc etc on those, too.

Ive done seals and/or replaces springs to set up the suspension on almost every bike I've owned from Suzuki SV's to Buell's to Ducati's to KTM's so Im not too worried about cracking the forks open and rutting around in them. I was assuming I will need to tear into them since the preload screws are drastically different on each of the forks which makes me suspect of installation of the progressive springs and reassembly that the previous owner did. (If I keep the same front end i will be checking the insides regardless) The other reason for looking into more 'modern' front suspension is the basic handling quality. Im not an 18 year old 120 lb kid anymore. Id prefer a bit more stiffness and heft to them when i lean my fat old man butt into a turn at speed :-)

I was hoping to find a bike that someone is parting out or a salvage title bike that wasn't destroyed in a front end crash, so that i wouldn't have to source all the individual components. It would be nice to do a swap of a functioning front end... Just looking for information on what bikes would be easiest to swap, although I'm sure you can make anything work with enough time, $ and creativity

[Rijko]

I think if you upgrade to Sonic springs you will like the way it handles.
Several members here have done so inc me and i like the handling.
Their spring rate calculator is here :

http://sonicsprings.com/catalog/calculate_spring_rate.php

I later added a MikeXS damper valve (https://www.mikesxs.net/yamaha-xs650...170-00-00.html) (these are 35mm dia so i had bushings made to fit my 37mm forks) and a fork brace, but that did not improve much.

I looked at other forks like GSXR stuff but the smaller wheel and shorter forks took away too much ground clearance.

If you want more improvement and better brakes you could consider a front end from a Honda VTR1000f Superhawk like this guy did :
(i think all that was needed was an All Balls conversion kit)

There are others here with more experience with these fork swaps,
but here's a list you could use for comparison :

https://www.allballsracing.com/forkconversion

[wyly]

The best OEM fork upgrade I did was converting to Race-tech cartridge emulators and springs, if you have a drill press it's not difficult to install. The conversion retains the oem look while significantly improving suspension.

https://racetech.com/page/title/Emulators

[revrdmark]

Found a 2005 GSX750 parts bike for sale very cheap with straight forks. With the All-balls conversion kit and the fork rebuild kit i am still way ahead of the game for the upgrade. I'll post some pics and updates as the swap goes forward.

[revrdmark]

So it’s been ages since I’ve been able to do any work on the GSX. Life and winter and unheated garage stopped me from much work. But started spending some time with it again. The Katana forks were a bust. The smaller front wheel made the geometry of the bike too far out whack so I parted out the donor bike and made my money back. I’ll go through the stock forks and get them in good shape for now and just keep my eyes, open for a suitable donor with correct wheel and fork dimensions.