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1979 CX500
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Discussion Starter · #1 ·
This thing is.. something. An abandoned project acquired from a friend of a friend, and my first bike.

It starts and runs fine, might tackle the bypass this winter, might leave it til next winter, we'll see what happens.

Instrument cluster isn't from a CX500 (at least not a 79) as far as I can tell, not sure why PO took the time to wire it in but just left it zip tied onto the bars since the plate doesn't match up.

Next on the agenda is sort out the sticky throttle, shep method the mech seal (ordered from Murray last week), and get the battery etc tucked under the seat (went with the pre-made tray from CX500parts.com).
Tire Wheel Fuel tank Automotive fuel system Vehicle


PO had a lithium battery on it (taped to the frame), not sure for how long. I need to replace it with a smaller one in order to fit it under the seat - I've read both sides of the lithium conversation, seems like it might catch fire, or it could be fine for years?

What I thought would be 'some easy cosmetic work' quickly turned into a 'tear down and rebuild' situation I think
 

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'84 CX650E that is evolving into a GL500
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Welcome to the forum and welcome to the world of antique vehicle ownership (they own us, not the other way around). Your bike is about 4 decades old and may or may not have had all of 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 (old rubber simply cannot flow around the irregularities in the asphalt well enough to grip, especially if it is cool or wet). I see in the pic that your bike still has the original rubber brake line, which should have been replaced every 2 or 3 fluid changes (= 5 or 6 years) so I recommend shopping for modern stainless braided ones (they last practically forever and double the life of the fluid). And don't forget things like the rad hoses and the boot between the engine and swingarm (they can crack on the bottom where you don't see it).

The best advice anyone can give you about customizing any vehicle is to get it safe & reliable in more or less original condition (or at least as close to that as is reasonable) and use it for a while before you start making any changes so it can tell you what changes it needs to make it do what you want/need better. That approach almost always results in something you actually want to keep and use but making changes based on style or on what someone else (who may or may not really understand how the changes affect the way it works) has done often results in a piece of expensive yard art that you can't stand sitting on for more than a few minutes and might even be dangerous.
 

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What I thought would be 'some easy cosmetic work' quickly turned into a 'tear down and rebuild' situation I think
Any time someone else has monkeyed with something you should just be prepared for the worst. There is usually a reason people abandoned a project. You sound like you're up to the task and there are the most knowledgeable people on the subject right here to help you. If you haven't already, download the FSM here:
Factory Service Manual - Honda CX and GL Wiki (motovillage.org)
and peruse that site as well as this one:
The Honda CX and GL 500 and 650 family of motorcycles (motofaction.org)
If you delve into working on the carbs here is another resource:
CX500/Gl500 Carb book (donlhamon.com)

Cheers!
 
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'84 CX650E that is evolving into a GL500
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At least this one was mangled by amateurs. Have a look at this one that was cobbled together by a "professional" bike builder
 

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I remember that one, what an absolute mess! I always tell people that being a "professional" only means they get paid for it, doesn't mean they know what they are doing, or care.
 
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1979 CX500
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Discussion Starter · #8 ·
Looking for some wisdom on where to start. Lithium battery and new reg/rec will go on tomorrow. For bigger winter project would you overhaul all wiring and swap new gauges, headlight, blinkers, etc. or would it be better to triple/quad bypass. Since it's about to rain for 8 months straight where I live does it make sense to do the aforementioned projects all at once and completely tear down, paint, and rebuild?
 

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If you decide to do the triple/quad bypass make sure that you have all parts required on hand before you start the teardown.

Do you have a step by step plan for your build or are you just winging it?
 

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1979 CX500
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Discussion Starter · #10 ·
No plan as of yet, still debating on whether I want to tear down and rebuild this - in which case I'd probably want to get something in better shape so I can enjoy riding while having a project bike. Might just get this one into decent riding shape and call it good though. I've never done metal fab or welding, and have never really worked on engines besides basic routine maintenance so I'm wary of getting in over my head even with all the good info available.

Kind of curious what kind of $ I'd need to spend to have a professional do the bypass over the winter?
 

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Do you have a reason for doing the bypass? Has the stator failed, is the cam chain past its useful life? If not, I'd suggest leaving it alone. Is the bike running? How are the tires, brakes etc? Get the bike running and riding before digging in too deep.

Many shops won't work on a bike this old. What are typical shop rates in your area? I'd expect a shop to book at least five hours, plus mark up on the parts.
 

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1979 CX500
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Discussion Starter · #12 ·
Do you have a reason for doing the bypass? Has the stator failed, is the cam chain past its useful life? If not, I'd suggest leaving it alone. Is the bike running? How are the tires, brakes etc? Get the bike running and riding before digging in too deep.

Many shops won't work on a bike this old. What are typical shop rates in your area? I'd expect a shop to book at least five hours, plus mark up on the parts.
Everything seems to be running fine, idle seems smooth enough, starts up fine - hence maybe tacking the wiring this winter instead, I didn't know if general advice on these was to immediately do the bypass before something does fail, given the age.

Shop rates are 100-150/hr. Brakes and tires are good, have spun it around the neighborhood a few times but need to do the mech seal before riding on it any more. Might be the only thing it needs but I'm worried that I'm missing something. I have a friend who did a full custom build take it for a spin just to cover my bases.
 

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'84 CX650E that is evolving into a GL500
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Looking for some wisdom on where to start.
Do the minimum to get it safe to ride and use it a bunch. As I said before, it will tell you what needs to be changed to make it into what you need it to be and that will always give you a batter result than making style based changes.

And with those ancient rubber lines the brakes are at best passable.
 

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1979 CX500
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Discussion Starter · #14 ·
Midway through the mech seal replacement, I'm noticing a bit of wear / breakdown of the metal around where the impeller spins - should I be worried about this or normal wear for a bike this age?
Wheel Tire Automotive tire Motor vehicle Alloy wheel
 

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1979 CX500
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Discussion Starter · #16 ·
In a plot twist I'm just now realizing I had to use a screwdriver to get the impeller off. I just gently twisted it a bit (so I thought). Today was not my sharpest mental day apparently, but I did get the mech seal replaced and everything seems fine for now 😂. First real thing I've done on a motorcycle in my life so if the bike lives through it and forgives me that'll be a win.
 

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1978 CX500 "The Grub", 1983 GL650I "Nimbus"
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Folks need to be careful prying off the impeller. The camshaft it's attached to is very brittle and doesn't tolerate much lateral loading. Use a pair of levers, if you must.
 
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Folks need to be careful prying off the impeller. The camshaft it's attached to is very brittle and doesn't tolerate much lateral loading. Use a pair of levers, if you must.
Yes. When i took the water pump cover off of mine the cam came "pre broken", I'm sure due to what you just stated. I'm also quite sure that's why the bike was abandoned...
 
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