The speedo used on the 1969 Ct90 k1 speedo is a one-year-only version with a distinctive triangular shape. My bike was fitted with a later version - the replacement I found is shown in the middle below.

left: pre-1969 version / centre: K1 1969 / right: later version (note sticker explaining how to use the handlebar lock used on the K2 and later CT90s)

Although almost identical to the K1 model, the version I managed to get hold of is actually from a S90 of the same era. This can be seen by the orange gear change indicator marker shown on the printed speedo face, which go up to a wapping 65mph to reflect the sportier version of the engine fitted to the S90 compared to the 57mph theoretical top speed for a CT.

*edit I did eventually manage to find a genuine CT90 k1 version - before and after below (the mechanism was broken, but I was able to switch one from another broken speedo).

Replacement

This is the speedo and headset received with the bike:

The fork covers, headlight, headlight case and speedometer are all wrong for a K1 (the handlebars, handlebar clamps and fork bridge plate are all correct though)

...and this is how the replacement speedo looked when I got it.

In what appear to be common faults, the white surround was tarnished by exposure to sun and rust and the coloured plastic lenses were missing as were, perhaps unsurprisingly, were the light bulbs and bulb holders.

Bulbs

I didn't really want to dismantle the speedo to fix the missing coloured lenses, having messed this job up in the past, so considered using colored LED insteads. I gave up on this idea for a couple of reasons: the first is I ordered the wrong LEDs (I assumed they were 9mm but they are actually all 7mm). As it happens the shop I got the bulbs from - LED Bulbs for Classic Cars (Ebay) - does do BA7S LED bulbs but they do not stock amber versions. The very helpful people who work there answered my query about why:

Amber as a BA9S/BA7S fitting in LED is not that bright. The head needs to be a lot larger to get enough SMD's on it to give a bright output. Where you have an amber lens, we recommend the use of warm white LEDs, a similar colour output to incandescent lamps so will work well behind an amber lens. Cool white would just wash the colour out.

6v BA7S bulbs are still available in the UK from Lucas

made by Lucas (type 282)

The second reason is I decided it would look a bit crap without lenses.

Dismantling

... so I bit the bullet and unpicked the outer cover so I could glue in some coloured perspex. Much to my surprise the amber and green oblong lenses were stuck to the inside of the speedo!

There is no real art to prying off the stainless steel trim, just go slowly and go round several times prying the lip up a small amount each time. You need to go equally slowly when tapping it back into place.

I used a bit of red perspex to replace the small high-beam indicator (in the olden days Honda used red for high beam, switching to blue at some point in the 70s). I glued all the lenses onto the back of the speedo face with epoxy. It was also a good opportunity to clean the white surround.


Although It is possible to reset the clock back to 000000, it is a semi-destructive process as you have to cut of the folded over tabs that hold the drum in place, and i did not want to risk breaking it and have therefore stuck with the no less arbitrary 14k miles.

Rear connections

Here are the light bulb is the rear connections

Note that the brown (rear light) and blue (high beam) are grounded through he case. The orange/blue (signal indicator) and light blue/red and black (neutral) are isolated from the speedo case. Don't forget to clean up the inside of the bulb holders so there is a solid ground connection to the bulb.

Fork covers

As noted above, the K1 came with a smaller headlight than subsequent models, and as a result the fork covers are also a different design with smaller fork 'ears':

K1 fork covers (left) and later models (right)

I managed to get the correct fork covers from a red CT90 that was being broken for parts in the UK (although I noticed later you can still get them NOS from David Silvers). The Headlight bucket is still available, but not in the CT90K1 red colour. The smaller headlights were used on a number of small Hondas in the UK and are not difficult to find on ebay.

The only other thing old rubber gasket fell apart immediately - I had to order a replacement from Thailand. Here is the finished job