GS1100 Swinger on a 1000 V Stock Steel

[salty_monk]

Has anyone done the 1100 Swinger on the 1000 Mod & ridden it back to back?

I have a stock steel on mine but I've had an Alloy 1100 one on a shelf for an age....

Wondering if there is any huge benefit if you stick with stock wheels etc...

Only one I know of for sure is a 7lb (so I've been told) weight drop which being partially unsprung weight should have a positive effect on the suspension...

Vertically I can see that the Alloy one should be stiffer but horizontally I would think the steel one could have the edge (diameter of the tube is thicker than the Alloy one) however I am not sure about performance characteristics of rectangular tube over round.
Bracing on both units is very similar.

Dan

[TheCafeKid]

If you look at the alloy one, it's not only boxed, but arched across the pivot, there's more meat up there too... I did one on my cafe 750, and the lateral stiffness felt substantially better... Just my simple seat of the pants findings..

[hampshirehog]

Big improvement Dan - you'll notice it the first time you get on a long sweeping bend with a few bumps in it. That, decent new springs front and back, fork brace and a steering damper will revolutionise the way the bike handles.

[Tarbash 27]

If you look at the alloy one, it's not only boxed, but arched across the pivot, there's more meat up there too... I did one on my cafe 750, and the lateral stiffness felt substantially better... Just my simple seat of the pants findings..

A 750 swingarm is much smaller than a 1000 swingarm. Smaller diameter tube. So you would probably notice more of a difference in between a 750 and 1100 than a 1000 and 1100. Plus you get a bit more wheelbase when puting an 1100 swingarm on a 750.

[KiwiGS]

Reducing the curb weight won't hurt either...........

[GregT]

From a theoretical point of view the rectangular tube arm has the material disposed almost exactly according to the load
From a practical POV it works...

Along with the arm the best thing to finish the job is the 18in rear wheel too - the handling is better with the lower sidewall of the 18 vs the tall 17

[salty_monk]

Thanks... It's really the last bit left on my skunk, that & maybe cartridge emulators.

I have progressive front & rear, fork brace etc. Never thought of fitting a damper - so far never felt like I've needed one on the 1000 or the 750.

Also toying with the idea of cutting some of the progressive end off the progressive springs & running a little less preload in order to help with brake dive - thoughts?

I have had the 1100 swinger for years & am now coming to the end of the life of my tyres & sprocket & chain so this winter I may change the whole thing. Also moving to an 83 wheelset too so I can go tubeless (better for a middle of nowhere repair plus again less unsprung weight from losing the tube - not sure if that wheel weighs less too but I intend to weight them before I fit them).

[GS750]

How did you go with this conversion Salty Monk?

I just searched and found this thread because I just fell upon an alloy swingarm from an Aussie GSX1100 ( I think anyway) and its an 82/83 model/


I have compared it to my 1977 GS750 swing arm and it fits in, the only issues that I can see are the following:

1. The swingarm pivot bolt on my 77 -750 is 14mm, the swingarm bolt on the alloy one is 16mm
   
2. The rear axle mounting on the alloy swingarm is 35mm further back (longer)
   
3. Rear shock mounts are 30mm further back on the alloy swingarm

I see 2 choices, machine up some new 14mm spacers, what material though? stainless? OR machine/drill the holes out on my frame??

I have access to the proper gear to go either way, keep the 14mm or convert my swingarm mounts to 16mm.

??Thoughts??

[gearhead13]

I just drilled out the frame for the bigger pivot, quite easy with a decent drill.

[GS750]

I just drilled out the frame for the bigger pivot, quite easy with a decent drill.

Thanks Gearhead!
Thats what I thought would be the better way (less machine time making the spacers lol)

I noticed on my parts bike frame, that there is a large hunk of solid metal pad on the frame mount so taking 1mm more wouldnt really be an issue

Did you drill the frame out by hand or jig it on a bench drillpress / magnetic drill??

Have you noticed anything different handling wise?? Im guessing the longer wheelbase would make it more stable.

[gearhead13]

Thanks Gearhead!
Thats what I thought would be the better way (less machine time making the spacers lol)

I noticed on my parts bike frame, that there is a large hunk of solid metal pad on the frame mount so taking 1mm more wouldnt really be an issue

Did you drill the frame out by hand or jig it on a bench drillpress / magnetic drill??

Have you noticed anything different handling wise?? Im guessing the longer wheelbase would make it more stable.

There is plenty of meat there for the extra size. I found that a 5/8" drill bit is about the right size. I just used a hand drill and went very carefully. After the holes are drilled, check for stratighness with the pivot bolt and adjust the angle as necessary. Before the alum swinger, I could feel the flex of the arm under acceleration, like it was twisting. Especially with the hopped up 1100 stuffed in there
Much more stable and predictable all around after the swap.

[TheCafeKid]

I drilled my frame out as well when I did it. Not tough. Go slow, use some oil. I ran a dowel rod through from one side to the other to act as a guide. If you drill it crooked on one side by a 1/8 inch it will translate to much more by the time it gets to the other side of the frame. Let the bit do the work and be patient though and you should have no problem.

[GS750]

Awesome! Thats the plan to follow then!

I have access to a magnetic industrial lineboring drill press which I can use to make sure the holes are drilled on the same line as the existing holes Plan sorted! Thanks for the extra info, Im really looking forward to the upgraded rear end!!

[oldgrumpy]

old swing arm v,s alloy,,,,,

i was lucky enough to get a gsx1100 alloy swing arm in nice condition,,, and i have noticed that there is less flexing in the back end,,, ,,,,i,ve got progressive springs from usa in the front,,, great improvements easily done .. regards oldgrumpy

[ozgs]

Can't remember where I read it, but I have read the Mick Hone commented when he was building Robbie Phillis's Forgotten Era GSX1100 that the alloy swingarm was a real problem with flexing. He said that the steel swinger was actually stiffer. The majority of GSX's that you see racing here had tubular bracing added to them.