The Honda CT 110 is a small motorcycle manufactured from 1980 and on. It’s essentially the CT 90 of the 1970s but with a slightly enlarged engine. In 1980, Honda increased the displacement by 16 cc, or 18%, over its CT 90 ancestor. The transmission is a four-speed with automatic clutch. It has the modern telescoping front fork suspension, introduced with the 1969 Honda 90. Strangely, Honda dropped the second gearbox, or subtranny, and convenient “high–low” lever switch in its 1980 model, only to restore them in 1981 and onward.
My particular Honda CT 110, serial number 5,006,649, dates to 1980. It’s powered by the original one-cylinder, four-stroke, air-cooled, 105-cc engine. Sadly, it lacks the subtranny, being a 1980 model.
It incorporates many changes developed on the basic CT 90 layout through the 1970s. Compared to systems on my 1968 CT 90, the breathing system begins farther back, the instrument gauge cluster is redesigned, and there are turn signals, actuated by a switch on the right-side handlebar. The fuel tank, seat, and fenders differ geometrically. A side kickstand takes the place of a center stand. There’s a molded cosmetic plastic unit covering the main frame member. The headlamp and tail-lamp differ cosmetically from those of my 1968 CT 90. The handlebars can pivot, or “fold” in a way, for more compact storage.
Notice the strange little black reserve fuel container hanging on the rear. It’s the original and is much prized by collectors of these bikes.
I got my 110 from the same brother-in-law who had gifted me my CT 90 a few years earlier. The 110 was functional upon receipt. The deal was that in exchange I would repair the electrical system in his (another) Honda 90, which I did. This 110 has a luggage rack (optional accessory). It also came with the original owner’s manual(!).
Deferred maintenance. I completely disassembled the carburetor, cleaned out various gum and other (aluminum oxide?) deposits, and reassembled. The bike got a fresh battery. It needed little else to restore it to more-or-less original condition. I probably replaced a tire and a light bulb or two. If I recall, I may have cleaned out the brake drums and cleaned and lubricated the chain. Naturally, I gave various parts of the bike derusting, degreasing, lubrication, and general cleaning treatments.
Upgrade. The Honda 90 had shown how it could get us way close to superabundant High-Sierra trout fishing on old logging roads and other sketchy one-lane roads. I wondered whether the Honda 110 could do the same. It has a bit more power than the 90, but it lacks the 90’s low-range transmission setting. It occurred to me to install a larger rear sprocket for enhanced hill climbing.
This was done by obtaining an old CT 200 wheel, from Ebay. No large sprockets were on the market at the time, but a complete wheel was (rotted, rusty, bent spokes, who cares), incorporating the odd, large, rear sprocket of the CT200. Naturally, everything but the target part was discarded, and the desired sprocket was installed on the CT 110. It went on with nuts and bolts beside the existing rear sprocket. There it is in the photo above. Effective tooth count went from 45 on the existing sprocket to 68 on the modification. Theoretically, the bike’s hill-climbing ability is increased by 51%.
Naturally, the chain received additional links to accommodate the larger sprocket. The chain guard needed to be removed, as shown.
Useage. I’ve driven the 110 comparatively little since I acquired it around 2005. It’s given me a few joy rides around the neighborhood. It’s amazing the emotional lift one gets from doing a few loops around local blocks at 20 mph on just a little Honda 90 or 110.
Finally, to test how the big rear sprocket would perform, I put the 110 to use on a wilderness fly-fishing excursion. This was in June 2016, and I assumed the old mining roads in the Sierra would be muddy and covered with snow patches. I was correct, and our van was unable to get up to the edge of the wilderness (our Isuzu Trooper maybe, just maybe, could have made it, but why risk it?). The 110 did the last few miles up a steep, nondescript dirt (muddy, snow-covered) road, thereby saving me a 1,000-ft elevation gain with a fully loaded backpack.
Here’s the bike (below) parked near the end of the road beside a meadow at almost 9,000 ft of elevation.
From there, I hiked cross country to this tiny, seldom-visited lake, …
… where I easily caught these tiny specimens from among the abundant stunted brook trout overpopulating the water.
I then moved on to this lake, …
… where I landed this respectable, tasty brook trout
So that, my friends, is the sort of place where an old Honda trail bike can take you.
Shifter break and repair, 2021-22. In late 2021, three of us rode from San Jose to The Junction on State Route 130. On Mt. Hamilton, the 110, which I was riding, after a few hard shifts, refused to leave 4th gear. We made it to The Junction and back, but it was a difficult ride. The problem, I later learned, was caused by a broken shifter drum (photo below).
And the break was caused by a loose holder plate. This plate (not shown) is a star-shaped piece that bolts to the drum where my thumb is in the photo. The star plate serves two functions: it holds four pins (not shown) that go through the holes and that the shifter level grabs onto, and it stops the drum rotation beyond neutral and 4th. The bolt had unthreaded itself, the star plate and pins came loose, and shifter force on the cockeyed pins broke away the piece of drum. An exhaustive online search for a replacement drum yielded absolutely nothing.
In mid-2022, I fabricated the missing piece, welded it in, and reassembled the drum. Before completely reassembling the engine, in place of the original Phillips-head bolt holding down the star plate (crummy design), I substituted a hex-head bolt and split washer, and I gave them about 35 ft-lbs of torque: way better. A test ride gave smooth shifting through all the gears.