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...

Helpful Links

I have assembled a the list below of the links that I have found useful in support of my CT90 builds:

Information by Model Year, Pictures and the Info

This is the Trail 90 site and has a large amount of model specific info and history
This is another good website that has info on the CT90 as well as just about every other Honda/
This is a link to a parts finder at CMS that is very useful and goes back to early 1960's models
Here is an Instagram link that has a large number of CT90 pictures
Here is the Pinterest link that has a large number of CT90 related photos
This is a good article on the custom Suitcase version of the CT90
This site as some basic info and photos in a Wiki format for the CT90
The actual Wiki site for the history of the Honda CT series of bikes that also has a link to a pdf of the manual here
Here is the Hagerty site where you can get an estimate of the value of your CT90
This site from Australia has a great collection of old Honda ads
Here is a great site for CT90 and other older Honda ad's
Here is a site that provides a brief history of the suitcase version of the CT90

Shop Manuals and Information

Another good source for wiring diagrams is oldmanhonda.com
Old Man Honda also has a nice table of Tune Up Information
DrATV has a nice tech page with with just about all the key CT90 adjustment info
This site sells parts and services, but also has some great CT90 restoration information
This is the process I follow to adjust my idle mixture screw on my CT90 carbs
This is Dan's motorcycle repair site that has a lot of good information
Old School Carbs is a site that rebuilds carbs, but also has a page with very good practical articles on several topics related to carbs and how they work.
Good site for diagrams of Japanese Carbs
This is a great post on a step by step build up of a CT200 engine
This is the NHTSA recall site and there is actually a recall notice for the 1968 CT90
This site has a nice page on how to repair your plastic parts using ABS cement and MEK solvent
This is a nice link on how to remove the small speedometer gear in the front wheel of your CT90

CT90 Parts Sources

My number one place to go for new parts is Beatrice Cycle/DrATV .  Beatrice Cycle is a great outfit in that they have just about everything you may need at fail prices and they ship quickly.

Amazon - Amazon has a large number of CT90 and CT200 components and I put together a page hear at this link where I have tried to organize what is available to make it easier for you to find parts on Amazon.

David Silver Spares has a great selection of Honda and aftermarket parts to the CT90 and is a good source for small detail parts not available at other sites.

What looks to be another source for CT90 and other Honda model parts is 4 into 1. I have now ordered from 4 into 1 and they had what I needed at a good price and shipped fast.

Wincycles doesn't have the greatest selection of CT90 parts, but they do have good prices on jets, floats, carb kits, and a good aftermarket carb for 1970's CT90's.

Mytrailbuddy.com has a good selection of commonly needed parts like clutch disc's, gaskets, etc.

SCI is a good source for carb kits and other CT90 and CT200 parts.

Parts-n-More is a motorcycle parts dealer out of Canada that has a number of CT90 parts and at pretty fair prices.

CHP Motorsports down in Texas is another place that sells CT90 parts that might be worth checking out.

eBay - I have bought a number of parts off of eBay but you need to watch yourself because if you try and rebuild a CT90 off of eBay part by part it can get pretty expensive.

Bonanza - Bonanza is another eBay like site that has CT90 parts.  I haven't yet purchased off of the site, but the prices look lower than on eBay so it might be worth a try.

Local Bicycle Shops - If you ever loose one of the bearing balls that are used in the CT90 headset or other applications like detents in the switch controls on your handle bars check with your local bicycle shop as they usually will have individual bearing balls for sale from their mechanic's shop.

Another good source of parts is to join the Honda CT90 Owners and the Honda Ct90 Buy, Sell, Trade Facebook groups. If you post on these groups and indicate what parts you are looking for there is a good chance someone will respond who has a part to sell.  Its also a good place to sell parts you no longer need.

Craigslist - Detail parts off of Craigslist can be on the expensive side, but if you buy parts bikes you can usually get the parts you need and be able to sell whats left back on Craigslist and in many cases I make money when all is said and done.

OfferUp is an on-line site that is like Craigslist, but has listings both local to your area and also from outside your area. I find that there are less flaky people on OfferUp compared to Craigslist because the communication between people is not anonymous.

Another source for OEM Honda parts is Northeast Vintage Cycle which has a good selection of CT90 parts.

For New Old Stock (NOS) part you can try NOS Parts Now who have a large number of NOS CT90 parts.

For new exhausts I have found that Honda East Toledo has the best price on a new standard exhaust P/N 183A0-102-650 for $121.99 (at the time I wrote this...) which includes free shipping.  The price tends to float around by a few dollars and I have found that when I call their number at 877-437-1631 I tend to get the cheapest price.

Another good source I have found for new Honda parts is Everett Powersports. These guys stock a large number of CT90 parts and always have a great deal where you can get two tubes and two tires for $80.00.

A good source for parts for early Honda's is Ohio Cycle.  They have NOS in addition to some aftermarket and used parts.

CHP Motorsports is another source for CT90 parts and other vintage bikes.

MRCycles is another source for CT90 parts that seems to have very reasonable prices.

MyTrailBuddy is primarily a CT70 shop but they do have a few CT90 parts and its worth a look


Another potential source for one off gaskets would be Cal's Gaskets.  He makes each gasket he sells on his gasket cutting machine and sells primarily through his eBay store, but can also be contacted directly at calstendar@sbcglobal.net.  Cla also sells his gaskets on Etsy if that is where you like to shop.

Tike's Cycle Shop has a unique service in that they can make to order just about any gasket, so if you just need a specific gasket this may be the place to go. Prices are good and they shipped the gasket I ordered for free.  They sell other CT90 parts, but the website is kind of clunky.

Clauss Studios has a unique selection of molded rubber parts for a large number of vintage motorcycles including a few items for the CT200 and CT90.  While they don't have a large number of CT90 related items they would be a great resource for when you pick up other project bikes.

For seat covers there is an interesting site called Cool Retro Bikes that sells kits to recover your seats and also has a service to restore your existing seat. I haven't purchased from them, but they look to be a big step up from getting a seat cover off of eBay.

For repairing plastic parts you might give Plastex a try.  I haven't yet used one of their repair kits myself, but based on other peoples recommendations I plan to give them a try at some point.

Parts Suppliers in Australia
A CT90 parts supplier in Australia you might check out is Motorcycle Spares Warehouse

Another "way down under" source, japbikespares.com, has CT90 pistons and a few other parts that may be just what you need to finish your CT90 project.

Another "way down under" CT90 parts supplier is APB Auto who specializes in CT110 Postie bikes and even has complete bikes to sell from time to time.

Paint and Decals

RepoDecals is an eBay store that sells decal kits for a number of older bikes including CT90's

Another source for paint is Marbles Motors down in Texas

Beatrice Cycle/DrATV also has a nice post from one of their customers on various paint options.

Tires and Wheels

CRT Cedar Rapids Tire - I recently purchased a set of ties for my CT90 from CRT as they had a great price on DURO HF307's 2.75x17 at only $23.12 and rim strips were only $1.99. They also had very fast shipping.

American Motor Tire is another option for CT90 tires.


Keys
For keys, I have used hondakeys.com   to get keys for several bikes where I didn't have a key or wanted an extra key and was very happy with the keys I received back from my order.  Most of the keys are factory cut from Honda.  You provide the model of your bike (CT200, CT90, etc.), the number on your lock or ignition (usually a format like T-XXXX or H-XXXX), the year of your bike and the VIN#.  The cost per key on my last order was $14.00 plus shipping.
Another option is to find the right key on eBay or buy blanks on eBay and have them cut by at a local hardware store or locksmith.

Another option for keys would be Thumb Online Cycle.  I haven't used them yet myself, but may give them a try the next time I need a key for one of my bikes.

One more option for keys is Cycle Keys Online where each key is just $10.99.  I haven't used them yet but plan on giving them a try in the future.

Electrical

If your looking to upgrade to an electronic ignition or a much better rectifier, you might check out Charlies Place

For connectors and other various wire terminations you might want to check out Vintage Connections

Another source for wire terminals and connectors is Cycle Terminal which looks to have a great selection of items needed to repair just about any wire issue you might have.

If you are looking for basic automotive grade wire for repairing your wire bundles CrimpZone is an option

For batteries I have bought a number of these batteries from Amazon and each one of them has been great. The battery comes with electrolyte, and are only about $9.00, and come with free shipping!

For new rectifiers try  Pardue Brothers

For rebuilt stators and other electrical items you might try Rick's Motorsport Electrics

Another potential source to get your stator rewound is Ricky Stator

And a third potential source to get a stator rewound is RegulatorRectifier.com

LED instrument bulbs - SuperBrightLEDs has 6 volt BA9s LED bulbs that I plan on giving a try in the future for use in my CT90 speedo's as replacements for the stock bulbs.

An interesting source for generic wiring related components is Rhode Island Wiring Service Inc. They have wire by the foot in just about any color combination you might be looking for.

If you were think about doing an electric conversion of your CT90, you should check out this link.

CT90 Machine and Restoration Shops, Engine Mods

This is a new page I am building of CT90 shops from around the country and the world.  If you know of a good shop that bores cylinders, send me a note and I'll add them to the list.

Classic Moto Works is a shop that does restoration and custom builds in WA state.

Cumbus Cycles is a small shop that does complete restorations of vintage motorcycle engines and may be an option if you're in the Baton Rouge, Louisiana area.

Another source to get your speedo rebuilt is Foreign Speedo Inc. in San Diego.  I think they charge about $100 but are known to do a quality job.

If you are looking for restoration services you might check out Mikes Minitrail Restorations who primarily focus on Honda 50's and 70's but also looks like he will do work on CT90's

TBolt USA is a source for Lifan engines and the adapters needed to bolt one on to a CT90 or CT110

Ethanol Free Gas

This website at this link provides a list of gas stations by state that sell ethanol free gas. Running ethanol free gas seems to allow your CT90 to start easier and run better.

Shipping a CT90

If you ever have to ship your CT90 you might check out this website that has a list of shippers who will ship motorcycles.

Forums - These forums are great places to get help and information

Honda Trail CT90 & CT110
Lil Honda
The Vintage Japanese Motorcycle Club
Motorcycle Forum Vintage Page - Not dedicated to CT90's but a lot of great old bike info
IH8MUD is another general site focused on off road, but has CT90 content if you dig a little


People Roaming the World on CT90's
This is Ed March's website and while he may no appeal to everyone (I really like the guy...) he sets the standard for roaming the world on a C90.  If you search on YouTube you'll find a number of the video's he has made and I think there great fun to watch.

This is Rachel's website who is associated with Ed March (I think its a complicated relationship...), but she goes to some amazing places on her C90.

This website has a review of a book by Nathan Millward who road a CT110 from Sydney Australia to London England and it sounds like a pretty eventful trip!





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