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Honda CT90 Engine Reassembly

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I have one 1971 CT90 where I was going to rebuild the clutch because the kickstarter just wasn't turning over the engine like it used too,  and I also had a Big Bore kit from DrATV that I wanted to install. My intent was to just do the top end and rebuild the clutch with new disks, but when I opened up the cases to rebuild the clutch pack I found a slick black slime in the bottom of the case.  I didn't like the idea that there could be black slime in the rest of the engine, so I decided to disassemble the entire engine to make sure I cleaned everything out.  Since I was tearing everything apart I thought I would document step by step how everything goes back together in this post in case others were interested in knowing what the inner workings of a CT90 engine look like. Links to Related Posts: My Honda CT90 Clutch and Headset Nut Tool Cut Away of a CT90 Engine - CT90 Engine Exposed! Repairing Damaged CT90 Spark Plug Threads Using a Time-Sert Thread Insert CT90 Cl...

A Few More 3D Printed Parts for use on a Honda CT90

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Here are a few more Honda CT90 3D printed parts I modeled and printed recently. Two of the designs were successful while one never got to the point of being acceptable enough where I would share the .stl files. Related Posts: A New Batch of 3D Printed Parts that Can Be used on a Honda CT90 and CT200 More 3D Printed Honda CT90 Part Designs 3D Printed CT90 K1 Rear Airbox Snorkel CT90 K1 3D Printed Carb to Air Filter Boot A 3D Printed Valve Spring Compression Tool Throttle Hinge and Cable Holder While working on one of my bikes recently I had the throttle assembly apart and it got me thinking about the feasibility of modeling and 3D printing the throttle hinge and cable holder.  While these parts are not hard to find, they would make a nice challenging part to design and 3D print. The first part I made was the cable holder which is a pretty straight forward part to design. The gray part below was printed with PLA and the orange one...

A 3D Printed Piston Holding Tool for a Honda CT90

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Maybe I'm just getting old, but when I am rebuilding a CT90 engine one of the things that can be a little bit of a pain is holding and compressing the rings on the piston when you're sliding on the cylinder.  Sometimes its not to bad, but other times I fuddle around before I can get it to all come together. Related Posts: CT90 Engine Reassembly I decided to design a removable tool that I can 3D print, that helps support the piston, so I can focus more on compressing the rings while installing the cylinder.  The tool is also nice as a way of closing off the opening to your crankcase to keep dirt and crud out if your engine is going to have the cylinder off for an extended amount of time. Here is what the tool looks like installed.

More 3D Printed Parts for Use on Honda CT90 & CT200 - Hard to Find K1 Parts and Others

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I'm continuing to find and endless number of opportunities to utilize my 3D printer to make useful parts for my CT90 project bikes, my fishing float tube, and other hobbies that I have.  I thought I would share a few of the latest CT90 parts that I have designed/modeled and printed. All of the designs I share below, I first modeled using my ViaCad 2D/3D modeling program. Related Posts: A New Batch of Honda CT90 and CT200 3D Printed Parts More 3D Printed Honda CT90 Part Designs 3D Printed CT90 K1 Rear Airbox Snorkel CT90 K1 3D Printed Carb to Air Filter Boot A 3D Printed Valve Spring Compression Tool CT90 K1 Front Fork Cover Side Reflector Base On almost every older CT90 I work on (I guess they are all old...) the little rubber caps on that cover and help hold in the bulbs on the base of the speedo are cracked, disintegrating before my eyes or are just missing. I modeled up both a short cap that has a hole for one wire and a tal...

A new Batch of 3D Printed Parts that can be used on a Honda CT90 and CT200

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 I'm continuing to find and endless number of opportunities to utilize my 3D printer to make useful parts for my also endless number of CT90 project bikes that I am working on, so I thought I would share a few of the latest CT90 parts that I have designed and printed. All of the designs I share below, I first modeled using my ViaCad 2D/3D modeling program. Related Posts: More 3D Printed Honda CT90 Part Designs 3D Printed CT90 K1 Rear Airbox Snorkel CT90 K1 3D Printed Carb to Air Filter Boot A 3D Printed Valve Spring Compression Tool Speedo Light Bulb Socket Caps On almost every older CT90 I work on (I guess they are all old...) the little rubber caps on that cover and help hold in the bulbs on the base of the speedo are cracked, disintegrating before my eyes or are just missing. I modeled up both a short cap that has a hole for one wire and a taller cap that has a slot in its base that allows two wires to pass through as shown in ...

More 3D Printed Part Design that can be used on a Honda CT90

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I've been having fun modeling a number of Honda CT90 parts and then printing them on my printer. and I thought I would share them here along with links to .stl files in case others wanted print parts for their own individual use. To create all of the parts I share below, I first created a 3D model in my ViaCad 2D/3D modeling program. Ignition Switch Access Hole Plug The first part I will share is my design for the rubber plug that goes in the hole where the wires from the ignition switch exit. I have printed this plug using SainSmart TPU filament which is flexible enough so the plug can be installed, but it is not near as flexible as a new stock rubber plug, but much more flexible than a 50 year old rock hard stock rubber plug. Here is the link to the .stl file at PrusaPrinters for the ignition hole plug.

A 3D Printed CT90 Valve Spring Compression Tool

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 Since I picked up a 3D printer this Christmas, I've really found that it's a great tool, especially if you have a good 3D modeling program on your computer and reasonable skills to be able to design the part you would like to print. For a limited time I am including for free one of my prototype valve spring compression tools that I describe below with the purchase of my clutch holding tool available here at this link . My fundamental problem has been that I keep coming up with new designs I would like to print and get them 90% complete, before I get another idea and I'm off on another tangent (such is the life of a retired guy...). One of those designs is a Valve Spring Compression tool to use on a Honda CT90.   I've been using a C-Clamp and simple piece of tubing as my valve spring compression tool up until now and it always works and gets the job done.  I've done a post here at my blog on the C-Clamp tool here at this li...

A 3D Printed Rear Airbox Snorkel for use on a Honda CT90 K1

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One of the other parts I recently modeled and made a 3D print of is the rubber Snorkel/boot that attaches to the rear of the 1969 K1 CT90's airbox, and that resides in the battery compartment area in the frame when the airbox is installed. Here is a picture of the model I made in ViaCad 2D/3D. The following are a couple of photos of the snorkel that I printed using a flexible TPU filament next to the stock rubber snorkel that I removed from the airbox. The 3D printed snorkel has a nice snow fit when it is mounted to the cylindrical feature on the airbox. Here is the link to the .stl file for the snorkel at Prusaprints I hope you found this information useful! Helpful Links  (Shop Manuals, Wire Diagram, Model Information, etc.) Link to page with listing of CT90 and CT200 parts available on Amazon