My CT90 was in fairly typical condition for the CT90s we get in the UK: a few missing and mismatched parts but in otherwise sound condition and minimal corrosion on account of having spent its previous life in California.

The keen eyed among you will notice that the headlight bucket, lens, speedo and fork ears are all from a later model. Luckily the headlight bucket from an S90 is still available and the same as the one fitted to the CT90 K1 (the replacement is on the right). The lenses are the same as on the older C90s sold in the UK and therefore relatively easy to find secondhand. By a sheer fluke, a UK based breaker parting out the remaining bits of an old K1 so I managed to get the fork ears and side cover replacement at a reasonable price..

Paint

Honda described the red colour used on earlier CTs as 'scarlet red' but when I tried a rattle can purporting to be this colour it seemed to me to be far too dark. In the end I used Tahitian Red - the red colour used on later models - and although it is far from a perfect match, the orange colour is a bit closer to the now quite faded paint on the rest of the bike.

The replacement down tube cover is new and is from a Ct110 (these are still available from Honda). The new covers fit the older bikes too - albeit with a slightly larger 'bulge' to accommodate the CT110 carb. It was the wrong colour so I painted it and the air cleaner cover GM Dark Grey. To my eye it is a not bad match to the colour shown on the adverts for later models, but it seems darker that the photos of original 1969 models I've seen (although presumably these are all pretty faded by now).

the K1 airbox cover is unobtainable, so I was lucky to get this with the bike - I painted it to match the resprayed down tube cover. Finally, I had to contrive a standoff to hold the cover in place.

Rear suspension

The rear suspension was in pretty rough condition as might be expected on a 55 year old bike. The right hand plastic cover has the tell tale CT90 damage where it has come in contact with the exhaust, so that needed replacing. The rest of it was serviceable and just needed a clean up.

The oil dampers in these shocks are not serviceable and any oil that leaks past the rubber seal inside the mechanism will reduce its effectiveness, no doubt fuelling complaints that the older bikes are under-damped. The damping was surprisingly good on the ones above, considering the age.

Rear Swingarm bushing

The rear swing arm pivots on the frame via rubber bushings and - although Honda do suggest they should be checked and replaced in case of damage excessive wear and aging - they are very robust and the consensus is they can generally be left alone.

If, like me, you are bloody minded and want to replace them anyway then be warned that they are a bugger to get out.

Having done this a few times now, I've found that using a 3mm drill to remove the inner rubber section makes the job much easier: drilling holes at regular intervals weakens the bond to the inner sleeve so it can easily be pushed out with a vice. If - before removing the inner sleeve - you use a larger drill (5mm) to make two more holes 180 degrees apart between the inner and outer sleeves it breaks through the outer sleeve and the whole things pushes out easily in one go. It is hard to avoid marking the inside of the fork when drilling the larger holes, but the bushes are such a tight fit there is basically zero chance of them moving when reinstalled, and I don't think this is a serious problem (you could probably avoid it with a bit more careful drilling if you are worried).

Be sure to remove any raised burrs on the inside of the forks and the new bushes will push in with a vice or press.

that's it!