Honda Trail 70 (CT70) Mini Bike Specs and Review

One of Honda’s most illustrious gems is, no doubt, the Honda Trail 70 (CT70). Introduced in 1969, this classic minibike succeeded the Honda Z50 both in fame and features. Portable and highly capable, the CT70 may well be the greatest antithesis for those who believe that riding a supermoto is the only way to enjoy the outdoors.

The Honda Trail 70 (CT70) is a 72-cc trail bike produced from 1969 to 1994. Successor to the famed Z50 Money Bike, this two-wheeler featured a Dachshund-like frame (earning it the nickname “Dax”), classic exterior, and was the 1st minibike to have a 4-speed manual transmission.

Not only is the CT70 well-loved for its retro styling, chrome fenders, and no-nonsense functionality, but it is also known as Honda’s 2nd most popular bike – next only to the CB750. These qualities, however, do not describe the note-worthy characteristics of this nostalgic pit bike enough. So, whether you are a die-hard Honda enthusiast or have recently taken a liking to vintage wheelers, read on – this guide is guaranteed to give you more details about the Honda Trail 70.

Red 1972 Honda Trail 70 Mini Bike

Honda Trail 70 History

Successor to the fondly remembered Monkey bike (a.k.a. Honda Z50 series), the Honda Trail 70 is a 72-cc minibike that is well-loved by the riding community and, more so, by avid collectors worldwide. Like the Z50, it also carried an animal moniker – it was referred to as the Dax (short for Dachshund) due to its distinct, long T-bone frame. The two-wheeler was produced from 1969 to 1982, went through an 8-year hiatus, then came back for a final hurrah from 1991 to 1994. Below is a complete list of all Honda Trail 70 models:

Year / ID Colors Engine / Transmission
1969 – 1971 CT70KO Candy Ruby Red, Candy Gold, Candy Sapphire 3-speed auto clutch, 72-cc OHC Engine
1970 – 1971 CT70HKO Candy Blue Green, Candy Emerald Green, Candy Topaz Orange 4-speed manual clutch,72-cc OHC Engine
1972 CT70K1 Candy Ruby Red, Candy Yellow Special 3-speed auto clutch, 72-cc OHC Engine
1972 CT70HK1 Candy Ruby Red, Candy Yellow Special 4-speed manual clutch,72-cc OHC Engine
1973 CT70K2 Candy Topaz Orange, Candy Riviera Blue 3-speed auto clutch, 72-cc OHC Engine
1974 CT70K3 Candy Topaz Orange, Candy Riviera Blue 3-speed auto clutch, 72-cc OHC Engine
1975 CT70K4 Mighty Green 3-speed auto clutch, 72-cc OHC Engine
1976 CT70 Tahitian Red 3-speed auto clutch, 72-cc OHC Engine
1977 CT70 Shiny Orange 3-speed auto clutch, 72-cc OHC Engine
1978 CT70 Black 3-speed auto clutch, 72-cc OHC Engine
1979 CT70 Bright Yellow 3-speed auto clutch, 72-cc OHC Engine
1980 – 1994 CT70 Tahitian Red 3-speed auto clutch, 72-cc OHC Engine

The Dax was first introduced in Canada in 1969 as the Honda ST70. Expectedly, the bike grew in popularity almost overnight, finalizing Honda‘s decision to bring the wheeler to American shores. In the U.S., the bike retained its moniker but was marketed as the Honda CT70. From its inception, the pocket bike enjoyed an 18-year production run, only halted by inflation and EPA compliance costs. These factors left its styling cut and dried, which did not impress consumers accustomed to chrome panels and candy colors.

Cost of a Honda Trail 70

Sources for a full rundown of Honda Trail 70 list prices proved challenging to find online. Conversely, the price range for secondhand CT70s starts from $1,000 and can go up to $10,000. Due to this two-wheeler’s rarity and sentimental value, pre-owned Honda Trail 70s priced between $1,600 and $2,500 are already considered a bargain. Any unit valued above $3,000 has most likely been restored or kept in perfect mint condition.

Improvements to the Trail Cub

The Honda Trail 70 underwent a total of seven (7) addendums during its entire production. Here are the most significant developments done to the classic wheeler:

  • 1970 saw the introduction of a 4-speed manual clutch HKO version with a separate headlight and speedometer.
  • The 1973 CT70K2 model had mirrors and upgraded headlight ears and rear.
  • Honda Trail 70s, a year after, came standard with turn indicators.
  • Changes to the ignition switch, speedometer, and other parts of the bike continued until 1982.
  • During its comeback in 1991, the Honda CT70 sported redesigned front shocks, white wheel rims, and a configured speedometer.
  • Honda complied with emission guidelines for’ 91-’94 models by adding an air recovery device.
  • Electrical components eventually changed from 6V to 12V, providing decent lighting and a locking fork, seat, and helmet holder.

While Honda had the best intentions in mind when making these improvements, consumers found some of them nonsensical. For example, many riders thought it was bad taste to paint the rims and hubs white (as these parts get a lot of chain oil and dirt, and painting them white only makes the bike look dirtier than it really is). Some owners disliked the Mighty Green trim, as they find purple and teal a very odd color combination. But what ultimately sealed the fate of the Dax’s comeback was Honda getting rid of high-quality parts.

Honda CT70 Mini Bike Specs and Features

Red 1972 Honda Trail 70 Bike

Engine

The Honda CT70 offers a straightforward single-cylinder engine configuration and an efficient air cooler that is comparable (if not alike) to the Honda ATC70. A minor difference between the two is their carb size – the ATC70 had a 17-mm carb while the Trail 70 started with a 16-mm and upgraded to a 20-mm carb size for later-year versions.

Bone stock, the Honda Trail 70 can reach up to 47 mph (75 km/h) – at least for post-1970 CT70 trims. On the other hand, Honda Trail 70 top speed for 100-cc converted machines can go up to 77 mph (124 km/h) or even higher, depending on the kind of mods done on the dirt bike.

Honda Trail 70 (ST70, CT70/70H) Honda Trail 70 (K1, K2, K3)
Engine Type 4-Stroke OHC
Cylinder Arrangement Single-cylinder, 80° inclined from vertical
Cylinder Compression 11.95 ± 1.0 kg/cm2 (170 psi) @ 1,000 RPM
Carburetion System Carburetion, Keihin piston-valve type x 1
Engine Cooling Air cooling
Jetting (Main, Air, Slow) ST70: #65; #150; #35
CT70/70H: #60; #150; #35
#58; #150; #35
Engine Fuel Unleaded gasoline of at least PON 87 or RON 91, containing < 5% MTBE (Methyl Tertiary Butyl Ether), < 10% ethanol, or < 5% methanol w/ appropriate cosolvents and corrosion inhibitors
Fuel Capacity 2.5 L (5.28 US pint/0.66 US gal)
Bore x Stroke Ratio 47 x 41.4 mm (1.85 x 1.63 in)
Compression Ratio 8.8:1
Displacement 72 cm³ / 4.4 in³
Valve Clearance Cold (Int/Ex) 0.05 mm (0.0020 in)
Horsepower 5 hp/5.1 PS @ 8,000 RPM
ST70: 5.6 hp/5.7 PS @ 8,000 RPM
CT70H: 4 hp/4 PS @ 8,000 RPM
CT70K2/K3: 4.5 hp @ 8,500 RPM
CT70K1: 4 hp @ 8,000 RPM
Maximum Torque 4.9 Nm (0.50 kgf-m, 3.6 ft-lb @ 5,500 RPM) ST70: 5 Nm (0.511 kgf-m, 3.7 ft-lb @ 7,000 RPM)
CT70H, CT70K1/K2/K3: 4.9 Nm (0.50 kgf-m, 3.6 ft-lb @ 4,000 RPM)
Top Speed CT70: 43 mph (70 km/h);
47 mph (75 km/h)
47 mph (75 km/h)
Air Filtration Oiled polyurethane foam type
Lubrication Forced pressure (wet sump)
Engine Oil & Quantity 0.8 L (1.7 US pint) – ST70, CT70; 0.7 L (0.74 US pint) – CT70H, CT70K1/K2/K3
SAE 10W-40 Honda 4-stroke oil w/ an API grade of SJ, JASO T903 MA, MB
Alternatives: SAE 30 (above 15° C/60° F); SAE 20W (-10° to 15° C/15°-60° F); SAE 10W (below 0° C/32° F); SAE 20W-50 (above -10° C/15° F)

If you are mechanically inclined and want more power, go for a CT70 Honda 100-cc upgrade by getting a big-bore carb rebuild kit.

Drivetrain

The majority of the 70-cc Honda mini trail bikes have conventional two-disc wet clutch assemblies. Only the CT70H and K1 to K3 versions incorporated the manual clutch. Interestingly, the ’72 CT70K1 trims have a different 1st gear but share similar 2nd and 3rd gear ratios with the’ 73-’74 models. The CT70H version has the same 1st to 4th gears as the CT70K2/K3 trims.

Upon closer inspection, many skilled mechanics say the 4th gear ratio for the CT70H has been misprinted on the manual, as it shows as 2.958 (the value does not sit right with the rest of the gearing). That said, I included the correct 4th gear below to show what would work best with the 4-speed manual tranny and 2.733 (15/41) final drive. But if you prefer 17T/35T sprockets, the following gears should go on your wheeler:

  • 1st – 3.273
  • 2nd – 1.938
  • 3rd – 1.350
  • 4th – 1.043
Honda Trail 70 (ST70, CT70/70H) Honda Trail 70 (K1, K2, K3)
Clutch Wet multi-plate, automatic, centrifugal type – ST70, CT70; Wet multi-plate, manual – CT70H/HK Wet multi-plate, manual type
Transfer, Transmission Type 3-speed constant mesh – ST70, CT70; 4-speed constant mesh – CT70H/HK1 4-speed constant mesh
Gearshift Pattern 1-N-2-3 (left-foot-operated return system) – ST70;
N-1-2-3 (left-foot-operated return system) – CT70;
N-1-2-3-4 – CT70H/HK1
N-1-2-3-4
Drive System Chain drive w/ 10-20 mm (0.040 – 0.080 in) slack
Primary Reduction Ratio 3.722 4.058 – CT70K1; 3.722 – CT70K2/K3
Final Drive Ratio 2.733 (15/41) – CT70, CT70H; 2.533 (15/38) – ST70 2.333 (15/35) – CT70K1; 3.214 (14/45) – CT70K2/K3
Transfer Gear Ratio (ST70, CT70)
1st – 3.364
2nd – 1.722
3rd – 1.190

(CT70H)
1st – 2.692
2nd – 1.824
3rd – 1.300
4th – 0.958
(CT70K1)
1st – 3.272
2nd – 1.824
3rd – 1.300 4th – 0.958
(CT70K2/K3)
1st – 2.692
2nd – 1.824
3rd – 1.300 4th – 0.958

Ignition

The 1970 Honda CT70 has a flywheel magneto ignition and an AC generator charging system. It requires a 12V 3/4Ah battery and an NGK C7HS spark plug. NGK C7HS plugs have at least 19 replacements, while NGK C6HS plugs that went on the ’69 models have these three – Bosch 0241045001, Bosch U5AC, or Bosch U6AC.

For more convenient searching, sites like Brisk USA have a spark plug finder that makes it easy to determine the appropriate replacement for your minibike. Just make sure to check with your local mechanic or auto shop on the compatibility of these plugs with your trail bike before usage. Also, remember to change the stock or existing spark plug of your trail bike to NGK C9H/Nippon Denso U24FB (or its equivalent) should you choose to subject your wheeler to extended high-speed operation.

Honda Trail 70 (ST70, CT70/70H) Honda Trail 70 (K1, K2, K3)
Ignition Flywheel magneto
Ignition Timing 25° B.T.D.C. @ 1,200 – 1,300 ± 100 RPM (constant)
Idle Speed 1,200 RPM ± 100; 1,300 RPM ± 100 – CT70H 1,200 RPM ± 100
Starter System Forward kick-start mechanism
Spark Plug ST70: NGK C6HS or ND U24FS
CT70: NGK C7HS or ND U24FS
CT70H: NGK C7HS or ND U22FS
Gap: 0.6-0.7 mm (0.024 – 0.028 in)
NGK C7HS or NIPPON DENSO V22FS
Gap: 0.6-0.7 mm (0.024 – 0.028 in)
Generator Flywheel A.C. generator
Fuse 7 Amp (main)
Battery 6V (2 Ah)/10 HR, Yuasa 6N2A-2C / 6N4C-1B / YTX4L-BS formats
Battery Dimensions (L x W x H) 6N2A-2C/2C-3 (’69-’73): 70 x 47 x 106 mm (2.75 x 1.88 x 4.19 in)
6N4C-1B (’74-’82): 71 x 71 x 105 mm (2.81 x 2.81 x 4.12 in)
YT4L-BS (’91-’94): 114 x 71 x 86 mm (4.50 x 2.81 x 3.38 in)

As for the battery, the service manual specifies a Yuasa B60-6 format for the mini trail bike (which has been long discontinued). Should you need to swap out the stock battery of your two-wheeler, you can choose from any of the options above – although I would personally recommend going for the YTX4L-BS battery (view on Amazon) format so as not to have trouble looking for a replacement.

Tires & Brakes

Honda Trail 70 (ST70, CT70/70H) Honda Trail 70 (K1, K2, K3)
Wheel Composition Steel, laced wire spokes, Cast aluminum Cast aluminum
Front Tire, off-road/road air pressure 4×10 (2 PR) Bridgestone Trailwings, 107.5 – 127.5 kPa (1.1 – 1.3 kgf/cm2, 15.6 – 18.5 psi);
3×10 (2 PR) Bridgestone Trailwings, 97.9 kPa (1.0 kgf/cm2, 14.2 psi) – ST70, CT70H
4.00 x 10 (2 PR) Bridgestone Trailwings, 117.2 kPa (1.2 kgf/cm2, 17 psi)
Rear Tire, off-road/road air pressure 4×10 (2 PR) Bridgestone Trailwings, 127.5 – 146.9 kPa (1.3 – 1.5 kgf/cm2, 18.5 – 21.3 psi);
3×10 (2 PR) Bridgestone Trailwings, 117.2 kPa (1.2 kgf/cm2, 17 psi) – ST70, CT70H
4×10 (2 PR) Bridgestone Trailwings, 137.9 kPa (1.4 kgf/cm2, 20 psi)
Rim Size (F/R) 2.75 x 10
Tire Tread Limit 3 mm (0.11811 in)
Front Brake Type Internal expanding shoe, 110 mm
Rear Brake Type

Otherwise known as a 130 x 90/10 tire (view on Amazon) size, the original rubber on the Honda Trail CT70 70 series is rare and was used on only one other classic bike – the Honda Z50. Pirelli and other popular brands are still known to manufacture this tire. So, if you ever have tough luck purchasing this pair of knobbies, stock wheels on a Z50 should be your next best option.

Suspension

The CT70 minibike initially had a telescopic fork as its front suspension. It changed to Earles fork for 1971 Honda CT70 70-cc machines and later-year CT70 models. This leading link fork suspension lends to the bike’s ability to climb over bumps and obstacles effortlessly. Compared to telescopic forks, this suspension system looks heavier but actually weighs lighter.

Honda Trail 70 (ST70, CT70/70H) Honda Trail 70 (K1, K2, K3)
Frame T-bone type Steel pressing
Caster, Trail 65°, 58 mm (2.3 in) 63°, 70 mm (2.7 in) – CT70 K1/K3
63°, 71 mm (2.8 in) – CT70 K2
Turning Radius 1.6 m (5.2 ft)
Ground Clearance 180 mm (7.1 in)
165 mm (6.5 in) – ST70, CT70H
190 mm (7.5 in)
Front Suspension Type, Travel Telescopic fork, 50 mm (1.96 in)
Rear Suspension Type, Travel Swingarm, 64 mm (2.52 in)

Dimensions

Except for the seat height and payload capacity of the Honda Trail 70, everything else about its dimensions seems to have been upgraded for later-year models. The most noticeable of these changes is the jump in curb weight.

Honda Trail 70 (ST70, CT70/70H) Honda Trail 70 (K1, K2, K3)
Length 1,510 mm (59.8 in) 1,515 mm (59.6 in)
Width 580 mm (22.8 in) 660 mm (26 in)
Height 960 mm (37.8 in) 1,010 mm (39.8 in)
Seat Height (Unloaded) 745 mm (29.3 in)
Wheelbase 1,035 mm (40.7 in) 1,050 mm (41.3 in)
Curb Weight 62 Kg (136.7 lbs)
65 Kg (143.3 lbs) – ST70, CT70H
73 Kg (161 lbs)
Vehicle Load Capacity Limit 100 Kg (220 lbs)

Exterior

A couple of trademark features define the Honda Trail 70 – its foldable handlebars and Dachshund-like T-bone frame. They not only make the minibike stand out but also lend to its portability. Not to mention the stout frame and handlebars – along with the circular headlight and candy-based body color – go very well with other Honda CT70 parts and give the wheeler its overall classic look.

From Play Bike to Street-Legal 

Despite its size, the potential of the Honda Trail 70 is massive – making it many an off-roader’s favorite project build. That said, here are a few reminders on how to get your wheeler road-legal in no time:

License Plate

Along with the title, vehicle registration with tax, and a valid driver’s license (with a two-wheeled vehicle endorsement), this is one of the requirements to use your wheeler on public roads. There are tons of aftermarket license plate kits like Mr. Car Tool License Plate Holder (view on Amazon) that allow you to conveniently hinge the license plate to the rear-end of your bike’s frame under the stock taillight. Or you can customize your own if you feel the license plate is obstructed from view.

Lighting

Check your specific state laws if you only need one or separate brake light and taillight for your minibike. As for headlights, there may be a need for a new stator to power it up, along with turn signals, brake lights, and taillights. Your choice of headlight – halogen, LED, or HID – does not matter. But make sure to go for one with a high-low beam function.

Safety Equipment

Apart from lighting and license plate, your Honda Trail 70 would also need to have at least one rearview mirror (mounted on the left side of the handlebars), a horn, a hand or foot brake, and footrests (for models with passenger seating). Wearing a helmet is mandatory for operators and passengers below 18 years old or those operating with an instruction permit. Additionally, riders must wear eye protection.

DOT-approved Tires

Depending on the application of your minibike, you can opt for either knobby tires with an optimized tread (great for dirt tracks and gravel) or aggressive tread with firmer side knobs and larger central blocks (perfect for asphalt roads and rough surfaces). You can tell that a pair of rubber is DOT-approved via the letters “DOT” seen on the tire sidewall.

Muffler

Getting a muffler or silencer cap not only enables your Trail 70 to pass smog/emissions testing but also helps it meet sound restrictions. While most U.S. states set the noise limit within 82-86 dB, some states like Massachusetts do not provide any specific figure (so long as the new exhaust system does not cause the bike to be louder than when it was stock).

Engine Upgrade (Optional)

Most owners who register their bikes to be road-legal convert their Honda Mini Trail 70 from having a 72-cc power mill into a 150-class machine by equipping it with a 140-cc YX140 engine and a 26-mm Mikuni carburetor. This not only improves the minibike’s performance but also increases its top speed to at least 50 mph (80 km/h).

Regardless if you are registering a 1970 Honda Trail 70 300-cc bike or a Honda CT70 clone to be street-legal, do not forget to have liability insurance for your wheeler. Having this is not only required but also a lifesaver in the event of unforeseen emergencies – like crashing headfirst into your neighbor’s fence. Not that you will ever want that to happen. But hey – you can never be too prepared.

About Honda

The Honda Motor Company Ltd. is globally recognized as one of the pioneers of the ATV and motorcycle industries and is the maker of the Honda Trail 70 and CT series. Founded in 1946 by Soichiro Honda, the company has evolved from mass-producing piston rings to becoming one of today’s world leaders in the automotive industry. At present, Honda continues to uphold its legacy through its armada of product offerings, including high-caliber automobiles, power equipment, and multipurpose engines.

Conclusion – Honda Trail 70 Mini Bike Review

The times may have caught on the Honda Trail 70 minibike. But for its small but loyal following, this classic will forever be timeless and hold a special place in their hearts and their garage. For people who truly see its unprecedented nature, the two-wheeler continues to be a symbol of the golden era of pocket bikes. A vehicle that can withstand abuse and extended periods of trail riding fun, the Honda CT70 continues to be a testament to off-roading bliss and good times.

Kris Peter

Adventure seeker and off-road enthusiast. I love the thrill of going off-road and taking on the elements.

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