Adapting Rear Master Cylinder from GL1800 to GL1100

cross over parts from other wings, hondas, or any other parts sources that can be used on our wings.

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Easter
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Adapting Rear Master Cylinder from GL1800 to GL1100

#1

Post by Easter »

I am rebuilding/customizing a GL1100 and have been working through a long list of issues but one of the more frustrating has been the rear brake master cylinder. I have three now and although perhaps it is a reflection of my skill level I have not been able to get any of them to work properly. Since these parts are now 30+ years old and often left unused for decades they are often thoroughly gunked up to say the least.

I decided to look for something newer that could be substituted and decided to try the GL1800 series since they are only a few years old and plentiful and often cheap. I bought a nice clean one from a 2009 bike complete with hydraulic fluid for $35 including shipping. Less than the price of a rebuild kit.

It turns out the conversion is quite simple. The GL1800 has a slightly larger piston and the mounting tabs are in different locations and the threaded shaft must be cut down but a reasonably skilled person with ordinary hand tools can make an adapter and install the new master cylinder in a couple of hours. Some hand fitting is required and this gets tedious with a fully assembled bike.

After a test ride through town today, I am quite satisfied with the function and do not feel the larger piston/cylinder will create any problems.
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Bikes at present:
80 GL1100 Interstate: Now a Cafe Racer called DRAGON WING.
75 XL 250 just for fun
83 XL 600r with a 2004 XR650L engine
And a couple of older BMW GS adventure bikes (keep hoping for an adventure!)
A fleet of parts bikes awaiting resuscitation or customization or abandonment :IDTS:
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Re: Adapting Rear Master Cylinder from GL1800 to GL1100

#2

Post by Easter »

Unfortunately, I forgot to photograph the reservoir in place but it is unchanged from the original configuration. The GL1800 hose is about a 1/2 inch shorter but the mounting adapter on the cylinder itself is long enough that the tube can be slid off a bit to create more length. The original GL1100 reservoir must be used since the mounting angle is different for the GL1800 and the tube comes out of the side rather than the bottom as on the 1100. It is also smaller in diameter but I was able to push the 1100 reservoir onto the tube without much trouble. A larger clamp is required so put it on first or you will be taking it back apart as I did!

It was relatively easy to prime. I left the banjo bolt loose until I had fluid seeping out, then tightened it and opened the bleeder valve at the caliper. A small tube placed over the bleeder valve goes into a can of brake fluid to prevent suction from pulling air back into the line. In a few minutes I had the brake bled and was ready for a ride. After a few miles warming up the pads and seating them, the rear brake felt just fine.
Bikes at present:
80 GL1100 Interstate: Now a Cafe Racer called DRAGON WING.
75 XL 250 just for fun
83 XL 600r with a 2004 XR650L engine
And a couple of older BMW GS adventure bikes (keep hoping for an adventure!)
A fleet of parts bikes awaiting resuscitation or customization or abandonment :IDTS:
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Re: Adapting Rear Master Cylinder from GL1800 to GL1100

#3

Post by CYBORG »

nice job
1978 custom GL1000
1977 custom with 1200 engine
1985 gl1200
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Re: Adapting Rear Master Cylinder from GL1800 to GL1100

#4

Post by Sagebrush »

Good to know. Nice work.
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Re: Adapting Rear Master Cylinder from GL1800 to GL1100

#5

Post by Brant »

Good info, thanks.
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Re: Adapting Rear Master Cylinder from GL1800 to GL1100

#6

Post by chewy999 »

Useful to know for when the time comes. :partytime
Previous Rides,
1980 CB250N Good to learn on
1981 CX500 good mid range tourer, went to Austria on it!
1983 GL1100C Pride and joy, sold when I bought my 1st house, big mistake
1985 GL650 Silverwing another mistake, horrible bike
1986 CBX550 Good commuter
1989 Suzuki GS750 (1976) cheap and cheerful until a dog ran out in front of me on Xmas Eve, 1991
Current bikes
2010 CB1300 back on a bike after 19 years, two divorces, children grown up etc
1980 GL1100 NOW ON THE ROAD, still use CB1300.
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Re: Adapting Rear Master Cylinder from GL1800 to GL1100

#7

Post by westgl »

Hey Easter,

You have had some time to test ride and get a good under standing as to the Pro's & Cons, of going to this conversion.

1. Do you get any brake lockup, Front or Rear?
2. What about panic stop, can you lock either wheel larger piston means more brake power?
3. Any problems that you have encountered?
4. How does the foot brake feel now? any excess foot pedal play?
5. Are the brake similar to the way they were stock?

I have a 1983' GL1100 with linked brakes That i will be testing this on.
Easter wrote:I am rebuilding/customizing a GL1100 and have been working through a long list of issues but one of the more frustrating has been the rear brake master cylinder. I have three now and although perhaps it is a reflection of my skill level I have not been able to get any of them to work properly. Since these parts are now 30+ years old and often left unused for decades they are often thoroughly gunked up to say the least.

I decided to look for something newer that could be substituted and decided to try the GL1800 series since they are only a few years old and plentiful and often cheap. I bought a nice clean one from a 2009 bike complete with hydraulic fluid for $35 including shipping. Less than the price of a rebuild kit.

It turns out the conversion is quite simple. The GL1800 has a slightly larger piston and the mounting tabs are in different locations and the threaded shaft must be cut down but a reasonably skilled person with ordinary hand tools can make an adapter and install the new master cylinder in a couple of hours. Some hand fitting is required and this gets tedious with a fully assembled bike.

After a test ride through town today, I am quite satisfied with the function and do not feel the larger piston/cylinder will create any problems.
1983 GL1100I Beige was an Interstate, Now Naked, Refresh & needs repaint
1984 GL1200A Naked 4Cyl.Valkyrie, Single Valk. seat & Valk. Gas Tank
1986 GL1200 Naked Hotrod with some old school in the mix (Completely gone through) Better than new
1988 GL1500 76 k miles, Naked 6cyl. building into a HotRod trike. (Under Construction)
1999 GL1500 45K miles Runs excellent
2006 M109R 1800cc Naked Reverse Trike
previous bikes, (there are way too many to list)
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Re: Adapting Rear Master Cylinder from GL1800 to GL1100

#8

Post by spiralout »

Wish I'd come across this post before spending months and $125+ hunting down an original that only took 5 days of soaking to get the circlip and washer out so I could start on the old frozen piston... :( :( :( .
westgl wrote:Hey Easter,

You have had some time to test ride and get a good under standing as to the Pro's & Cons, of going to this conversion.

1. Do you get any brake lockup, Front or Rear?
2. What about panic stop, can you lock either wheel larger piston means more brake power?
3. Any problems that you have encountered?
4. How does the foot brake feel now? any excess foot pedal play?
5. Are the brake similar to the way they were stock?
I'm curious about these, too. How's it working out, Easter?
Chris
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Re: Adapting Rear Master Cylinder from GL1800 to GL1100

#9

Post by jimmyz3286 »

Nice write up if I can work it in I may have to do this since I am in the middle of a build.
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Re: Adapting Rear Master Cylinder from GL1800 to GL1100

#10

Post by irishcarbomb »

I just did this...took about an hour and works great. Used a master from a 2001 gl1800 same as pictured in this thread.

I never rode with stock brakes so I cant compare the feel, but its pretty close to what my sportbike is like. If not better. I wish I would've just done this instead of hunting down a second M/C...cost about the same as a rebuild kit.


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1983 GL1100 Fuel Injected Turbo Build Thread
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Re: Adapting Rear Master Cylinder from GL1800 to GL1100

#11

Post by 82aspy »

Easter wrote:I am rebuilding/customizing a GL1100 and have been working through a long list of issues but one of the more frustrating has been the rear brake master cylinder.
what year 1100?
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Re: Adapting Rear Master Cylinder from GL1800 to GL1100-83 i

#12

Post by 82aspy »

i know of one (& only) other recent 83 conversion that i don't think has been tested much, comments are in this thread
I just did this...took about an hour and works great. Used a master from a 2001 gl1800 same as pictured in this thread.

I never rode with stock brakes so I cant compare the feel, but its pretty close to what my sportbike is like. If not better. I wish I would've just done this instead of hunting down a second M/C...cost about the same as a rebuild kit.

Pics in my build thread.
http://ngwclub.com/forum/viewtopic.php?p=562670#p562670

westgl wrote:Hey Easter,

You have had some time to test ride and get a good under standing as to the Pro's & Cons, of going to this conversion.

1. Do you get any brake lockup, Front or Rear?
2. What about panic stop, can you lock either wheel larger piston means more brake power?
3. Any problems that you have encountered?
4. How does the foot brake feel now? any excess foot pedal play?
5. Are the brake similar to the way they were stock?

I have a 1983' GL1100 with linked brakes That i will be testing this on.
Easter wrote:I am rebuilding/customizing a GL1100 and have been working through a long list of issues but one of the more frustrating has been the rear brake master cylinder. I have three now and although perhaps it is a reflection of my skill level I have not been able to get any of them to work properly. Since these parts are now 30+ years old and often left unused for decades they are often thoroughly gunked up to say the least.

I decided to look for something newer that could be substituted and decided to try the GL1800 series since they are only a few years old and plentiful and often cheap. I bought a nice clean one from a 2009 bike complete with hydraulic fluid for $35 including shipping. Less than the price of a rebuild kit.

It turns out the conversion is quite simple. The GL1800 has a slightly larger piston and the mounting tabs are in different locations and the threaded shaft must be cut down but a reasonably skilled person with ordinary hand tools can make an adapter and install the new master cylinder in a couple of hours. Some hand fitting is required and this gets tedious with a fully assembled bike.

After a test ride through town today, I am quite satisfied with the function and do not feel the larger piston/cylinder will create any problems.
"there is a Darwinian element"
Yoda said, "There is no try or not try; there is only do or don't do."
=====================
ngw quotes anim-cheers1 - \ "I will strip the beast" \ "the swingarm is just a hunk of metal" \ "gonna maybe ...dunno yet" \ "It's never done, thats the fun." \ "something about this site brings me back"
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Re: Adapting Rear Master Cylinder from GL1800 to GL1100

#13

Post by Brant »

Ok so I got an 1800 master cylinder and want to do this swap/upgrade. But the hard line that goes in to the 1100 rear master on my 83 has a line nut on it. How do I swap it to a banjo fitting? I'm guessing I cut the hard line and slip a rubber brake line with a banjo fitting on the end end, over the hard line and secure with a clamp of some type??

Well I just checked a couple places here in town and they said they can't do it. Don't have the banjo fitting. NAPA said they can't crimp the fittings to the lines, a DOT thing.
83 GL 1100 bagger
78 GL 1000 naked
ALL WE WANT TO DO IS DRINK OUR ESPRESSO, RIDE OUR MACHINES, AND NOT BE HASSLED BY THE MAN
Owning a motorcycle is not a matter of life or death. It's much more important than that.
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Re: Adapting Rear Master Cylinder from GL1800 to GL1100

#14

Post by CYBORG »

I'm not a fan of clamps on brake line fittings. I would have a new line made, with the correct ends
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1985 gl1200
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Re: Adapting Rear Master Cylinder from GL1800 to GL1100

#15

Post by Brant »

Found a couple on line places. Guess I'll get it done but thought it would be a little quicker swap. Shoulda checked it out a little more first.
83 GL 1100 bagger
78 GL 1000 naked
ALL WE WANT TO DO IS DRINK OUR ESPRESSO, RIDE OUR MACHINES, AND NOT BE HASSLED BY THE MAN
Owning a motorcycle is not a matter of life or death. It's much more important than that.
"Don't sweat the little things, guys, take care and appreciate all that you have around you!" - Fewman
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