80 GS1100E mods

[Anonymous]

HI - I'm new to this forum - great one BTW! I'm going to rebuild and update my 80 GS1100E for my son who is in the Marines.

What I would like to do is replace the complete front fork assembly (wheels, brakes, forks, bars, controls, etc) with a more modern unit from a GSXR. I am also considering replacing the rear swingarm assembly with a monoshock unit from another GSXR. I has spent some time looking at some conversions that are interesting but don't have any detailed pictures or information. If anyone has any info that would help me I would really appreciate it.

I currently own a Kawasaki 1200 (Lawson replica) and Honda XR650R (way too much fun in the dirt). I have rebuilt several cars from ground up restos including a 70 VW for my wife so I have the tools and mechanical ability to do everything that needs to be done. I just don't want to flounder around on this. I would like to get a good understanding of what needs to be done before I start.

Any and all help would be greatly appreciated. If the information is too detailed for the form please email me at tambra9158@hotmail.com (wifes acct - too lazy to make my own!)

Thanks,

Steve

[Billy Ricks]

The front end is a snap as long as you use a complete front end; wheel, rotors, caliper, speedo drive, etc. Just stay away from the '88 GSX-R750. It was the shortest ever used. The 1100 front ends are generally about an inch longer. I didn't have room for clip-ons between the tank and fork so I drilled and tapped the top clamp to accept a set of bar mounts so I could use and standard style bar. I also installed GSX-R guages to have correct speedo readings.

You can probably fit a 4.5" wheel in your stock swingarm if you don't want to go the whole switch. Just knock out the GSX-R bearings from the wheel and sprocket carrier and install your GS bearings. You will have to use Katana 600 spacers and caliper hanger. You also have to use the bearing spacer from inside the wheel hub from your GS and add a piece of steel tubing to get the same total length as the GS piece. There is a spacer inside the sprocket carrier that needs to be switched out for the Katana piece. The brake torque arm has to be moved to the bottom of the swingarm.

If you want to do swingarm and all it is quite a bit of work. First you have to remove your stock pegs and cut off the frame brackets the pegs mount on. Then weld on steel plates near the outer edge of the frame to mount GSX-R rearsets. Then you have to fly cut the inside of the frame where the swingarm pivot shaft goes through. Those things have to be done to fit the swingarm in the frame. I got around using the GSX-R pivot shaft by removing the bushings that fit inside the swingarm bearings from the GSX-R piece and cutting down my GS bushings lengthwise to fit the GSX-R swingarm. That allows me to use the GS pivot shaft. The GSX-R shifter linkage caused me to end up with an upside down shift pattern since there is not enough room between the shifter shaft and the countershaft sprocket cover to flip the linkage over.

By the way, I did these mods to an '85 GS700. Sorry, no pictures yet.

[Anonymous]

Billy:

Your speedo didn't work correctly after the front wheel conversion? I was under the impression that all Japanese speedos are switchable as long as the speedo drive is matched to the wheel. I saw this in a parts book.

Steve

[Anonymous]

Thanks for the info on which fork assemblies to use. If I understand this correctly - I can use any front fork assemblies? Does this include the newer inverted forks? I guess if the dimensions on the steering head are the same then it should bolt right up. There would be some modifications to the steering stops to keep the bars out of the tank I would guess.

I started tearing into this bike yesterday. I plan on taking a lot of pictures and documenting my work. (I made the mistake of only taking a few pics of the VW resto). I'm not sure where to post the pics as I do not want to take up any more space in this forum. Maybe there is a way of creating a public folder on my computer and just posting the links. I'll look into this as I progress and get more pics - only 3 now.

I will also be rebuilding this motor as it deveped an oil leak just before I quit riding it over 10 years ago.

I appears as if the rear assembly is going to be the trick.

I am checking out ebay now for fork assemblies. Most are only the forks without the rest of the goodies. My best bet may be to contact some salvage yards for the parts I need.

This little project may take some months to be completed. It's a bad time of the year to scrape up extra cash (Christmas you know) and I just broke my finger dirt bike riding. It's a little tender using wrenches.

Thanks again,

Steve

[gtsg01]

Front Forks

Try searching for "Front End" on eBay. Some other search parameters are,
Triple Tree
Triple
Triples
Tree
Trees
Clamp
Clamps

The people who list things on eBay are not always bike people, so they just call things whatever they want. I hope this helps.

[Billy Ricks]

Billy:

Your speedo didn't work correctly after the front wheel conversion? I was under the impression that all Japanese speedos are switchable as long as the speedo drive is matched to the wheel. I saw this in a parts book

Steve,
The old wheel was a small 16" and the GSX-R wheel is a fat 17" so the speedo was off by about 10%. The tach burned out due to a shorted battery so it gave me an excuse to switch to GSX-R guages, something I wanted to do anyway.

Thanks for the info on which fork assemblies to use. If I understand this correctly - I can use any front fork assemblies? Does this include the newer inverted forks?

You can use an inverted GSX-R fork as well. Guys are bolting late model GSX-R front ends onto early GSX-Rs so it stands to reason they'll bolt onto a GS too. If you get your hands on a copy of Cycle News there is a classified section in it where racers get rid of stock take-offs when they upgrade parts. It's not uncommon to be able to find everything you would need there. The fork and wheel will be the most expensive even on Ebay. Calipers and rotors are usually pretty reasonable. You should be able to use your stock master cylinder if it is still good. I'm using mine with braided steel lines and my lever only goes back maybe 3/4 of an inch. I would think you could get the complete front end for about $400 even getting a piece here and there.

You can either drill and tap the lower clamp and use bolts that hit the fork stops on the frame to keep the bars out of the tank or do what I did. I bought some of those rubber blocks you insert into auto coil springs to stiffen them up. I cut out some thick L-shaped pads then used weatherstrip adhesive and glued them to the frame where the lower clamp hits them. I have to replace them once in a while but it's no big deal. They are black and are pretty well out of sight so they are not at all ugly.

[Anonymous]

I talked to someone at a salvage yard who informed me that it would be easier getting the new GSX-R1000 front forks than the 1100's. Anyone know if they have the same dimensions for the steering head?

I also have a lead on a set of forks off of a GSX-R750. Any negatives on using these? I imagine I could set them up with heavier springs if needed.

I know I'm asking a lot of questions about this, please bear with me.

Steve

[Billy Ricks]

750 forks should work fine. Most of them have preload adjusters. The stock springs may work fine. If not you can always replace them with heavier springs.

[HiSPL]

There's a lot of info on this Netherlander's website about oil-cooled GSX-R's that can be used for our purposes click on the 7/11 boulevard tab at the top of the page. Remember also that when they say GSX**** they are talking about the same bike as our 80-85 16 valve GS's. Good luck, I would like to see how this turns out.

http://www.robbynitroz.nl/common/frameset.htm

[Anonymous]

Back again. I purchased a set of '93 GSXR1100 front forks and triple trees for US $ 195 on ebay. I'll let you all know if they fit when I get them. I can see from the pictures that they have tapered roller bearings, so that looks promising. They are also inverted!

I talked to some fellows at a motorcycle salvage yard who do a bit of the type of work that I'm attempting here. They informed me that not all GSXR forks have taper bearings. Some come with caged bearings - those forks would then not be a straight swap. While it's possible to make anything fit, I didn't want to make any more work than necessary. So when I saw these with tapered bearings I had to bid.

I think that the easiest front wheel to use with these forks would be off of a GSXR with inverted forks. I'm not sure if the wheel from a non-inverted unit will bolt right up. Does anyone have an answer? It would be nice if I could choose from 600, 750, 1000, or, 1100.

Steve

[Billy Ricks]

Non-inverted wheels should work since the first inverted forks still had the same 4 pot calipers bolted to them. Just don't go with the '86 or '87 wheels, they were 18" wheels. Go with a 17" wheel, that's what the best rubber comes in.

[Anonymous]

OK, I got the forks and triple trees a couple of days ago. They bolt right up! The only part I'm using off the old tree's are the top dust cap - the one from the gsxr was too big. I'm pretty happy with the ease of instalation - Thank you Suzuki!

I split the cases yesterday and the bottom end looks very nice. The oil leak that I had when I parked this beast looks to be the lower cylinder gastket. As a matter of fact, all of the gaskets were brittle. I'm surprised it held oil at all. Now to get it cleaned up and possibly painted flat black.

[Anonymous]

For those that are interested.

I mocked up the front and rear suspensions a bit today. The swingarm that I purchased through ebay didn't fit so I'll have to get some more measurements and check around a bit. I like the looks of it so far. It's real dirty sill - I'll clean it up later after I get a good fit - then send it away for powder coating.

It's sitting on a home made stand and the front wheel is touching. The back wheel is being held in place with the dirt bike stand. The rear is a 180 and it looks as if there is enough chain clearance by using the lower cases as a template. I'm looking for a stance similar to this.

http://groups.msn.com/SuzukiGSGarage/yoshimurags1000article.msnw?action=ShowPhoto&PhotoID=778

[Anonymous]

Ok - latest update. I mounted the 94 banana swingarm today to check for fit. I was able to get the pivot area of the swingarm into the proper position by simply removing the pivot dust covers and one of the bushings. It was tight but I was then able to look to see where I can mount the link pivot (not sure if thats the correct name) for the monoshock. It turns out that the mounts for the centerstand are almost perfect for this application. I had to remove from the frame - the post mount for the brake return spring and the mount for the brake sensor so that the swingarm had clearance to move. I also cut the centerstand mounts such that there is only one (not 2) eyes per side.

I'm sorry a lack of pics, but the cameras batteries went dead. Tomorrow I'll take some. I will clean up the areas with a grinder that I cut today also. I used a cuttoff wheel, a chisel, and BFH to do the dirty work.

I'm not sure if I'm going to use the banana swingarm yet. If I do, I will have to go with the monoshock. The swingarm is about 2" longer than stock, but it looks pretty good mounted up.

If I use this swingarm I am leaning towards cutting the pivot area back on the swingarm itself rather than make the frame area larger. This means taking it to a machine shop. Oh well.

One last note today - the rear brakes are going to take a bit of thought. There is very little clearance for the stock unit. Even if I could mount it, I already cut some of the mounts off the frame for it to work properly. I have a gsxr unit and will see what I can come up with. Suggestions welcome!

[Anonymous]

Here are some pics for you to get an idea of what I was talking about in the previous post. I still haven't cleaned up the cuts yet so they look pretty bad.

http://groups.msn.com/SuzukiGSGarage/yoshimurags1000article.msnw?action=ShowPhoto&PhotoID=814

This pic shows how the centerstand bracket has been cut away. Only the inside mounts are kept. The hook for the spring has been hacked away also.

http://groups.msn.com/SuzukiGSGarage/yoshimurags1000article.msnw?action=ShowPhoto&PhotoID=815

Another view - this time showing the right frame better. The brackets for the brake pedal indicator and return spring are gone.

http://groups.msn.com/SuzukiGSGarage/yoshimurags1000article.msnw?action=ShowPhoto&PhotoID=812

Showing the swingarm mounted with the linkage connected to the modified centersand mounts. I'm holding the linkage in the fully exteded position. Just a mock up - the bolts used are not the correct length or diameter. I'll probably have this torn apart 2 dozen more times fitting parts. One other note - I may have to position the mounts so the that bolt holing the linkage is to the rear a bit more. Also some bracing way need to be added. TBD later.

http://groups.msn.com/SuzukiGSGarage/yoshimurags1000article.msnw?action=ShowPhoto&PhotoID=812

View of the swingarm a step back. Notice that the swingarm is now in the fully compressed state.

http://groups.msn.com/SuzukiGSGarage/yoshimurags1000article.msnw?action=ShowPhoto&PhotoID=806

Fully extended with the rear wheel in rough position. The photo is labled incorrectly.

http://groups.msn.com/SuzukiGSGarage/yoshimurags1000article.msnw?action=ShowPhoto&PhotoID=807

Another mislabled photo. Fully compressed this time.

http://groups.msn.com/SuzukiGSGarage/yoshimurags1000article.msnw?action=ShowPhoto&PhotoID=808

http://groups.msn.com/SuzukiGSGarage/yoshimurags1000article.msnw?action=ShowPhoto&PhotoID=808

The last two photos show the position that I'm shooting for. The rear shock will have some preload and compressed a bit.