Honda C90 – Valve Timing
Here are a few posts on the topic of valve timing and valve adjustment. Happily, since the c90 is such a simple engine, it is …
Honda c90 – tool kits
Looking at the CMSL microfiche parts diagrams, the older Kowa tool kits – for example the c100 from the 1960s – contained: an open ended 10/14mm spanner …
Kowa tools
Kowa Seiki have made tools for Honda since 1956, initially making their special workshop tools and then going on to make the tool kits for …
Honda C90 – carb – cleaning and replacement parts
There are only a handful of things that can go wrong with the simple carburettors used on the Honda c90 and – once you have …
Honda C90 – carb choke
When the engine is cold fuel tends to condense on the walls of the intake manifold and cylinder and this make the engine hard to …
Honda C90 – carb idle circuit
The idle (or “pilot”) circuit controls the mixture of fuel and air at low throttle speeds. Here are the bits involved in the pilot circuit …
Honda C90 – carb main circuit
This Kehin carburettor has two independent systems for metering fuel and air, the main circuit and the idle circuit. As the names suggests the idle …
Honda C90 – carb fuel and air mixture
We already saw that the basic function of the carburettor is to mix fuel and air in the right proportions before it is ignited in …
Honda C90 – carb float height
The level in the float chamber effects the ratio of fuel and air passed to the engine: when the level is too high the additional …
Honda C90 – carb drain, overflow & breather tube
There are a few other bits involved with the carburettor fuel supply: the overflow, drain screw and breather The purpose of the drain screw is …