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Discussion Starter · #1 ·
This thread is long overdue. First off, I need give a huge shout out to all of you on this forum. Without the collective wisdom of those here, my build would not have been possible. A little about me...I live in Ottawa Canada, and have been a shade tree mechanic all my life. My primary passions have been large keelboat sailing, and wrenching on vintage British sports cars. In the last few years I've started to build/rebuild motorcycles as well. I started out by chopping the heck out of a 1998 Honda Shadow VT750 and turning it into a bobber. Then, I decided that my wife and little dog might enjoy a sidecar rig, so I added a heavily customized sidecar to the bobber. I've been working on my CX500 build on and off for about 15 months. It came to me literally in pieces (and many pieces of the jigsaw were missing). I paid a whopping $500 CDN dollars for everything that was to be my starting point. The costs ballooned from there...more on this later. I know many of you are incredibly disciplined about updating your build thread as you go through the build. I'm simply not that organized, and frankly would rather spend my time wrenching, than being on a computer updating a forum thread. That said I did take plenty of photos along the way, and always intended to write up this build at a later date.....so let's begin. first images are of my only previous build the Honda Shadow VT750 bobber plus sidecar.
Before:
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After:
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Out for a ride with my buddy:
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I heavily customized a production Sidecar rig and mated it to the bobber for a time:
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This was my new-to-me 1980 CX500 as purchased:
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And the "Piece De Resistance" a new set of Murrays Carbs included. These alone were worth the purchase price of $500:
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END PART 1
 

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Discussion Starter · #2 ·
PART 2 FRAME CHOP AND WELD
So even before I could begin considering my design ideas, I had to do an inventory and figure out which parts I had, which parts might be surplus, and which parts I would have to either fabricate or purchase. I was fortunate to find a seller in Montreal who was selling a large stash of CX500/GL500 parts for a very fair price. This helped fill in some of the voids.

I'm sure that almost every builder who has contemplated a CX500 rebuild design, is confronted with the unusual rear subframe shape of the CX500. I gave much thought to how to integrate the unique curves of the stock frame, but in the end I just couldn't realize the vision in my head while still keeping the subframe intact. So out came the grinder and cut off wheel
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I haven't the facilities to bend thick wall steel tubing, so I gave my design to a local metal shop and they bent this hoop up for me
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After a little more chopping and welding I ended up with what would be my new frame:
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The gussets where the salvaged upper shock mounting pivots are welded into are 3/8" thick and angled perfectly to maintain the rear shock geometry. The aftermarket rear shocks in these pics are just for mock up, and are replaced later in the build.
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END PART 2
 

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Discussion Starter · #3 · (Edited by Moderator)
PART 3 The 22 Degree twisted twin engine rebuild

I'm not going to go into too much detail on the engine rebuild process as it has been more than amply documented elsewhere on this forum. Suffice to say I installed new rings, main bearings, mechanical water pump seal, and all new rubber seals and new gaskets through out. All engine parts were painted semi-gloss black, and the clutch cover was hand polished and then carefully hand painted in with black around the Honda logo. Cylinder head gaskets are not the ones which came with the aftermarket gasket kits, but wee replaced by NOS Honda OEM head gaskets which were first sprayed with Permatex copper high temp sealant as recommended by many trusted engine builders on this forum. All intake and exhaust valves were hand lapped into the cylinder heads.

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Perhaps the eagle eyed among you will have noticed that the front of the camshaft stub has been cut and ground down to make room for the electric fan conversion which can been seen on the radiator. This conversion is fairly common and again well documented on this forum. The only place I may have deviated from convention, is by welding a threaded bung on the rigid coolant tube where I installed the temperature switch to activate and shut of the electric fan.
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END PART 3
 

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Discussion Starter · #4 ·
PART 4 Paying Homage to the Norton Manx .... (Honda purists please look away)

So I call my build the CX500 "Manx". I decided early on that I wanted my CX500 to exhibit styling queues from the glory days of Norton's racing pedigree. The Norton Manx was built in Britain starting in 1947, and they were raced and campaigned successfully until model production ended in 1962. I've always had an almost visceral reaction to pictures or film footage of these vintage racing machines. Given that my build was beginning with just a pile of parts, I felt I had a blank slate. So I elected to try to incorporate details in my design that would pay homage to these wonderful powerful works of art.

The polished aluminum tank I chose was handcrafted offshore, and was originally intended to be installed on a CB750 framed café racer. This posed some issues for me, as while the tank was the correct overall size, the unique CX500 frame arch, and engine hanger mounts created significant clearance problems on the underside of the tank. This was ultimately resolved by some minor "surgery" as shown below.

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The seat pan and hump was handcrafted by a skilled artisan in Texas. It will be the starting point for a custom seat.
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The last component of the Manx body work is a matching polished aluminum front fairing which I sourced from the fine craftsmen Markus Pintzinger of Omega Racers.
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END PART 4
 

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Discussion Starter · #5 ·
PART 5 Bye Bye Comstars

Unlike some folks, I really don't hate the Honda Comstar wheels. While I expect I will use the Comstar wheels on my next CX500 Build, I really didn't think they suited this bike. I instead elected to do a Comstar to spoke wheel conversion.
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The rear wheel was originally installed on a Kawasaki Z1. I re-laced it to the chopped up rear CX500 drive hub onto which I installed the adapter rings from Cafe Racer kits in the UK. The front rim was off a Norton Commando ..Again I re-laced it to the stock Honda front hub using spokes custom made by Buchanan Spokes just like the rear wheel. Overall I'm very pleased with the new look... I think it suits the bike much better.
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Discussion Starter · #6 ·
PART 6 Seat Construction

I laid up a fiberglass cushion support with integral steel brackets. Added a custom seat cushion to fit both the fiberglass support as well as the seat pan out of high density foam. I hinged the seat to the pan all down one side with a stainless steel piano hinge. I then configured a cylinder lock and latch mechanism which securely holds the seat pan down. The key is entered from below the seat and the lock is not visible unless looking up under the seat from the ground. The seat pan itself is fastened to the frame with 4 button head machine screws tapped into the frame support members. I considered trying my hand with my wife's sewing machine to sew up the cover, but ultimately elected to bring the seat to a local upholsterer. I had worked too hard to have the cover come out looking like something i whipped up in my garage.
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Discussion Starter · #7 ·
PART 7 Under Seat Electrics Tray
I've seen a number of other CX500 builds which utilize a relocation battery box which hangs under the engine where the original exhaust H box was located. I think this is really ingenious, but was concerned that the box under the engine solution might detract from the overall lines of this build. So I started looking at ways to have all electronics completely hidden out of sight. Fortunately for me, there was ample space available under the seat hump where I could locate the Shorai lithium battery. I made an electrics tray out of sheet metal which tucks up discretely between the top frame members. Due to the decision to use the Shorai battery, it was necessary to purchase a proper Shindengen FH020AA MOSFET regulator/rectifier. I was concerned there might be insufficient airflow under the seat, so instead mounted the rec/reg unit up underneath the seat hump above the rear wheel.
The Motogadget M-Unit Bluetooth was stupid expensive, but I had to have it. It sure helps with ease of wiring and and uses very little space in the tray. It also allowed me to use different handlebar switching (more on this in future chapter).

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