Honda CT90 - muffler and spark arrester

Honda CT90 - muffler and spark arrester

The CT90 exhaust system, although similar in appearance to the one used on the 6v C90, has different internals with fewer baffles and the addition of a Krizman spark arrester. Spark Arresters Spark arresters are designed to minimise the risk of fires being started by exhaust sparks and are required in the US when using...
The CT90 exhaust system, although similar in appearance to the one used on the 6v C90, has different internals with...
Honda CT90 - Front Suspension

Honda CT90 - Front Suspension

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...
Honda CT90 (k1) - wiring diagrams

Honda CT90 (k1) - wiring diagrams

I am recommissioning an 1969 CT90 k1, imported to the UK from California. One of the many jobs needed to get the bike running is to replace the damaged wiring harness, so I've colourised the wiring diagram to make it easier to read. You can get a copy below. Full diagrams When the...
I am recommissioning an 1969 CT90 k1, imported to the UK from California. One of the many jobs needed to...
Honda C90 - crankshaft refurbishment

Honda C90 - crankshaft refurbishment

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...
Honda C90 - putting it back together

Honda C90 - putting it back together

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,...
Honda C90 - air cleaner and exhaust

Honda C90 - air cleaner and 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 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...
Honda C90 - Crankshaft

Honda C90 - Crankshaft

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...
Honda C90 - transmission and performance

Honda C90 - transmission and performance

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...
Honda C90 - brakes

Honda C90 - brakes

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, as shown in the patent diagram below left. Despite its apparent simplicity, this invention was a huge improvement on the previous alternatives...
The c90 uses a drum brake design that is essentially unchanged since it was first introduced over 120 years ago....
Honda C90 - forks, suspension and steering

Honda C90 - forks, suspension and steering

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...