CT90 Restoration Adventures

Something that is often overlooked when someone picks up a used CT90 is the condition of the rubber dampers in the hob of the rear wheel.  These rubber dampers are important in that they help reduce the loads generated in the drive system when they are in good condition and can generate significant loads in the drive system if they are worn. You can do a basic check of the condition of these dampers without having to disassemble anything on your CT90 and it really only takes a few seconds to do.  I have prepared the video below to show a CT90 which have dampers in good condition and all a CT90 where the dampers are worn and need to be replaced.

The primary goal in setting the timing on your CT90 is to have a spark occur at the spark plug due to the points opening up when the piston is at the ideal position before top dead center with both the exhaust and intake valves closed. In the write up below I will share how I go about adjusting the timing on a CT90 and I will be doing this on an engine setting on my bench, but everything I share below is equally applicable for an engine mounted on a bike. Related Posts Cut away of a CT90 Engine - CT90 Engine Exposed! My Process to get a CT90 that won't Start to Start Adjusting and Jetting a CT90 Carb CT90 Engine Assembly Honda CT200 Engine Reassembly Building a static timing light from a free Harbor Freight LED Light To set the timing on a CT90 there are four main steps: 1. Making sure that the timing chain sprocket that drives the overhead cam is installed at the correct position on the timing chain relative to the crank/piston assembly 2. That the valves are adjuste...

A while back I was working on one of my basket case K1 CT90's and needed a spring for the brake light switch that is actuated by the rear brake lever and brake pedal.  At the time DrATV/Beatrice was out of stock of the spring so I decided to find another spring to do the job as I was more focused on getting something that worked and less on having be a picture perfect restoration. Here is a picture from one of my other CT90's on what a stock spring looks like in this application. My goal was to find a replacement spring that had the same stiffness as the stock spring and I ended up finding a spring on Amazon that had the right stiffness and looked like I could make it work. iIt was only $2.89 for two springs, so I decided to give them a try and added the springs to my next Amazon order. Since the spring from Amazon was not the same length I had to add a section of bailing wire to get a final configuration that would fit in the same location as a stock spring.  He...

Updated 11/11/17 to correct the section on installing the high range gear where I left out the step to install the splined washer and retaining ring after the high range gear is installed. I was building an engine for a project CT90 and was reassembling the sub-transmission and thought I would capture the build of that assembly here as a post for future reference and for anyone else to utilize if they happen to be working on this portion of a CT90's engine assembly. Here is an overall picture of all of the parts that go into the sub-transmission assembly