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Showing posts from June, 2018

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

How to Test Your CT90 or CT200 Rectifier

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One part on the CT90 that can degrade with time and also cause a variety of issues that don't seem to have an obvious cause is the rectifier. Links to Related Posts CT90 Rectifier Upgrade Basic Test of a CT90 Condenser Basic CT90 Ignition Coil Check If you have an old CT90 that you are trying to bring back to life, I would recommend just going ahead and upgrading your rectifier to a newer more modern solid state design and I made a post here on how to do that yourself .  But if you would like to use the rectifier that came with your bike or if you are really trying to restore your CT90 back to the original configuration, I'll show you how to test your rectifier to see if it is good or bad as it's really a very simple test to do.

How to Test Your CT90 Condenser

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One item often overlooked on a CT90 when trouble shooting is the condenser that is mounted with the ignition coil.  The primary function of the condenser is to prevent arcing at the ignition points when the points open which results in a spark being generated at the spark plug.  The condenser also to a lessor degree, helps maintain the spark at the spark plug. Links to Related Posts CT90 Rectifier Upgrade Basic CT90 Ignition Coil Check How to Test Your CT90 Rectifier Unlike CT90 ignition coils which can be 50 years old and still be in great shape, a condenser is really just a capacitor and capacitors can and will degrade with time, so its always worthwhile to take the time to test the condenser, especially if you have gone to the trouble to remove the coil/condenser assembly from your CT90. There are a couple of different ways you can check your condenser to determine if it is performing correctly. The first approach is to make a couple of subjective observations on your CT

Repairing Damaged CT90 Spark Plug Threads Using a Time-Sert Threaded Insert

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I had a cylinder head where the threads for the spark plug hole had stripped out and needed to be repaired and I decided to use a Time-Sert to repair the treads.  This was my first time using a Time-Sort so I decided to do a post here to share the process that you go through and what the final installed insert looks like.  I have used Helicoil's in the past to repair damaged threads on other bikes I have owned so I first started to look for a Helicoil repair kit and the ones I found were around $48.00 dollars which sounded high and while I find Helicoil's fine for most repairs, for a spark plug hole they are not really idea in my opinion as you'll be removing the spark plug on a regular basis and I would prefer something more robust and permanent. In digging around on the internet I came across Time-Sert thread repair kits that use a very robust looking insert which I liked, but I was shocked at the price of the kits where the cheapest I could find was still around $88.0