Follow Along As I Start My 1978 Honda CX500 Cafe Racer Motorcycle Build

Posted by Dan Doyle on 25th Aug 2015

So, I just picked up a vintage Honda 1978 CX500 motorcycle a few weeks ago and I plan on doing a, get this... Cafe/Brat build! I know, I know, “You're breaking some new grounds there, Copernicus.” Hey it’s been done, but then again, so has just about every bike. I’m gonna find a way to make it my own and HOPEFULLY stand out from the crowd. It's my first bike/build so I'm at least gonna chalk the whole thing up to a learning experience more than anything.

First thing's first... Get it running right so I don’t get stranded during our trek to the Adirondacks in late September. Easy enough.

After driving it a bit, two things became very obvious. The carbs need work and the valves desperately need to be adjusted.

Since I plan on rebuilding the carbs, I might as well up the jets from 78/112's to some larger 90/120's to compensate for the K&N pods and exhaust that I plan on using. There's no sense in getting the thing running right, just to tear into the carbs again so I ordered the pods and exhaust right away, but more on that later…

Before I started tearing apart the carbs I did some research and decided to get Larry’s book on rebuilding the Honda CX/GL500 carbs. Let me just say that this guy is THOROUGH. He covers everything you need to know about these carbs. Tear down, ultrasonic cleaning, standard (Non-ultrasonic) cleaning (A fool’s errand!), pulling all of the jets/emulsion tubes, repairing damaged parts and finally syncing the carbs. Probably a hell of a lot more, but I can’t remember off the top of my head. Basically, If you’re thinking about rebuilding your CX500/GL500 carbs, get the book. Here’s a link http://www.donlhamon.com/carbbook.html

Once we took them apart, we noticed they were dirty, but nothing alarming.

So I bought the Ultrasonic cleaner at Harbor Frieght for $79 per Larry’s recommendation. I was skeptical at first, but holy shit does this thing work! Get the larger 2.5 liter unit that’s heated and use about 10 ounces of Simple Green HD (The purple stuff) and fill the rest with water. The carburetors aren’t going to be completely submerged so do several 480 second intervals on each side of the carb. I recommend turning the carb anyway to ensure that you get fluid in all of the passages. Make sure to change the solution when it gets dirty or else you run the risk of staining your carbs.

I had to “easy out” the press-in low jets and unfortunately an emulsion tube after my failed attempt to remove it with a “custom” flat head screw driver even after I sonic-cleaned the damn thing several times AND let it soak with PB Blaster for two days. I guess that’s what thirty plus years of use will do to a carburetor.

While I was cleaning my carbs and flipping them every 8 minutes for what seemed like an eternity, I decided to get started on painting the exhaust…

At first I planned on going with the chrome Mac 2 into 1 exhaust, but of course changed my mind (As I always do) days after I received the exhaust and decided to go with a black exhaust, wrapped in Titanium heat wrap with a glasspack and some other custom touches that I’ll get into later on. “But, Dan. Why didn’t you just return it and swap it out for a black exhaust?” How about, shut up! Plus, I didn’t really feel like waiting. I’m impatient.

Here's most of the exhaust right out of the box (minus the Mac muffler that I’ll end up selling and the 45 that I plan on using to install the glasspack in a different location later on.)

Mac 2 into 1 Exhaust (chrome for now)

Cherry Bomb Glasspack

DEI Titanium Exhaust Wrap (Won't discolor and I like the look of it over the black)

First I sanded everything down… (I kinda like the “Rat Rod” look of the red on the Cherrybomb after sanding it.)

Then applied several coats of VHT Hi Temp Primer…

Then VHT Hi Temp Paint Black…

Thennnnnn I researched what to do about the dried up passage plugs, ripped crossover tube o-rings, destroyed emulsion tube and low jets that had a star pattern pressed into them after using the easy-out. That took a couple of sleepless nights, but I actually figured out all of the part numbers and put together a plan of action. It was going to cost a bit and take some time before I was gonna be able to put the carbs back together, but I figured, if you’re gonna do something. Do it right. I’m impatient, not stupid.

…Then Larry called me the next day after another failed attempt at calling a Honda dealer to special order the parts. He told me that he’s got everything I need and that he could get all the parts to me within a couple of days. Boom! Larry saves the day. Classic Larry… You’re a God damn hero, man! Just wish he had called back a day earlier. Coulda got some sleep last night instead of researching the correct part numbers while watching the flop of a movie that is “Chappie,” but I digress.

So while I wait, I’m gonna tear some more shit off the bike, install the exhaust, change the plugs and adjust the valves.