GS550E Brake Swap tutorial with Photos

[8trackmind]

First off, if you do this, it's at you're own risk.
If you don't have the skills, the tools or the right parts...stop right here.

The casualty of this swap is my very own 1980 GS550ET. This should work on a '78 or '79 as well.
While I'm sure someone else has done this mod, I have no pictures for proof. If anyone else has any tips, tricks or pics, by all means post them.
I want to put this to bed once and for all.:-D

The victim...

That plastic cover just pops off.

 

[8trackmind]

Step 1. Disconect battery.
Step 2. Drain coolant.
(that was for all you Chilton manual owners)

Let's start with the, specs. The forks on my bike are 35mm dia.
From the center of the axle to the top of the fork tube is 30 1/2" long.
The forks I will be using for the swap are from a 1981 GS650E. They are 35mm and 30 1/2 long also. So far so good.
The calipers I'm going to use are from a '79 GS850gl. They are single piston tokico's.
EDIT: I ended up using calipers from a 81 gs650e.
The rotors are from the gs 850 as well. (you can use the rotors that came on any of the dual disk bikes 78 to 83)
The master cyl will be from a '97 Katana.

I am not swapping the triple tree...It's the stock 550 unit.
I'm also using the same wheel. All you have to do is pop the
plastic cover off the right side. It's already drilled and threded
for double disk.

Go ahead and remove the front wheel, fender, string up you're caliper and remove the speedo drive. blah blah blah.
Loosen you're 14mm bolts on the triple clamps.
In some cases. you may have to take the bars off.

Getting there.

 

[8trackmind]

Go ahead and slide the 650 forks in. (you did replace the seals and put the proper amount of fork oil in, right?)

This is the first of two minor problems you will encounter.
The spacer on the right side (throttle side) is too wide...

Be sure to have a hatchet around the garage...you never know when
it'll come in handy.

I cut one out of 1/2 pvc to get the correct width. (it goes without saying that you can't ride it with the pvc in there) but then again, McDonalds coffee is hot and some folks don't know that either.

Here is the spacer before I started grinding on it. I'm not going to tell you how much I cut it because it needs to fit YOUR bike. (about 2 mm)
Take your time. Be sure to get it right or you may die! (Not really but do it right anyway.)
I use the same hi-tech tool I always use...drill with a cut off wheel.

 

[8trackmind]

Here's where we're at with wheel back on.

 

[Roadwarrior]

I've wanted to do that mod to my 78' since the first day I rode it. It single front disk can barely cut it when I ride solo, but 2 up its lacking.

Do you know of any dual disk spoke rims that will work? I think the XS650's had dual disk spoke front rims, but I have no Idea if it will fit

 

[8trackmind]

For now, I'm putting the original (single) caliper back on the bike 'till I can finish cutting on the forks.

Stay tuned for part II​

 

[8trackmind]

I've wanted to do that mod to my 78' since the first day I rode it. It single front disk can barely cut it when I ride solo, but 2 up its lacking.

Do you know of any dual disk spoke rims that will work? I think the XS650's had dual disk spoke front rims, but I have no Idea if it will fit

The right side of the hub may already be drilled for the second disk on you're rims. Have you popped the cover off the right to check! Does it have a cover? I know nothing about the spoke rim models. Edit: The spoke rims are drilled for two rotors.

 

[8trackmind]

Break swap part II​

Revenge of the calipers!
Here is the '90 something 750 Katana Master cylinder I plan on using.

Btw, the 4 piston tokico calipers that came with it are a no go.
1. their too wide. (hits the rim)
2. the brackets aren't even close.
3. the mounting bolts are smaller as well.
(they are now for sale if anyone is interested)

Left side (shifter side) caliper bolts right up with no problems.
Right side will not fit. Caliper bracket is a a bit too wide.
(not really, the triple tree is narrower because it's not for double disks)
I will be removing a bit of metal from the boss's on the forks that the calipers attach to and maybe a bit from the caliper bracket as well.
I'm guessing 2 or 3 MM.
(EDIT)
If you are using the later style calipers with the square pads, you may have to remove even less from the mounting boss on the forks.

Time to go to work on the fork leg with this hi-tech tool. (cut off wheel on a drill)

​

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[AOD]

Oooh!

I planned on doing this to my 550 if I kept it, I just didn't like the feel of the brakes, even with stainless lines and new pads, though they did help. I like that you went with the black fork bottoms, that will look really cool when finished!

~Adam

 

[8trackmind]

Oooh!

I planned on doing this to my 550 if I kept it, I just didn't like the feel of the brakes, even with stainless lines and new pads, though they did help. I like that you went with the black fork bottoms, that will look really cool when finished!

~Adam

Thanks.
I agree the breaks are crap. Even worse two up. That's really the only thing about the bike I can't stand. I love it otherwise.

Right now I'm just fitting all the peices together, the calipers are going to get rebuilt and painted as will the forks. (black of course)
The rotors need to be re-surfaced too.

I'm not sure if My Katana break lines will work or not. We'll see.

Best Regards, Jeff

 

[triffecpa]

I've wanted to do that mod to my 78' since the first day I rode it. It single front disk can barely cut it when I ride solo, but 2 up its lacking.

Do you know of any dual disk spoke rims that will work? I think the XS650's had dual disk spoke front rims, but I have no Idea if it will fit

I used the front spoked hub off a GS550 when I did 18" spoked rims on my GS1000 vintage race bike. It was tapped for the right side disk, but there were some allen bolts threaded into the holes. Had to remove those (they were sunk about 1/4" below the surface) but then it wasn't a problem to bolt the second disk up.

TR

 

[8trackmind]

Two or three MM is all you need to remove.
After you get them roughed out, get a file and make everything flat.
Make sure everything fits like it should.

Once that is done, start putting everything back together. Be sure to use
a new cotter pin too. (you cheapskate)

It should look like this...
Make sure that everything is tight before you hop on it
and crash.

Forgot the brake light switch.
Cut the old one off, crimp on a couple of terminals and plug it up. Wire color does not matter. The switch only completes the circuit.

All that's left now is to bleed the brakes.

Best Regards, Jeff

 

[Roadwarrior]

I used the front spoked hub off a GS550 when I did 18" spoked rims on my GS1000 vintage race bike. It was tapped for the right side disk, but there were some allen bolts threaded into the holes. Had to remove those (they were sunk about 1/4" below the surface) but then it wasn't a problem to bolt the second disk up.

TR

What brake rotors did you use? 77-79 GS 850-1000?

 

[triffecpa]

What brake rotors did you use? 77-79 GS 850-1000?

Yeah, I reused the ones from my '78 GS1000 mag wheel.

 

[8trackmind]

Shake down report:
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I have not finished re-building My calipers (I may use a different type) but...it was 55 out today so I had to ride it! 8-[
I used the Katana Master cyl and One caliper.

If you decide you don't want to go to the trouble of doing this fork swap mod. Do yourself a favor, get a master cylinder off of a late model anything! While not exactly "sportbike" brakes by any means, the master cylinder alone made the single disk caliper feel much stronger.

The first two stops I made had me worried. There was a strange hissing sound coming from the rear. You guessed It...the rear tire was locking up because the front brake was finally doing it's job!

I can't wait 'till I get two on there. \\/

 

[AOD]

I agree the breaks are crap. Even worse two up.

Yeah, that was the worst part about my 550 too, especially two up. Since I ride 50% of the time two up, the 1100 was a good move.

If you decide you don't want to go to the trouble of doing this fork swap mod. Do yourself a favor, get a master cylinder off of a late model anything! While not exactly "sportbike" brakes by any means, the master cylinder alone made the single disk caliper feel much stronger.

I thought about this too...since the 26 year old master cylinder just can't be functioning as good as it used to. The seals go bad, parts wear, etc. The only problem with late model stuff is they do not have a mirror install tapped bung, so you'd have to use bar end mirrors or find another way to attach mirrors.

You guessed It...the rear tire was locking up because the front brake was finally doing it's job!

Take 'er easy! 8O

And fix your throttle grip, it's not all the way up on the throttle thing! Wire brush the rust off the new brake lever.

~Adam

 

[8trackmind]

The grips are all the way on. They are just shorter than what came on there. It will get new ones someday.

The mirror problem...no problem at all. '80 and up mount on the clamp, not the master.

As far as the general state of dirt, rust and crap.
I still have to pull everything back apart to paint the fork legs, the master cyl and the calipers.
I went ahead and put it all together so:

1. I could test it.
2. So I could get all the pictures taken.

There are many threads that end with "I'll post pictures when I'm done and let everybody know how it went" only it never happens.
I didn't want My thread to end up the same way.

 

[Ninja_Lancer]

Shake down report:
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I have not finished re-building My calipers (I may use a different type) but...it was 55 out today so I had to ride it! 8-[
I used the Katana Master cyl and One caliper.

If you decide you don't want to go to the trouble of doing this fork swap mod. Do yourself a favor, get a master cylinder off of a late model anything! While not exactly "sportbike" brakes by any means, the master cylinder alone made the single disk caliper feel much stronger.

The first two stops I made had me worried. There was a strange hissing sound coming from the rear. You guessed It...the rear tire was locking up because the front brake was finally doing it's job!

I can't wait 'till I get two on there. \\/

Nice Kaw there in the back. I'm glad it made it into at least one pic here. Since it's as close as I can get to it right now. Being in Mo. right now and headed for Iowa in the morning...... Now what that has to do with GS dual discs I have no idea..........

 

[8trackmind]

Now what that has to do with GS dual discs I have no idea..........

It's killing ya looking at my crappy photography, huh?

 

[Nerobro]

This is why I went with the 650 fork. Now there's two 1980 gs550e's with dual front disks.

I used the original 550 master cylinder too. (smaller piston.. more pressure)