81 GS1100E... which swingarm do i have??

[RocketScientist]

So I have an 81 GS1100E that i bought earlier this year. A previous owner has done some work converting it to a "cafe" style bike, so its not stock, but so far most of the mods have been appearance, and the suspension/drivetrain/chassis all seems pretty much stock from what I can tell. But this bike has been my entry into the GS world, so not like I'm an expert. My next project is to replace rear shocks, new sprockets/chain (and a conversion to 530 chain), and while I've got it apart was going to replace the wheel bearings, and contemplating replacing (or at least inspecting/greasing) the swingarm bearings. So i'm on the parts fiche looking at what bearings, seals etc would be needed, how its all put together and such. And I notice the swingarm in the drawing looks nothing like mine, and googling of the lsited part number looks nothing like mine. The parts fiche shows a tubular (steel?) swingarm, but my bike has an aluminum swingarm of a rectangular cross-section. And this matches photos of stock/new '81 GS1100Es, so I'm guessing its correct/original. But digging through the parts fiche, I need to go to an '82 1100E to find a swingarm that looks like mine.

So, bottom line... why does the parts fiche show my bike having a different swingarm than what (seemingly) was actually installed at the factory? Whats the story there? I think this is mainly an academic question, all the parts (bearings, spacers, seals, etc) are identical between the two years/styles. The only difference is the '82 (square aluminum) swingarm fiche doesn't show a washer used under the head of the swingarm bolt, just under the net (and the '81/tube swingarm shows a washer under both).

[1978GS750E]

The '81 GS1100E sitting in my garage has an aluminum swingarm. Pretty sure that is what was stock on that bike. Same swingarm that was on the '83 GS1100E I used to have, I believe. Parts drawings are not real exact and some get re-used from one model year to the next for some reason???

[Big T]

Not sure what parts fiche you're looking at, so I checked my local dealer.
It shows 2 rectangular aluminum swingarms

[Rob S.]

Cycle World called the '81 a "built-up box section aluminum" swing arm and I'm rather certain it is identical for '81, '82 and '83. Probably for 1980 as well.

[rphillips]

Yep, all 16 valve 1100's had alum., even the L's". Quickest way to tell difference, at a glance, in the Gs750 16 V & a GS1100 16V, in those yrs. as all body parts were identical, was look at the swingarm, all the 750's had the steel.

[RocketScientist]

I checked the parts fiches at Babbits/Suzuki Parts House, Partzilla, and CMSNL. All showed the '81 having a tubular swingarm, with a diff part number from the rect. aluminum they show for the 82.

https://www.partzilla.com/catalog/suzuki/motorcycle/1981/gs1100e/rear-swinging-arm

https://www.cmsnl.com/suzuki-gs1100e-1981-x-usa-e03_model34166/partslist/BLCK0042.html#.YalgM9DMJPY

https://www.suzukipartshouse.com/oemparts/a/suz/50d403bff8700230d8b4eb9b/rear-swinging-arm

So I'm assuming mine has the one shown here (for the 82):

https://www.suzukipartshouse.com/oemparts/a/suz/50d403f1f8700230d8b4ebeb/rear-swinging-arm

Weird.

[Rob S.]

I checked the parts fiches at Babbits/Suzuki Parts House, Partzilla, and CMSNL. All showed the '81 having a tubular swingarm, with a diff part number from the rect. aluminum they show for the 82.

I really couldn't tell from the fiche foto that they were depicting a tubular swing for the '81. But if so, not so weird, just a mistake.

[phydeauxmutt]

Are you SURE you have an '81? I ask that because mistakes are not uncommon when a title is issued. Some states will call a bike an '81 if it's sold in '81, regardless of when it was actually built. Can't go by the build date, either, because production of the '81 bikes started as early as August of 1980. Suzuki is also the master of "parts bin engineering", and also making up differences on the assembly lines. Maybe they ran out of aluminum swingers that day and had to borrow some from the 750 line?

And, unless you are the original (and ONLY) owner, who knows what somebody has done.

[zuluwiz]

As I recall: Every 16-valve 1100 had the built-up square section aluminum swingarm. This was a New Idea from Suzuki. No manufacturer had used a swingarm like that previously. The 16-valve 750s (and all smaller engines) used the round-tube steel swingarms.

[Grimly]

It was also a reaction from Zuk to make the back end more like the track bikes where riders had been fitting beefy braced alloy rectangular tube swingarms for years.

[storm 64]

I know the KZ guys have been adapting the GS swing arm to their motorcycles for years. Pushing the price up to $200+... I'll hang on to my stash a little bit longer. Unless someone really wants one... 👍

[TeamDar]

As I recall: Every 16-valve 1100 had the built-up square section aluminum swingarm. This was a New Idea from Suzuki. No manufacturer had used a swingarm like that previously. The 16-valve 750s (and all smaller engines) used the round-tube steel swingarms.

The single year 1980 GS1100L was a chain drive 16 valve and had a round tubular steel swing arm. Dar

[rphillips]

TeamDar, I sure thought I remembered the "80" GS1100LT had the alum. swingarm, I didn't trust your opinion. I looked at the photo gallery, on this site, & it sure looks like you are correct. No perfect pictures but they sure do look like they did have the older style steel tube swingarm. Thanks for bringing this out.

[Rob S.]

The single year 1980 GS1100L was a chain drive 16 valve and had a round tubular steel swing arm. Dar

These are the kind of details I love. I could sit and listen to details of every single option available on a '60's Corvette over and over.

TeamDar, I sure thought I remembered the "80" GS1100LT had the alum. swingarm, I didn't trust your opinion. I looked at the photo gallery, on this site, & it sure looks like you are correct. No perfect pictures but they sure do look like they did have the older style steel tube swingarm. Thanks for bringing this out.

Member Peppermint Patty would be a good source for info about that model. Though I know she's not riding it anymore, I think she might still own it.

[Nessism]

Short answer: the parts fishe image is wrong.