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Discussion Starter #1
Hi there, new member here.

Almost time to put away the bike here in Montreal.
Bought this bike September 2018, rode it for a couple months, put it away. Got it out this year, changed oils and rode it almost as-is all year, just to enjoy it before working on it. (Changed squealing rear brake shoe but that's it)
cx500_01.jpg

I figured out it would be time to upgrade some stuff for 2020. I want to get to know my own bike since it's a second-hand bike from a second hand seller. Been chatting with the previous owner a bit, but I don't have a lot of info on the bike and it bothers me.
Would be starting with the front, and slowly getting to know each component and change the faulty ones.

Been reading a lot on here trying to gather as much information as possible for future needs, but i can't quite find this precise info right now.

The front brake power on my 1982 cx500c (single disc dual caliper) is not the best fora +- 500 pounds bike and I'm wondering what I will do to improve this. I know upgrading to a SS brake line is a simple and wise choice...
But I'm telling myself: Why not take some gl500 dual disc dual caliper forks, swap them, then upgrade to SS brake lines? I could skip a lot of work, triple tree, all-balls bearings, cutting forks, shims, etc., etc. Plus I get to keep the reverse comstars and the global look of my bike, while doubling my braking power.

This all seems so simple, yet I can't find any info on if it's been done before. So maybe it's not that simple after all.

Motofaction seems to say it's possible. At least for the fork diameter. But there is a bunch of missing info for the CX

CX500c_gl500_fork_swap.jpg

This would be the donor bike. A 1981 gl500. I plan on asking for more photos and infos on the bike since we don't even see the calipers from here. But i wanted to see if my idea is even possible before bothering the seller.

Screen Shot 2019-10-16 at 1.17.59 PM.png


So, my question would be: Can I just swap the forks from the said bike to my cx500c, yes or no? ( I mean, forks, brake line, front wheel etc. but keeping the cx500c triple tree. Just sliding the forks in and reconnecting brakes)

The follow up would be: If I can't swap the gl500 forks in the cx500c triple tree, is it just possible to swap the whole gl500 front end in the cx500c frame?


Hope that makes sense.
Thanks in advance!

Julien
 

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I swapped a front end off an '81 CB750F onto my '80 CX500D project and it stops very well now ?. This took a bit of shimming, adjusting stops etc. I suspect a full swap of the GL onto the CX would require the same. But if the fork tubes are the same diameter you might be in luck. Personally I'd still recommend rebuilding everything, forks, calipers, master, and of course braided lines.
 

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My 2 cents... I have both an 82 gl500i(naked) and an 82 cx500c, ss lines, new mc's and refreshed callipers on each of them. There is really no noticeable difference in stopping power. The single disc is larger diameter than the duals I believe is the reason. Somewhere I read the dual disc set up gives better fade resistance, maybe useful in the twisties or 2 up with lots of gear in the mountains (or both at once), but not ordinary street riding I do. I would go with one of the swaps to a more modern front end if I wasn't content with what I have.
 

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One other consideration: Trail (the distance between where a line though the steering head and a vertical line through the axle would meet the ground)

The CX500C's forks have the axle mounted in front of the forks. This was pretty common on factory customs because it allows more rake (the "chopper" look) without having excessive trail that would make it hard to steer at low speed.
The GL500's axle is mounted on the bottom of the forks (in the centre line of the forks) so even if every other measurement was the same you would increase the trail by 30mm or more. Also, I expect that the bike's original fender wouldn't fit because the wheel was moved to the rear by that much.

For reference, My '83 GL1100 came with 135mm of trail, which was fine on 2 wheels but made for very heavy steering after I added the sidecar. After wrestling with it for a few years I bought a set of leading axle forks from a CB650SC and rebuilt them to suit the loads (longish story so I won't go into detail here). I figure they moved the front wheel forward by about 35mm, decreasing the trail by the same amount, bringing it pretty close to the 100mm of trail all of the other sidecar outfits I've had have had and making the steering much easier.

This pic shows the before on the left and after on the right. Note how much more room there is between the fender and the rad, even though the front end of the bike is slightly lower (you would be changing in the opposite direction).
 

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Discussion Starter #7
I swapped a front end off an '81 CB750F onto my '80 CX500D project and it stops very well now ��. This took a bit of shimming, adjusting stops etc. I suspect a full swap of the GL onto the CX would require the same. But if the fork tubes are the same diameter you might be in luck. Personally I'd still recommend rebuilding everything, forks, calipers, master, and of course braided lines.
That swap looks pretty good. The amount of work needed to be done is a little too much for a start. That is the kind of swap I try to avoid. Not having a lot of tools nor a garage to work in, those type of task seem a little over the top.

One other consideration: Trail (the distance between where a line though the steering head and a vertical line through the axle would meet the ground)

The CX500C's forks have the axle mounted in front of the forks. This was pretty common on factory customs because it allows more rake (the "chopper" look) without having excessive trail that would make it hard to steer at low speed.
The GL500's axle is mounted on the bottom of the forks (in the centre line of the forks) so even if every other measurement was the same you would increase the trail by 30mm or more. Also, I expect that the bike's original fender wouldn't fit because the wheel was moved to the rear by that much.

For reference, My '83 GL1100 came with 135mm of trail, which was fine on 2 wheels but made for very heavy steering after I added the sidecar. After wrestling with it for a few years I bought a set of leading axle forks from a CB650SC and rebuilt them to suit the loads (longish story so I won't go into detail here). I figure they moved the front wheel forward by about 35mm, decreasing the trail by the same amount, bringing it pretty close to the 100mm of trail all of the other sidecar outfits I've had have had and making the steering much easier.

This pic shows the before on the left and after on the right. Note how much more room there is between the fender and the rad, even though the front end of the bike is slightly lower (you would be changing in the opposite direction).

Thanks a lot for that info. I did not think about any of those things (axle mounting, trail and rake.)

Since I stumbled upon this 100$ gl500 frame and fork I thought about doing the swap. But I think I'll stick with SteveH plan and just upgrade my own fork since I'm mostly a city commuter.
Changing the fork oil, braided SS line, new pads and probably a MC rebuild kit might just be enough after all.

Thanks a lot for your input, really appreciated.
 

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If you swap your single piston caliper for a dual piston coupled with a ss brake line and your braking will be much improved. I like your plan but this is cheaper and easier.
 

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Discussion Starter #9
If you swap your single piston caliper for a dual piston coupled with a ss brake line and your braking will be much improved. I like your plan but this is cheaper and easier.
I already have a dual piston caliper, but I'll be shopping for a SS brake line for sure!

Thanks
 

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I already have a dual piston caliper, but I'll be shopping for a SS brake line for sure!

Thanks
Anyone know if the dual piston caliper was stock on an 82' C? My 81' D had a single. Just curious.
 

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If you haven't already rebuilt the caliper, master cylinder and forks I highly recommend that you do them as soon as you can. I would recommend that for anyone buying a used bike but especially one that is 37 years old.

BTW: Welcome to the forum and welcome to the world of antique vehicle ownership (they own us, not the other way around). Your bike has had 37 years of Previous Owners who may or may not have done the maintenance necessary to keep it safe & reliable so it is highly recommended to download the Factory Shop Manual for your model (available through the CX Wiki - link in my signature) and go through all of the service procedures, regardless of whether your bike has reached the specified mileage.

I also recommend looking on all rubber parts with suspicion because rubber does not age gracefully. Check the date codes on your tires and replace them if they are over 5 years old no matter how good they look & feel because old rubber simply cannot flow around the irregularities in the asphalt well enough to grip, especially if it is cool or wet.

Your bike's original rubber brake line(s) should have been replaced every 2 or 3 fluid changes (= 5 or 6 years) shopping for modern stainless braided one (they last practically forever and double the life of the fluid) is a very good idea. It makes sense to rebuild the caliper and master cylinder and install the new brake line at the same time so that you only have to bleed the system once.

If you don't have a garage do you at least have room for a garden shed? Most building supply places sell kits for 10'x10' sheds that at least keep the weather out while you work on it. If that isn't possible you may be able to join a co-op motorcycle workshop in your area. They usually offer heated, well lit shop space (& sometimes tools, lifts &c) for quite reasonable rates. I read an article about them in Mojo a few months ago but I can't remember if they mentioned Montreal.
 

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... and probably a MC rebuild kit might just be enough after all.
You may find it less expense to buy an aftermarket master cylinder than to buy a rebuild kit
for the OEM master cylinder.
 

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... and probably a MC rebuild kit might just be enough after all.
You may find it less expense to buy an aftermarket master cylinder than to buy a rebuild kit
for the OEM master cylinder.
Agree with this. I have ordered a couple aftermarket master cylinders from David Silver Spares and they work great.
 

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1-BTW: Welcome to the forum and welcome to the world of antique vehicle ownership (they own us, not the other way around). Your bike has had 37 years of Previous Owners who may or may not have done the maintenance necessary to keep it safe & reliable so it is highly recommended to download the Factory Shop Manual for your model (available through the CX Wiki - link in my signature) and go through all of the service procedures, regardless of whether your bike has reached the specified mileage.

2- I also recommend looking on all rubber parts with suspicion because rubber does not age gracefully.

3- Your bike's original rubber brake line(s) should have been replaced every 2 or 3 fluid changes (= 5 or 6 years)
1- Yeah I downloaded everything i could from the wiki. Already had/have some thermostat/slight overheating problems so I tried to learn what was up with that and ordered some pieces already (thermostat, rad fan, temp sending unit, o-rings). That's the part that bothers me the most. Like you said, I have no clue of who did what when. Or even if somebody did something ever. I know the tires are soon to be changed. They ain't no 1980's tires though.

2- I saw a couple of faulty rubber pieces and some of them start to crack a little. Like the rubber part on the intake manifold. Will definitely look into that while getting to know the bike this winter.

3- That is definitely the first thing I'll be doing. Not even sure if that has ever been done. Can't know.

I'll be renting a garage in the winter to store my bike. That's why I wait until then to do the bigger stuff. Working on the sidewalk is doable. I mean I did a couple of things on the rad / a couple rad flushes there. But it annoys me a little.

Agree with this. I have ordered a couple aftermarket master cylinders from David Silver Spares and they work great.
Thanks fot the hint. Will look into this. I tend to find the aftermarket ones a little «too much» but I'll try to find something aestetically pleasing.


Really appreciated guys.
 
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