Rebuilding the CT90 that went to the top of Alaska

Dec 03, 2021

“Get me to the Point, and I’ll give you a full rebuild when we get home.”

The combined plea/promise tumbled out of my mouth as the CT90 sputtered and struggled in the sand near Point Barrow, just a mile from the northernmost point in Alaska. The little 46-year-old Honda and I had been through a lot in the previous 1,000 miles, and now I was asking it to work harder than ever, all while getting doused in seawater.

Ari Henning and the CT90 on the Haul Road in Alaska. — As riders, we develop relationships with our bikes based on what we’ve experienced together. Needless to say, I feel pretty close to this little CT90. Photo by Zack Courts.

We made it though, and once the bike was nursed off the Point, flown back to Anchorage, and shipped back to Los Angeles, it was time to make good on my pledge. Over the course of roughly five days, I wrenched on the CT90 while Spenser documented the project in a soothing, sound-forward format. No speaking, no music. Just methodical mechanical processes and the natural sounds that accompany them. Spenser was meticulous with his camera angles and lighting, while I just did what I love to do: Work quietly in the shop on a splendid piece of engineering.

The video below is the result of our combined efforts, as well as the painstaking editing of RevZilla West’s own Stephen Gregory.

1975 Honda CT90 Rebuild, ASMR Special | The Shop Manual

It’s important to note that this was a rebuild, not a restoration. We fixed what needed mending and replaced truly worn components, but I was as prudent with new parts as the CT90 is with gasoline.

Honda made tens of millions of these motorcycles, so it’s the story the scuffs and scars tell that makes this particular machine special. The paint was worn off by my boots with help from Dalton Highway dirt, and the rust on the cast-iron cylinder is from the Arctic Ocean, for cryin’ out loud. Painting the frame and soda blasting the cases would have been sacrilege.

Worn out piston from the 1975 CT90. — This piston gave all it had to give. It’s chafed, scuffed, and discolored from a lack of lubrication and extreme hot running, but it kept doing its job. Amazing to think that a little two-inch slug is all it takes to get you anywhere you want to go. Photo by Ari Henning.

The bike had clearly lived a hard life, even before I put it through hell. It needed a new piston and rings, and the steering head bearings were some of the driest, most brinnelled I’ve come across. And the sludge that spurted out of the fork — easily the most fetid fluid to ever come out of a motorcycle.

Other than that, it was just normal maintenance and lubrication, because Soichiro did all the hard work decades before I was born.