Honda CT90 (Trail 90) Specs, Manuals, & Parts


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If you’ve got a CT90, or Trail 90, that you’re working on, you’ve come to the right place.

Whether you’re doing a full rebuild or restoration motorcycle project or you just need to complete some routine maintenance, we’ve got all the information and links to what you need to do the job right.

On this page you’ll find:

  • Links to the motorcycle service manual for your CT90.
  • Where you can buy aftermarket, OEM, and NOS parts for your bike.
  • Where you can find used CT90s for sale to start a new motorcycle project or get a parts bike.
  • Specs, details, and information about the history of the CT90. may earn an affiliate commission when you make a purchase through the links on this page.

Honda CT90 Service Manuals

The motorcycle service manual should always be one of the first things you pick up when you buy a new bike.

Whether you’re doing a full rebuild or just need to do a standard tune-up, having the proper owner’s manual is going to ensure you do the job the right way.

Find the CT90 service manual you need at the links below: has ready-to-download service manuals for a variety of years and model variations. Get yours today and get the job done right!

CT90 Aftermarket & OEM Parts

Sometimes finding the right parts for your bike can be as challenging as the repair itself.

If you’re working on a CT90, check out some of the resources below to find new and used replacement parts.

Be sure to confirm the fitment for your bike’s year and model variation.

Cams, Rockers & Valves

If you’re rebuilding the head of a CT90, you’ll need to pick up some new valves, seats, and seals.

Bigger jobs or engines that are in rough shape, may require new camshafts, cam chains, and rocker arms too.

Carburetor & Fuel Parts & Rebuild Kits

Carburetors are a “must-service” item for any motorcycle rebuild or restoration project.

Sometimes an aftermarket carb rebuild kit for your CT90 will do the trick. Other times, you may need new carbs altogether or specific OEM parts to get the job done right.

Clutch Parts

If your CT90 project has been sitting for a while, you may need to replace the clutch’s steel and friction plates.

Some other clutch parts you may need include:

  • Clutch levers.
  • Clutch cables.
  • Clutch basket, bolts, and springs.

Electrical, Ignition & Charging System Parts

Electrical systems on project bikes can be a source of all sorts of problems. If you’re experiencing electrical issues with your CT90, this is the parts category for you.

Find the right:

  • Wires and wiring harnesses.
  • Headlights, tail lights, and turn signals.
  • Switches, fuses, and relays.
  • Regulators and rectifiers.
  • Ignition units.
  • Coils and spark plug wires.
  • Starter motors.
  • Alternators.

Engine Gasket Sets, Cases, and Covers

If you’re doing any sort of engine work on your CT90, you’ll definitely want to pick up a new gasket set.

You can also find things like used replacement engine covers and stainless steel bolt kits.

Pistons, Piston Rings & Cylinders

If you’re tearing into your cylinders, you’re probably going to need a new set of piston rings.

If your CT90 engine is seized, you can get a replacement cylinder block and new pistons as well.

Side Covers, Body and Frame Parts

Find side covers, foot pegs, frame parts, and fairings for your CT90.

Suspension & Brake Parts

Check here if you need to replace your CT90 brake pads, brake levers, or service your forks and rear suspension.

Wheels, Hubs, Chains & Sprockets

If you need to replace your CT90 drive chain and sprockets or service your wheels and hubs, find the right parts here.

Where to buy parts for a Honda CT90?

Some other good places to find parts for your CT90 include:

CT90 Specs & Details

The Honda CT90 “Trail 90” was the first true dual sport motorcycle.

It was manufactured from 1966 to 1979 following some dealer-specific modifications that were popular in the U.S.

The CT90 was designed for the trail and the outdoorsmen, but also suited city commuters and those who needed something to get around and work a large property.

The bike was designed to be easy to use on tight steep trails and for hauling gear.

It was also designed to be rugged. The design of the intake made it so that bike could be pretty much submerged and continue running. The spark-arrestor exhaust made it safe for off-road use.

Early models featured a dual-sprocket, which the rider would need to swap on the hub and add a chain to use the low gear climbing capabilities.

Later models included a sub-transmission gear box, that allowed you to make the switch by coming to a stop and flipping the lever.

The CT90 also features an automatic clutch. Shifting through the gears simply requires the foot, and forward motion just requires the throttle. When the bike comes to a stop, it won’t try to move until you give it throttle again, making it ideal for steep, narrow trails.

Specs for the Honda CT90 include:

  • Top Speed: 55 mph.
  • Engine Displacement: 89cc
  • Cylinders/Engine Type: 1, overhead camshaft.
  • Transmission: Automatic 4 speed. dual sprocket on early models, dual-range on later models. Gearing pattern goes N 1 2 3 4
  • Wet Weight: 200 pounds.

CT90 Years & Variations

  • 1966 CT90 K0
  • 1967-68 CT90 K0 (introduction of the dual-range sub transmission).
  • 1969 CT90 K1
  • 1970 CT90 K2
  • 1971 CT90 K3
  • 1972-73 CT90 K4
  • 1974 CT90 K5
  • 1975 CT90 K6
  • CT90 ’76
  • CT90 ’77
  • CT90 ’78

Find a Honda CT90 for Sale Near You

If you’re looking for a CT90 of your own or need a donor parts bike for your current motorcycle project, you can use the used bike search tool to find what you’re looking for.

Click your state below to find used CT90s near you.

These motorcycle search engines search Craigslist listing for the entire state so you don’t have to individually search each specific region.

Once you’ve got the bike up and running, be sure to check back to our motorcycle registration and title guides if you need help getting plates (Especially if you’ve bought the CT90 without a title).