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Showing posts from January, 2017

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...

Soldering a Wire

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A lot of times when you pick up an old CT90 some part of the wire harness may be damaged and need to be repaired.  While everyone who works in their shop or on bikes and vehicles knows how to solder to some degree, I thought I would provide a little electrical help and share how I go about soldering two wires together to repair a wire harness. The first thing I will say is that if you plan on bringing old CT90's back to life on a regular basis keep an eye out for old partial wiring harnesses and pick them up when you can.  Being able to salvage sections of wire in the right color and with a pin or socket at the end always makes for a much easier and cleaner repair. Some people may ask why not just use a crimp style butt connector to join two wires.  While a butt connector would work and be functional, it's not that clean and over the life of a bike I feel a nice soldered joint will hold up much better and less likely to give you a problem when your 10 miles up an old...

CT90 or CT200 Rectifier Upgrade

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One of the most common items to find not working on old CT90's is the rectifier.  While a CT90 may start with a poor rectifier the rectifiers primary purpose is to take the alternating current from the genorator in the engine and convert that to direct current or voltage to charge the battery. If you are looking for information on how to test your existing CT90 rectifier, I made a post at this link that includes a step by step process for performing the test. While you could always purchase a new rectifier from any one of the outfits that carry replacement CT90 parts, one of the cheapest ways to go is to get a rectifier from Radio Shack that will only cost about four dollars, but does require some minor modifications to the wiring on your CT90.  If your looking to do a complete restoration by all means go out and spend the $15.00 to $30.00 for a replacement rectifier, but if you looking for a cheap but very robust solution, go down to your local Radio Shack and pick up t...

Buying a CT90

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General Thoughts - Updated 1/10/19 When buying a CT90 you need to decide beforehand what you are really looking for with respect to do you want a project to work on or do you want a fully restored bike that starts first kick. There are no hard and fast rules with the price you should expect to pay as it varies widely and a lot of the time the price may be driven by what someone has put into the bike while they have owned it. Below I'll provide you my opinion on what you might pay for bikes in various conditions and also some of the dealsI have come across and what I look for when I am buying bikes for a new project. In general I have found that older CT200's or CT90's without the dual range transmission will go for less than CT90's with telescoping front forks and a dual range transmission. The older CT200's with a pushrod engine are a fun bike to work on, but parts are not as readily available, so if you do go down that path be aware it will be a little mor...