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1980 CX500 Custom
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Discussion Starter · #1 ·
New guy here from GA. I was just given a cx 500 and wanted to know if it was worth even taking it over. I don't know anything about the bike or cx 500s in general. I pick it up this weekend. I don't know the year but I do know it doesn't run. It's a project for me and my son. Or at least I hope it will be. I'm no mechanic or fabricator by any means but a bobber build is what were after. Am I being too ambitious? It's just really hard to turn down a free bike. So what am I up against? Are parts even available for these bikes? If I get it I'm sure I'll be on this forum alot asking stupid questions. I know I know....Google is my friend 😅
 

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1978 Honda CX500
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Hi ChrisDiehl .. I paid $999.00 for a non-running 1978 CX500 (I did get a whole spare engine - so there is that, and the bike was also rebuilt into a cafe racer already), so you are in better shape than myself. I think you have picked a biased forum to pose your question to, and most, including myself, on here will think this is a great bobber build project for you and your son. In the forum here you can find most/all of what you are looking for.
What year is your CX500? I believe one of the first things you will want/need to know is what you have for an ignition system. I believe (I know someone here will correct me if I'm, wrong) CX500s from 1978 to 1981 used a CDI - Capacitive Discharge Ignition, and those in later years used the TAI (Transistorized) ignition system. The older CDI system is prone to a few issues, from the CDI-specific coils on the stator to the CDI components themselves. The guy that sold me my bike said it was running less than a year ago and all I would need to do to get it running again is to replace the CDI with an aftermarket system (it had already been replaced once). I'm just about to get that system all connected and ready to test - so we shall see. The next thing you will want to know is the state of your stator system, The great news is that there are lots of exchangeable parts from other bikes and lots of aftermarket parts for just about everything you can think of. If you haven't googled CX500 bobber builds - please do so. Some of the bikes are really impressive. For instance; ’80 HONDA CX500: CAFE RACER! | Cx500 cafe racer, Cafe racer honda, Cafe racer motorcycle
I think the CX500 could be a lot of fun for you. You and your son can learn quite a bit if you just take it slow and don't expect too much too quickly.

:eek: CXP edit test. :eek:
 

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1978 Honda CX500
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I see after I posted that you said you don't know the year and for some reason, I can't edit the post right now. That's the first thing to figure out -- the VIN should help you with that. Also, look at the engine's serial number to see if the serial number range is in line with the frame's year of manufacture. In 40 years - the engine could very well have been swapped for a later or earlier version that doesn't match up with the frame. This may help:: Honda CX400 and CX500 Engine and Frame Serial Numbers (motofaction.org)
 

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The year of manufacture will be on a tag on the steering tube. Turn the handlebars to the right and look just forward of the gas tank.
 

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1978 CX500 "The Grub", 1983 GL650I "Nimbus"
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Before you make it a bobber, make it a runner. You don't want to put a lot of dollars and effort into a project that can't be finished, so concentrate on the functional issues first.
And once you get to know the bike, your vision might change, resulting in a machine you'll enjoy even more.
 

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In terms of a Father/Son project, free is a good place to start. As Randall said get it running first, learn the particulars of your machine. the time and money you spend is a very worthwhile investment.
 
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'84 CX650E that is evolving into a GL500
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Welcome to the forum. Please add your location and your bike's model and model year to your profile so that you don't have to remember to tell us every time and we don't have to keep asking when you forget (see Forum Settings link in my signature). As Rich mentioned, this information can be found on the VIN plate but note that it is the model year, not the date of manufacture that is important (most bikes sold in the US and Canada are manufactured in the last quarter of the year before the model year so that they can be in the distributor's warehouse in the beginning of the model year).

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). If your bike still has the original rubber brake line(s) (should be replaced every 2 or 3 fluid changes = 5 or 6 years) 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).

What Randall said about making it a runner first is just about the best advice anyone can give you about customizing any vehicle. It is tempting to dig in and try to make it look like something you saw a picture of and thought looked cool but a lot of vehicles that look nice at first glance have been modified in ways that actually work less well.
If you make it safe & reliable in more or less original condition 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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1978 Honda CX500
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Yeah ^^^ what they said; I think I kind of implied that without exactly saying it :). Definitely get it running and moving in whatever shape it's in first and then take on changing it (or not) to whatever you envision. By getting it running - you're most likely going to have to remove a bunch of parts (gas tank, side panels etc.), and get to know what makes it tick - what's essential and what's not. You will learn a lot about the bike and what you can and want/are-able to change or want to keep. The PO of my CX500 had a vision for it and I like 90% of his vision. I'm eager to get it running so I can make just a few small changes and call it my own.
 

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It's not about just getting it running, it's getting it running in a safe condition. ride it then think about changes. or just get the cutting wheel out and start chopping. your bike your choice
 

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Discussion Starter · #11 ·
Thanks guys. Getting it running is definitely good advice. The po had it running but he said that he thought the carbs were shot. I have a carb rebuild kit x2 on order as well as a battery and brake lines and an oil change kit and the boots for the manifold. I don't know anything about motorcycles but have always rode. I know less about carbs and engines in general so this should definitely be a learning experience.
 

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'84 CX650E that is evolving into a GL500
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Resist the temptation to replace any metal parts in your carbs with ones that come in the kits. The original jets, needles &c are almost always absolutely fine to use once cleaned properly but the ones in the kits are more often than not so far out of spec that they cause all sorts of problems.

It might be a good idea to order Larry's Carb Book (link in nolimitz' signature).

I've never heard if an oil change kit for one of these bikes but oil filters are pretty easy to find as Honda used the same filter in all of their 2 cylinder engines for years. Don't use automotive oil with an API rating higher than SF because they contain friction modifiers that can cause problems with wet clutches. The oil used in bike engines with wet clutches should be JASO-MA rated.

I'm not sure what you mean by "the boots for the manifold" but if you mean the intake runners that connect the carbs to the cylinder heads be warned that the aftermarket ones that have been on eBay and Amazon recently often have the rubber and metal parts misaligned so that they won't fit.

BTW: Don't forget to add your location and your bike' model and model year to your profile.
 

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What is the better way to do it?
 

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1978 CX500 "The Grub", 1983 GL650I "Nimbus"
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It depends on how much you value convenience.
 

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'84 CX650E that is evolving into a GL500
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I pick up a few bottles of oil for about $9 each when I'm in Canadian Tire (I'm sure there are places in the US that have a similar range) and I order the filters on eBay, 4 at a time (under $5 each). That's in $CAD so it would come to about $25 in US funds.
 

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His set had 3 rubber "O" rings, don't know if they need changed every time or not but if they do that would add to the cost also.
 

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I used to change the o-rings every time until I managed to pinch the big o-ring on my GoldWing (similar setup to the CX but larger) when putting it together. Big puddle of oil under the engine and no option except putting the old one back in. After that I decided they didn't need new o-rings every time so I started changing them every other time. Since I started buying filters that don't always come with new ones I change them if they look like they need to be changed, which isn't often.

The last time I remember changing an o-ring was when I replaced the engine in the GoldWing (long story involving better gearing for the sidecar). I actually replaced the o-ring with the one that came in the Athena gasket kit and a couple of weeks later I noticed oil dripping from the engine, which turned out to be coming from the oil filter housing. When I opened it up I found that the o-ring, which had protruded from the groove normally when I installed it, was now too thin to seal.
The one I replaced it with is still sealing several oil changes later.
I think I probably replaced the one in the GL500 engine before I put it into Eccles too but I'd have to check my notes.

FWIW, one of the machines where I worked had a counter that was driven by a plastic belt with a round cross section, which broke eventually. Instead of asking the boss to try to source the part (the manufacturer was long out of business) I brought in a used oil filter o-ring from the GoldWing and it worked perfectly. It was still working perfectly a decade later when I retired. I know that is working in tension instead of sealing but it is a pretty good indicator of how long something like that can last.

I shop online a fair bit these days and I hardly ever buy on Amazon because I can usually find the exact same thing elsewhere for less and I can almost always find what I am looking for easier somewhere else (if they would fix their search function and police the keywords that sellers use it might be better but as it is it is a terrible experience).

As for buying oil (or any other liquid for that matter) online, you must know that a significant part of the price is the cost of shipping ("free" shipping just means that the price has been increased to cover the cost of shipping) so buying online is almost always second only to buying it at a bike shop.
Besides, I remember being taught that step #1 of an oil change is driving to the store for the supplies so that the engine is fully warmed up and the old oil will drain better. Yes, I know that isn't always possible in the real world (I often have to take a ride to warm the engine because I bought the oil weeks before I needed it) but if you buy the oil online it can never happen.
 

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His set had 3 rubber "O" rings, don't know if they need changed every time or not but if they do that would add to the cost also.
Some filters come with both o-rings.
I usually reuse them, so I've been accumulating spares.
 
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