The earliest CT90s shared the same leading link suspension as the C90 Super Cubs. This is a great design, offering a comfortable ride and minimising maintenance issues by tucking the moving parts away from the elements. However, the forks were designed for road use and therefore only allowed a small amount of suspension travel; not...
The earliest CT90s shared the same leading link suspension as the C90 Super Cubs. This is a great design, offering a comfortable ride and minimising...
Honda CT90
I have just finished recommissioning a 1969 CT90 K1. The bike was originally sold in the US and was imported to the UK from California a few years ago.
One of the many repairs that needed doing was to replace the damaged wiring harness, so I colourised the wiring diagram to help with the job....
I have just finished recommissioning a 1969 CT90 K1. The bike was originally sold in the US and was imported to the UK from California...
Honda CT90
There are plenty of places that will rebuild your crankshaft for you, but it is also a job that can be done at home if you have the right equipment.
tools
You'll need a press (minimum 10 ton) to remove the pin and to reassemble the crankshaft and you’ll also need some...
There are plenty of places that will rebuild your crankshaft for you, but it is also a job that can be done at home if...
C90 Engine
Intro
If you have dismantled your bike in order to refurbish it then, once you have finished reassembling the engine, you will be faced with a large pile of bits that need putting back together. In the immortal words of the old Honda manuals:
"Perform the reassembly in the reverse procedure of disassembly."...
Intro
If you have dismantled your bike in order to refurbish it then, once you have finished reassembling the engine, you will be faced with...
C90 Engine
It hardly needs saying but the engine only works when air gets in one end and exhaust gasses exit the other. This article covers the two systems on either end of the engine, the air cleaner and the exhaust.
Muffler and exhaust pipe
Although in the UK we tend to refer generically to "exhaust...
It hardly needs saying but the engine only works when air gets in one end and exhaust gasses exit the other. This article covers the...
C90 Engine
The forces created by combustion pressure are transferred to the piston through to the connecting rod, causing the crankshaft to turn and thus converting the reciprocating motion of the piston to rotary motion. Here's what I learned about how it works.
construction
The connecting rod is located on the crankpin and the webs[...
The forces created by combustion pressure are transferred to the piston through to the connecting rod, causing the crankshaft to turn and thus converting the...
C90 Engine
The transmission takes energy from combustion and transmits it to the rear wheel. The mechanism is shown below:
The power is transmitted through a fairly convoluted path before it reaches the rear wheel: energy created by combustion forces the piston downwards causing the crank to rotate. The crank rotation is then transmitted through the clutch...
The transmission takes energy from combustion and transmits it to the rear wheel. The mechanism is shown below:
The power is transmitted through a fairly...
C90 Engine
The c90 uses a drum brake design that is essentially unchanged since it was first introduced over 120 years ago.
Renault drum brake
Drum brakes were first patented by Louis Renault in 1902 (see the patent diagram below left). Despite its apparent simplicity this invention was a huge improvement on the previous alternatives which had...
The c90 uses a drum brake design that is essentially unchanged since it was first introduced over 120 years ago.
Renault drum brake
Drum brakes...
C90 chassis
This post explains the design of the Honda Super Cub suspension and steering. If you are interested in fitting tapered roller bearings instead of the standard ball bearing used in the steering head then see here.
Leading Link Forks
All the Honda Super cubs since their introduction in 1958 until relatively recently were fitted with...
This post explains the design of the Honda Super Cub suspension and steering. If you are interested in fitting tapered roller bearings instead of the...
C90 chassis
Internal combustion engines convert the chemical energy stored in fuel into the mechanical energy used to power machines when the fuel air mixture is compressed in the space between the piston and the cylinder head and ignited by the spark plug.
The design of the piston, cylinder and cylinder head plays an important role in...
Internal combustion engines convert the chemical energy stored in fuel into the mechanical energy used to power machines when the fuel air mixture is compressed...
C90 Engine
The first Super Cubs did not have pumped lubrication, instead the crank, piston and cylinder were splashed by oil thrown up by a dipper on the big end of the connecting rod.
A similar device can be seen in towards the end of this excellent video about engine lubrication:
As shown in the diagram above,...
The first Super Cubs did not have pumped lubrication, instead the crank, piston and cylinder were splashed by oil thrown up by a dipper on...
C90 Engine
If you've ever worked on a vintage Japanese motorcycle you've almost certainly struggled with countless buggered-up cross head screws. The usual recommendation to avoid further screw mangling is to put aside your old Phillips screwdrivers and get some "JIS" ones instead.
There is a lot of confusion about this...
If you've ever worked on a vintage Japanese motorcycle you've almost certainly struggled with countless buggered-up cross head screws. The usual...
fixings
The final wiring system to look at on the C90Z2 super cub is the system that supports the lighting and horn. The wiring diagram is a bit more complicated compared to the ignition and charging systems:
It is not as confusing as it first appears though, and if you trace the wires from the various...
The final wiring system to look at on the C90Z2 super cub is the system that supports the lighting and horn. The wiring diagram is...
C90 electrics
The charging system used on the 6v C90 super cubs is pretty straightforward and consists of a battery (to store electricity), an alternator (to generate electricity) and a rectifier (which converts the alternating current created by the alternator into the direct current needed by the battery). Here is the wiring diagram for the charging system:...
The charging system used on the 6v C90 super cubs is pretty straightforward and consists of a battery (to store electricity), an alternator (to generate...
C90 electrics
The job of the ignition system is to produce the spark that ignites the fuel/air mixture in the engine combustion chamber. It consists of a power source (either battery or a generator), a switching device to start and stop current flow at set intervals (contact breaker points or an electronic switch), a device to...
The job of the ignition system is to produce the spark that ignites the fuel/air mixture in the engine combustion chamber. It consists of...
C90 electrics
Electricity
Learning the basics of automotive electrical systems, even the simple system used in the Honda super cub, was something I approached with a little trepidation.
My schoolboy science got me as far as grasping that the electrons in conductive materials like metal can “jump” between atoms, displacing others in the process and thereby causing...
Electricity
Learning the basics of automotive electrical systems, even the simple system used in the Honda super cub, was something I approached with a little...
C90 electrics
