Honda CX 500 Forum banner
1 - 20 of 86 Posts

·
Registered
Joined
·
124 Posts
Discussion Starter · #1 · (Edited)
I've got big plans for this '81. I bought it for $200. The engine has 70k miles, turns over but is non-running. The carbs are gunky, the forks leak, the compression is down in the 120s, some of the electrical system appears to be fried, it's missing a LOT of parts, and it's just ugly in general - seems like a good candidate for a total re-imagining to me!

Here's what I'm starting with. The previous owner had stripped off all the fairings & panels and cut up a custom tailpiece from a Sportster fuel tank, and fabbed a shock mount for a Ducati 999 rear shock:

Land vehicle Vehicle Motorcycle Alloy wheel Motor vehicle


I plan to go a bit further with this than just a seat pan and clip-ons. I'm stripping the bike down to nuts & bolts, and here's some of the work I have in store for the next few months:
- Mikuni carbs, pods, true dual pipes (lose the H box), mufflers
- Grind the cam to squeeze out a couple more HP
- Structural strengthening of PO's custom shock bracing with steel bracing
- Remove the engine, inspect & deep-clean, adjust valves, possibly replace piston rings, water pump, stator, & cam chain if needed upon testing
- Replace all rubber parts due to age and the bike sitting for years
- Powdercoat the frame, swingarm, wheels
- Rebuild forks & stiffen with spacers
- Bigger front brake caliper or more modern disc if needed after testing
- Modern lights, gauges
- CX500 deluxe fuel tank

I'll be using this thread to field the issues I run into along the way. This is a great forum so far!

Cheers,
--Carter
 

·
Registered
Joined
·
24,568 Posts

·
Registered
Joined
·
124 Posts
Discussion Starter · #3 · (Edited)
do the dentl timing chain inspection and see if you have any adjustment left if you do

just oil it up change all fluids and fire it up with the new carbs

CX500 GL500 650 Global ? View topic - Dental Mirror Cam Chain Inspection.
I'm thinking about pulling the engine apart just for the fun of it, and will inspect the chain at that time. I get peace of mind looking at things rather than assuming everything is fine just because it's running - call it an OCD personality...
The mirror idea looks good though - thanks!
 

·
Registered
Joined
·
725 Posts
Welcome to the forum Carter,
Looks like you have a pretty good starting point there, post plenty of pics during your build. We all luv pics on the forum.
Can't wait to see what she'll look like done.
When you get the chance put the bikes year and model on your signature line, as it helps members in diagnosing any issues and
add your location to your profile as there may be a member close by that can help you out.

I plan to go a bit further with this than just a seat pan and clip-ons. I'm stripping the bike down to nuts & bolts, and here's some of the work I have in store for the next few months:
- Mikuni carbs, pods
Murrayf is the member you want to talk to about Mikuni carbs and pods.

Ride Safe & welcome aboard
 

·
Registered
Joined
·
124 Posts
Discussion Starter · #5 · (Edited)
Welcome to the forum Carter,
Looks like you have a pretty good starting point there, post plenty of pics during your build. We all luv pics on the forum.
Can't wait to see what she'll look like done.
When you get the chance put the bikes year and model on your signature line, as it helps members in diagnosing any issues and
add your location to your profile as there may be a member close by that can help you out.


Murrayf is the member you want to talk to about Mikuni carbs and pods.

Ride Safe & welcome aboard
Thanks!
I've spent all day today assessing the bike, planning the build I want to achieve, and researching/ordering parts (including the Mikunis, pods, & upswept exhaust extensions from Murray). I'm going to tear the bike apart tomorrow, and I should receive the bulk of the parts I need by next weekend - just in time to have everything torn down and ready for powdercoating. Engine work will happen during the time that the powdercoating is underway, and hopefully within a week of getting everything back I'll be ready to start assembling. Admittedly optimistic, but it would be nice to have this bike ready for trials within a couple months.
I suppose for me, half the fun is in the planning stage, and the challenge of meshing all the gears of a project together with minimal waitin-around time is an alluring one.

The tricky part is going to be the fab work, since I'm not good with metal working, and I could use some tips on how to take the tail piece the PO fabbed from a Harley tank and curl the leading edge inward 90 degrees to the centerline such that it creates a lip. Any tips?

Here's some more pics what I'm starting with:
Land vehicle Vehicle Tire Automotive tire Motorcycle

Land vehicle Vehicle Motorcycle Fuel tank Automotive tire

Motorcycle Vehicle Motor vehicle Automotive tire Auto part
 

·
Registered
Joined
·
124 Posts
Discussion Starter · #6 · (Edited)
The Tear-down Begins:

The engine came down very easily, and thankfully the driveshaft slid right out without much fuss. I will need a new dust boot though - does anyone know where I can find a new one?
Engine Auto part Vehicle Fuel line Motor vehicle

Overall the engine looks in good condition, although corroded and dirty. A thorough inspection of the radiator will follow to determine if it's still fit for service.
Land vehicle Vehicle Motorcycle Motor vehicle Automotive tire

Auto part Engine Automotive engine part Vehicle Carburetor

Engine Auto part Automotive engine part Vehicle Machine

Motor vehicle Auto part Engine Vehicle Automotive tire

I'm sure there's a bit more fun history here I've yet to learn of...
Sand Rock

The teardown of the controls was relatively straightforward as well, except I don't understand some of the routing choices. When I reinstall I'm gonna have to route it all through the fuel tank tunnel instead of between the engine and the frame.
Land vehicle Vehicle Motorcycle Automotive tire Tire

Land vehicle Vehicle Motorcycle Tire Rim

The only problem I ran into was in removing the front forks. Both of the bottom-most bolts on the starboard fork that fasten the axle clamp were stripped in such a way that the nut just spun on the bolt and didn't go anywhere. I had to cut the suckers off and order new nuts & bolts :-/ Does anyone know how to properly remove those bolts from the bottom of the fork? I can't get a good enough grip to spin em and it doesn't look like they can be removed any other way than just pure brute strength.
Vehicle Bicycle wheel Rim Spoke Bicycle part


All in all, a successful day! I'll be working on the radiator, carbs, and forks this week, and in the meantime will hopefully receive my order of structural steel so I can weld on the supports I need for the rear shock and seat pan. Then it's off to powdercoating!
 

·
Registered
Joined
·
124 Posts
Discussion Starter · #7 · (Edited)
Bought this old CX500 Deluxe fuel tank from a guy on Craigslist for 50 bucks. Not a dent on it, and no rust inside because he had the foresight to coat it with WD-40! Good thing too, because the ones on Ebay are a small fortune, and the tank that came standard on this bike is a visual sin.
Helmet Motorcycle helmet Personal protective equipment Headgear Sports equipment

Strip it
Auto part Gas Automotive tire Fender

Sand it
Fuel tank Automotive fuel system Fender Vehicle Auto part

It'll take some work with a dual-action sander to get the rust spots out and really put a nice bare-metal shine on it. I'm not currently planning on clearcoating the tank because I want to retain the look of bare metal, which I would lose if I coated it with anything. Does anyone know of a good alternative that I can spray on here to maintain the bare metal look but protect it from rusting?
 

·
Registered
Joined
·
185 Posts
Nice project you got going here and looks like you work fast too. Look forward to seeing the progress.
On your tail piece pics, is it all the way back. Just wondering cause seems like a tight fit between it and the tank to be sit comfortable. Later.
 

·
Registered
Joined
·
124 Posts
Discussion Starter · #10 · (Edited)
Nice project you got going here and looks like you work fast too. Look forward to seeing the progress.
On your tail piece pics, is it all the way back. Just wondering cause seems like a tight fit between it and the tank to be sit comfortable. Later.
Thanks! I'm hoping to be done in a couple months, but it's already clear I'll be waitin a lot on back-ordered OEM parts :-/

You're right about the tail piece. I'm going to re-cut it to add room for a bigger seat. Does anyone on here know a good way to bend the leading edge of the steel inward 90 degrees (perpendicular with the frame/wheels) so it would become a good mounting surface for a butt-stop? I'm no good at metalworking and could use some pointers...
 

·
Registered
Joined
·
124 Posts
Discussion Starter · #11 · (Edited)
I have been out of town on business off-and-on for the last couple weeks, but I returned to find that my parts had arrived!!
Everyday carry Tool Groupset

- Mikuni carbs, pod filters, and mounting equipment courtesy of Murray - as well as his upswept exhaust extensions
- New stator from RMstator
- Piston rings from David Silver Spares
- OEM radiator fan replacement from honda4u.com
- Engine gasket set from D&K, and OEM head gaskets from honda4u.com
- Brown grips, exhaust wrap, speedometer, clutch pull, and mufflers from Dime City Cycles
- K&N oil filters from Old Bike Barn

The little time I've had to spend with the bike in the last couple weeks has resulted in removing the swingarm (after I received the locknut removal tool), and rebuilding the forks:
Removing the twisted studs was easy using locked nuts for the top one and a pipe wrench on the bottom one, and heating before removal:
Metalworking hand tool Tool Metal Ranged weapon Gun

Since I didn't want to spend a ton of money on a special seal installation tool and waste more time waiting on delivery, I made this out of a spare PVC water pipe I found in a corner of my garage. It got the job done:
Machine Auto part Gear Machine tool Pipe

ps - The angle of this photo makes the bottom edge look a little ragged, but I made it flush with the top of the oil seal before tightening, so it didn't damage the seal. (this is also what I used to drive the bushing into place)

BTW, I've read a handful of threads discussing the availability of a good aftermarket swingarm lock-nut removal tool. Here's the one I bought and it fit and worked perfectly. Honda CX 500 CX 650 Swing Arm Socket Tool Swinging Arm Swingarm | eBay
No need to make my own, which seems like a pain well worth spending the $20 to avoid.
 

·
Registered
Joined
·
124 Posts
Discussion Starter · #12 ·
Finished out the rear suspension support, and got started de-tabbing the frame in preparation for powder coat!

Auto part Bumper Vehicle

Auto part


On the side, I've finished both fork rebuilds and started prepping the exterior of the engine. I want to have the whole exterior shined up and done before gasket replacements.
Looks a lot better when the corrosion comes off...

Metal Auto part Steel Engine Differential
 

·
Registered
Joined
·
124 Posts
Discussion Starter · #14 ·
Update:
The corrosion on the rest of the engine has been polished off and I'm ready to tear it down. However, I used a Dremel to grind off the corroded top layer of aluminum, but went down too far past the original finish to the point where it's now this awkward splotchy texture that looks like a bad spraypaint job. I intended to get it down to fresh shiny aluminum, but didn't know it would look this half-baked. Does anyone know a good way to restore a little of the natural dullness and uniform finish to the aluminum? Maybe a spray bottle of salt water, or even a highly diluted mix of concrete acid?

Here's a close-up of what it looks like now:
Auto part Metal Steel


I'm wondering if I let nature take its course on the bare metal, if it will go back to a relatively uniform finish, or if it will remain splotchy... Any metalworker guys out there care to weigh in?
 

·
Registered
Joined
·
124 Posts
Discussion Starter · #15 · (Edited)
Alright it's time to start tearing into the engine. Does anyone know a good *video* resource for opening and/or rebuilding a CX/GL500 engine? I have read a dozen threads and looked into the service manual and those resources are okay, but are all a little high-level for me - I'd prefer to find a turn-by-turn video of someone taking off the rear cover, removing/replacing the pistons, etc. One that shows what it should look like and how I should do it, because reading about it lacks the element of a real-life instructor showing & explaining, as well as a good deal of necessary low-level information.

Either that, or does anyone live in Southern Cal (Inland Empire) who loves teaching newbies, and wants to take a couple hours for something fun? ;)

I need to accomplish the following:
- Figure out why compression is low (120, 130)
- Figure out if the cam chain needs adjustment/replacing
- Replace the stator
- Adjust the valves

Bike shops sometimes do videos of tear-downs, which are a priceless tool to me as a visual learner. If someone knows of a resource like this for a CX/GL, I will send you a six-pack of beer.
Thanks,
--Carter
 

·
Registered
Joined
·
55 Posts
Love the monoshock set up! Exact same design I was thinking of doing to my CX500.
As for a video I will probably be making some videos of things I do to mine, though not sure yet how deep into this motor I will be diving yet.
 

·
Registered
Joined
·
24,568 Posts
i just fabbed a new rear frame section with the bump stop built in

but the real deal is the mono shock travel must be calculated so the tire travel and swingarm travle is within the safe scope

of the ujoint and driveline mine should never hit the bump stop the shock should limit it from hitting it unless something breaks





 

·
Registered
Joined
·
1,178 Posts
"Engine gasket set from D&K, and OEM head gaskets from honda4u.com"

Why is this? I have the same complete engine kit; am I to not use the head gaskets on my '82 GL?
 

·
Registered
Joined
·
124 Posts
Discussion Starter · #20 ·
"Engine gasket set from D&K, and OEM head gaskets from honda4u.com"

Why is this? I have the same complete engine kit; am I to not use the head gaskets on my '82 GL?
I've been told by a number of people on here that the "paper" gaskets that came with that set (or any non-OEM gasket set) will eventually leak, and it's better to use the OEM ones. I just followed that advice, as it came from experience and I hate rework.
 
1 - 20 of 86 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top