With the last of the wiring finished and an unscheduled rebuild of the brake master cylinder completed, our long-term project bike—a forlorn 1975 Honda CB550—was finally ready for its first test ride. Four anxious dudes hovered around the open garage door as the Honda crackled to life and drove out into the sunshine under its own power for the first time since 1983.
If you’ve ever undertaken such a project, you probably know the hurdles your brain goes through for those first few miles. Are all the bolts tight? Did I press the wheel bearings correctly? Is this thing going to fall apart and end me? It’s a mental rollercoaster, but eventually, confidence is inspired, and you crack the throttle a little further to get a feel for what you’ve created.
I strafed the streets by our shop a dozen times, pushing the little four-cylinder more with each pass. It sings at high rpm, and the exhaust crackles on deceleration. The brakes are spot on, and it feels like we’ve done a righteous thing by breathing new life into this old machine after 42 years of sitting.
With a shit-eating grin on my face, I went for one last full-speed run past our shop before I’d let the neighborhood return to its summer afternoon quietude. And that’s about when the cops showed up.
Wiring a Custom Motorcycle—The Final Boss
I know there are some weird dudes out there who thrive in the fussy world of wiring—I am not one of those dudes. I avoid it like the plague, and if you want real advice on this topic, I’d direct you to our Motorcycle Wiring 101 guide. Thankfully, we have friends in high places who set us up for success, as Motogadget sent over a full suite of their universal motorcycle electrics.
When you start taking apart a motorcycle, one of the things I guarantee you’ll want to simplify is the wiring. There are harnesses, subharnesses, modules, relays and more, and you’ll be asking yourself how much of this can go straight to the dumpster. Thanks to the power of the Motogadget mo.unit blue, the only stock items we reused were the points, coils, regulator and rectifier.
In broad strokes, the mo.unit blue serves as the new nerve center for your motorcycle, with 12 inputs and 10 outputs that cover most of the functions of your electrical system. The mo.unit takes the place of your relays and more, and your old fuse box can go straight to the trash since the device monitors all circuits and shuts them down in the event of a fault. Measuring 3.5” x 2,” the mo.unit blue is compact and easy to find space for. Since we were short on space under the seat, we fabricated an aluminum box that fits behind our front number plate.
While the mo.unit is the heart of the operation, Motogadget hooked us up with other items that simplified the wiring process. We used a pair of mo.switch basic buttons to start the bike, operate the mo.blaze tens indicators and turn the lights on and off. We used 12 AWG for the battery +12 V feed, main ground and the starter circuit, while 18 AWG is sufficient for most switched output circuits. Low-current switch outputs use super slim 22 AWG. For this project, we based the majority of our system on a handy wiring diagram courtesy of Revival Cycles.
Remaining Odds and Ends
With our new electrical system sorted, it was time to turn our attention to some of our Honda’s other mechanical needs. It was in dire need of an oil change, which should be no sweat, except that the CB550’s oil filter housing bolt has a tendency to lock up tighter than the bossman’s wallet. We rectified the issue by welding a larger nut in place of the tiny 14 mm bolt head so it won’t be an issue in the future. Then we turned our attention to the carburetors.
The CB550 uses a bank of Keihin 022A constant-velocity carburetors, and ours were a total mess. Three of the four jet retainers were missing, fuel in the bowls had turned into tar and someone had broken one of the float towers off decades ago. Their JB Weld repair held up about as well as a white zip tie in direct sunlight, and there was no correcting the damage, so we went on the hunt for a better set.
eBay and all the typical sources were well outside the budget, so we called on our friend Ken at Cycle X in nearby Hazelhurst, Wisconsin. In addition to giving us a killer deal on the CB years back, he’s a wealth of information and pointed us towards a semi trailer out back where we’d find what we were after. You can’t put a price on knowing the right people, and between the two sets, we ended up with a smooth-running rack of Kehins.
With the carbs sorted, the Honda’s 544 cc SOHC four fired off like it had just been parked. It was as if four decades of sitting meant nothing to this little engine, and there wasn’t even any valvetrain noise to speak of. It’s impossible to overstate the longevity of these ’70s Honda four-cylinders, and if you’re thinking of dipping your toes into the world of classic motorcycles, you need to start with one of these.
But that’s not to say that this machine was completely ready to be pressed back into service. The front brake master cylinder hadn’t taken kindly to decades without fluid, and after we bled it for the first time, it puked its guts all over the lift table. Thankfully, a rebuild kit from Common Motor Collective was super affordable and got our brake braking again. The larger issue we’d encountered was engine oil, as our CB was hemorrhaging from somewhere behind the sprocket cover. The countershaft oil seal proved to be the culprit, but we also replaced the shift shaft seal while we were in there.
With some minor fettling and adjustments, our CB was ready to take flight, and unless you skipped ahead to this part, you know that ended with a visit from our local PD. Thankfully, they understood our program and were able to look past the exhaust and ’83 Illinois plates—gotta love living in a small town.
Okay, So What’s it Ride Like?
Out of all the old jalopies I’ve ever ridden, I can’t say a CB550 is one of them, so I had very little frame of reference for this machine. I can tell you that it’s a Honda through and through, and even though we never tore into this engine, it fires up and runs beautifully. While it’s only rated at 50 hp new, the 550 gets up to speed quickly, and it probably helps that we sliced serious curb weight off this machine with the removal of the center stand, fenders, factory lighting and other superfluous road-going equipment.
The engine slumbers until you get the rotating assembly singing, and peak power doesn’t hit until 8,500 rpm. Keep the needle up and you’re rewarded with a surge of mid-range power and a sublime experience from corner to corner. The braking is what you’d expect from a Honda from 1975, but the cornering is quite good after we lowered and stiffened the front end, in addition to cranking some extra preload in the rear shocks. For all the flak we received for the Bridgestone Battlax AX41 tires, they provide substantial cornering confidence for a 40/60 tire.
And on that note, we clearly had dirty intentions with this bike from the get-go, and it doesn’t disappoint. It probably weighs around 400 pounds the way she’s dressed, and it doesn’t take any serious effort to get her sliding. That’s when the wide handlebars and Tuffside tracker seat shine, and while I’m no flat tracker myself, this machine certainly brings out my inner Mert Lawwill.
While it doesn’t really have the suspension travel for serious off-roading, it’s a killer machine for tearing down back roads, getting tail-happy on the gravel fire lanes and getting you back home after a day of hooning. It’s still a perfectly practical motorcycle for daily use, but it’s more than happy to bomb corners and get down in the dirt as well.
What’s Next for the Honda?
If you’ve ever owned anything old, you know that a project is never truly finished, but our Honda is now to the point where it does all the things it should again—and some things it was never intended to in the first place. The goal here was never perfection, and if you look closely, there’s room for improvement. The engine cases could be vapor blasted, the paint is far from show quality and there are plenty of nuts and bolts on this machine that are obviously original.
Rome wasn’t built in a day, and neither was the motorcycle that’s on your screen. I won’t claim that we moved mountains here, but over the last two years, we’ve brought you nine installments on this build, covering the nitty-gritty jobs like re-lacing wheels and mounting tires, to rebuilding suspension and fabricating parts. You’ve seen every step along the way that took this bike from a $400 derelict to a fun-loving hoonmobile, and we did it all the shade-tree way. All said and done, we’re talking about a bike that anyone could build for an investment of around $3,000.
If we’ve accomplished one thing here, my hope is that this motorcycle has inspired one person to go take some rusting piece of history and breathe some life back into it. Bikes like this $400 Honda can be found stashed away in every corner of the world, and they’re begging for a new lease on life. That said, we’ve done everything we set out to do with this bike, and we can’t keep them all. By the time you read these words, our Honda CB550 tracker project will be live on the Bike EXIF Auctions, where you can bid for your chance to write the next chapter in this motorcycle’s story. Offered at no reserve, it will be sold to the highest bidder.
So I suppose that marks the end of our CB550 street tracker build, and whether you loved it or hated it, I hope you learned something along the way. If you enjoyed seeing this motorcycle brought back to life, stick around, because we already have the next one on the chopping block for an even wilder transformation.
