1959 - Herb Uhl Trail Super Cub The CT90 traces its origins to Herb Uhl, a motorcycle dealer in Boise, Idaho, who modified the newly imported Honda Super Cub to increase its appeal to his customers, many of whom wanted a cheap and robust motorcycle to get about in the surrounding hills.
American Honda Motor Company was established in California in 1959. You can see a Super Cub poking out the back of the pickup truck on the right
His initial modifications involved removing the bulky leg-shield, adding a 82-tooth overlay sprocket to help with hill climbing, and fitting a custom 'peashooter' exhaust to improve ground clearance.
left / centre - some of the earliest modified Super Cubs sold by Herb Utl / right - the man himself with a later version which included knobbly tyres (the front mudguard was removed to better accommodate the larger tyre). Photos from the Herb Utl collection
These modified bikes were based on the very first Super Cub - the 1958 50cc C100. This was launched in the US in 1959, where it was known as the CA100 to distinguish it from the Japanese domestic market version that had a single seat and came with turn signals.
The super cub was an instant success - and very cool. Honda USA dropped the Super Cub branding in the early 1960s, using the 'Honda 50' monicker instead, therefore avoiding a row with Triumph whose (Tiger) Cubs were already popular in the UK and US.
You can hear Herb describe his involvement in creating the legendary CT90 in this video
1961 - The first Trail 50 (CA100T) By 1960 Honda America had got wind of the surprisingly high volume of Super Cubs being sold out of Herb's shop and asked him to send one of the modified trial bikes to California. Honda USA duly sent this on to Japan with a request to build a production version and, by March 1961, Honda's new Trail 50 was offered to Honda dealers across America. This initial release was a pretty faithful copy of Herb's original changes and was an immediate success.
Honda's first production Trial bike - 5 horsepower with three-speeds and automatic clutch. Like Uht's custom version, it came with knobby tires; the original Honda 50’s leg shield and front fender were removed for better off-road utility and a double rear sprocket permitted changes to the overall gearing. A large chrome rack was added and a skid plate to protect the engine were available as optional extras.
The model went through a number of revisions, eventually becoming the popular CT brand. These changes are described below.
1962 - Trail 55 (CA105T) 1962 saw the introduction of a slightly larger (55cc) engine to the Honda 50/Trail range. The Trail 55 also got a larger gas tank and the addition of a hand operated rear brake lever on the left hand handlebar (handy when paddling down hill). The carrier rack was now fitted as standard.
You can read Cycle World's approving review below.
Honda 55 | Cycle World | NOVEMBER 1962
Cycle World Contributors
1963 - Trail 55 mark II In 1963, an upward-tilted muffler was fitted to improve clearance and to allow the bike to pass through shallow water.
1964 - Trail 90 (CT200) A major upgrade came in 1964 when Honda fitted their new 87cc overhead valve (push rod) engine and incorporated the same 4-speed gearbox used in the C200 Benly.
the first Trail 90 - 30% more power and 4 speed gears
This model also got a more robust skid plate to protect the engine and was the first model to be fitted with a Krizman spark arrestor .
1966 - CT90 K0 (early) In 1966, Honda unveiled their newly designed 89cc overhead cam engine - this was fitted to a number of models, including the CL90, C90 (Super Cub) and S90 and a slightly detuned version was fitted to the Trail 90, which from this point forward was christened the CT90.
This engine, with one notable modification - the addition of a sub transmission (described below) - was used until the end of production in 1979. The 1966 bike is the first model to follow Honda's K series numbering convention, which went as follows:
Model number From frame number Years CT90 K0 100001 1966-68 CT90 K1 200001 1969 CT90 K2 300001 1970 CT90 K3 400001 1971 CT90 K4 1400001 1972-73 CT90 K5 1500003 1974 CT90 K6 1600003 1975 CT90 K7 1700004 1976 CT90 K8 1800008 1977 CT90 '78 1900010 1978 CT90 '79 5000011 1979
1967 - CT90 KO (late) 1967 saw the introduction of an important innovation, the new posi-torque sub-transmission that replaced the Trail 90’s double sprockets. This brilliant invention allowed riders to switch between low and high gear ranges with the flip of a lever, rather than faffing around with chain links and sprockets.
1969 - CT90 K1 A major update was made in 1969 - the new model included a number of improvements and saw the first significant departures from the bike's Super Cub heritage.
Firstly the incorporation of telescopic forks, which increased the travel of the suspension over the original leading link forks . The air filter arrangement was also remodelled, moving the unsightly and testicle-endangering airbox from the down tube to the right hand side. This new design aimed to balance the cleaner lines of the bike keeping whilst keeping air intake high enough to reduce the risk of water getting drawn into the engine. There were improvements to the carburettor too - the new model included a high altitude adjustment knob for use above 6000ft: something of a curiosity for those of us in the UK - whose highest mountain is significantly lower than 6000ft - but a genuine boon for the millions of folk in the US who either live at this elevation or regularly travel there. New handlebar lock Foldable passenger foot rests Later in 1969, the bikes came with a wider 3'' front tire, which became standard for the remainder of the models. It is worth noting a couple of other unique features on the K1:
This model has a one-year-only headlight bucket, fork-ears and speedometer design (borrowed from the S90 range of the same time) The early run of bikes came with a one-time carb design - recognisable by the 4 screws holding on the float bowl and offset inlet pipe mounts. You can read more about the various carbs used on the CT90s here . Engine updates
The intake port in the K1 cylinder head was increased to 20mm (18mm on the K0) and the old pinion style kick starter was replaced with a new design , resolving a common issue where the ratchet could over-rotate and cause serious engine damage. The K1 also came with the first of several attempts by Honda to improve the cam chain tensioner.
The bikes came in Scarlet Red or Yellow.
To mark the new design Honda restarted the serial numbers stamped on the engine and frame at zero, hence the references to Frame No. 000001A on the parts and wiring diagrams for the K1 models. In practice, from this point forwards, Honda prefixed the serial number with a single digit number indicating the year of manufacture, starting with the 200000 range for the K1, 300000 for K2 and 400000 for the K3.
1970 - CT90 K2 There were several changes in the following year:
a larger headlight (now a sealed-beam unit), redesigned speedometer, new foldable swivel-lock handlebars, and redesigned muffler guard. Body colours remained unchanged, but the side panel was now grey. The air cleaner intake was moved from the side of the frame and now connects to the underside of the carrier rack - a rather less aesthetically pleasing arrangement, but one that raises the intake a few more inches above any potential water ingress. The exhaust heat shields were updated so the exhaust pipe cover now extends to below the engine One final tweak was the replacement of the front brake light actuator which - on the K1 - involved an unwieldily mechanical switch spliced into the brake cable - with a simpler spring loaded mechanism that is fitted in the lever mount. The bikes were Scarlett Red or Bright Yellow.
1971 - CT90 K3 The chrome muffler coating was changed to a heat-resistant matt black, and a vertical black bar was added to the grey plastic frame tube shroud. The colours are Scarlet Red or Summer Yellow.
1972/73 - CT90 K4 Now available in distinctive Mars Orange.
mars orange (left) / new speedo design (note the "W" for winkers)
The newer seat and tank design , recognisable by the chrome rivets, allows a wider and better upholstered seat at the expense of a little tank fuel capacity (now down to 1.5 gallons). The auxiliary fuel tank (shown above), became standard equipment on the left side of the rear carrier. Larger rear light trip odometer added to the speedo and the max speed stops at a more realistic 60mph. the '73 version came with a black plastic cover over the clutch adjustment nut in the right hand engine case. As a result of the introduction of the kill switch, there are two versions of the wiring harness:
1969-73 (K1-K4) 1974 onwards (K5 and later) The two version are easily distinguishable by the number of connections in the section of the harness terminating in the headlight bucket (the earlier version has 10 connections and the later has 12).
Turn signals were still available as an optional extra, although these would become standard the following year:
1974 - CT90 K5 A few changes on the electrics
new kill switch introduced new silicon rectifier (replacing the old orange-finned selenium version) turn signals become standard equipmentA couple of tweaks to the speedo - the highbeam indicator is now blue, rather than red, and winkers are labelled 'T' (turn signal) rather than 'W'.
So that the rear turn signals and auxiliary tank could be used together, Honda had to move the rear indicator mount from the rear mudguard/fender to a rather more precarious position on the rear light/registration plate bracket. Still in Mars Orange.
As a result of the introduction of a kill switch in 1974, there are two versions of the wiring harness:
The two version are easily distinguishable by the number of connections in the section of the harness terminating in the headlight bucket (the earlier version has 10 connections and the later has 12).
The 1974 also got a redesigned cylinder + cylinder head:
Cycle WorldContributors
Comments
Nothing yet. Say the first thing.
Sign in to join the conversation.