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Showing posts from February, 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

Troubleshooting a Honda CT90 that won't start to start

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Most everyone who adopts an old Honda CT90 at some point gets to where the bike won’t start and your first instinct is to start making random adjustments, but no matter how many times you adjust or clean everything the bike just won’t start. After doing this a number of times myself I now try and take a more methodical approach where I follow the sequence of steps I have outlined below, and I’m usually successful at getting the bike running again. Others may take a different approach, but I thought I would share the items I look at and the order I look at them in case this information is useful to someone else dealing with trying to get a CT90 to start. Step 1 – Do you have good compression? Fundamental to getting a bike running is having a reasonable amount of compression, and the more you have the better. If you have a compression gauge put it on and see what you have, but if you have greater then 80 psi that should be adequate to start the bike. If you don’t have a compressi

Making a CT90 Internal Battery Bracket

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A common item that is missing on a lot of old Honda CT90's is the sheet metal bracket that helps cradle the battery in the opening on the side of the frame.  When the battery is removed there really isn't anything retaining the bracket, so it can very easily get left out and ultimately lost. You can sometimes find a used inner battery bracket on eBay, but lately when I have needed one I just make one as it is a very simple part and if you own a pair of tin snips and are a little bit crafty, you can make one in a few minutes. I made the attached drawing below to help others who may be in a situation where they need a inner battery bracket and would like to fab one up, but are looking for the overall dimensions of the bracket. The drawing does not have the dimensions for the depressions stamped into the original Honda designed bracket that add stiffness to the part, but the design on the drawing will give you a good functional part. I hope this post was helpful and ha