CT90 Restoration Adventures

I am in the middle of adding a DrATV Big Bore Kit to my 1971 Honda CT90 and when I pulled and disassembled the head both the exhaust and intake valve had a pretty significant groove around the area where the valve seats.  The bike was running fine before I pulled it apart, so I could have just cleaned everything back up and used the old valves, but since I had it apart I figured I would replace the valves if I could find a set that wasn't too expensive. I spent some time on eBay and kept seeing sets of valves made by Shindy with a part number of #07-002.  The funny thing was when the ad on eBay was for a CT90 the price was around $19.00, but I noticed the same set of valves being sold for Honda ATC's with no mention of CT90 and the price was only $13.55 with free shipping from within the USA which I thought was a great deal. I ended up ordering the valves from eBay seller parts_giant and in a few days the parts showed up in my mailbox.  You can also get this set of valves

I am in the process of installing a DrATV Big Bore kit on a 1971 CT90 that I own and I am also replacing the clutch disks at the same time, so since I was into the engine that far I figured I'd pull the other side cases and clean them up and paint all three side case that came originally painted from Honda. This is the first time I have painted the side cases on one of my motorcycles, so I spent a little time searching the web to see what other people were doing as far as what paint to use. T settled on using the self etching primer and paint color shown in the picture below.

I was working in my shop the other day prepping some side cases for paint from one of my CT90's and noticed the "PAT. APPLN. PEND" that is cast into the side of one of the cases just above the high/low range gearbox and selector and I started wondering what if anything, Honda had actually patented on the CT90.

In this post I want to share a very simple and inexpensive way to build a clutch holding tool with plumbers tape. Update: I now make and sell a clutch holding tool that also can be used to loosen your headset nuts and more info is available here at a post I made at this link . There is a good chance with every Honda CT90 that at some point in its life you are going to have to rebuild the clutch.  Rebuilding your clutch isn't really all that difficult of a task to do, and it has the added benefit of allowing you access to clean your oil screen and also to check to make sure your shift drum stopper hasn't developed any cracks (see: Shift Drum Stopper Replacement When Doing a Clutch Rebuild ) While the overall effort to replace your clutch disks is very straight forward, there are two steps in the process that can be a bit of a pain if you don't have the right tools.  The challenging steps are with finding a way to hold the clutch assembly and keep it from rotating wh