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Showing posts from March, 2019

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 Clutch P

Honda CT90 Engine Fasteners

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I put this post together as reference for the length of the fasteners used in a 1972 Honda CT90 for assembling the engine cases and covers, but also for some of the fasteners used internally within the engine. Screw size convention Example: M6 x 1.00 x 20 M6 - is the diameter of the screw, which in this case is 6mm 1.00 - is the thread pitch of the screw in threads per millimeter 20 - is the length of the screw, which in this case is 20mm On a few items like pins and a washer I provide dimension in inches instead of mm. Right Side Clutch Side Cover Screws Two  M6 x 1.00 x 40 Seven  M6 x 1.00 x 20

Using a VW Lug Bolt as a Puller to Remove a Honda CT90 Generator Rotor

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I had read online that the wheel lug bolt from a VW had the same thread as what is in the center of the generator rotor on a Honda CT90 and makes a good tool for removing the rotor, so I thought I would give it a try. I went on to Amazon and found a VW lug bolt and it was only $5.00, so I added it to an order I was making.  The VW lug bolt has a 14 x 1.5 mm thread which is the same as what is in the inside diameter of the generator rotor that is intended to be used for the rotor removal.