Suzuki TS125 Dual-Sport Dirt Bike: History, Specs, & Review

The Suzuki TS125 stands as an enduring icon in the realm of dual-sport dirt bikes, carving a niche for itself in the early ’70s with a blend of versatility and rugged performance. As such, this article delves into the rich history, technical specifications, and a comprehensive review of this trailblazing two-wheeler, exploring its evolution and enduring appeal among riders.

Produced from 1970 to 1992, the Suzuki TS125 marked Suzuki’s entry into the dual-sport arena. Boasting a 5-speed manual gearbox, a down-swept exhaust, and an industry-leading Suzuki CCI system, the TS125 quickly became the go-to option for both on- and off-road adventures.

The TS125’s strengths lie in its adaptability, making it a formidable contender for both on-road commuting and off-road escapades. The dual-sport nature of the bike, complemented by its other praiseworthy attributes, provides riders with a versatile and enjoyable experience. Curious as to what gives the TS125 this renowned reputation? Read on – this guide has got you covered.

The Suzuki TS125 History

The Suzuki TS125 hails from the Japanese manufacturer’s TS series — a lineup of dual-sport 2-stroke machines with a displacement range of 50cc to 400cc. Known as the TS 125 Hustler in Japan from 1981 to 1992, the bike adopted the moniker Duster in North American markets. During the mid to late ’80s, alternative designations like TS125X, TS125RK, and J Duster were used, as reflected in various online sources.

Debuting in December 1970 for the Japanese market, the TS125 marked Suzuki’s foray into the dual-sport domain. Equipped with 13 bhp, a five-speed transmission, and a distinctive high-drawn exhaust pipe, it showcased both design distinction and formidable performance. Complementing the TS125 was its counterpart, the TC-125. It featured a dual-range 8-speed gearbox, a luggage rack (view on Amazon), and an elevated front mudguard and was known as the Prospector in the US.

Renowned for its versatility, the Suzuki TS125 was described as “a little runaround that you could take off-road” that provided riders with a reliable and nimble option for various riding conditions. Its manufacture spanned from 1970 to 1992, marked by the designation TS125ER between 1980 and 1987.

Throughout its production years, the Suzuki TS125 underwent several iterations, reflecting Suzuki’s commitment to refining and enhancing the bike’s performance and features. With its enduring presence in North American markets, the Duster remains large in the used-bike scene and the dual-sport motorcycle landscape.

Suzuki TS125 Specs & Features

Engine

The Suzuki TS125 features an air-cooled, 2-stroke engine with a sleeved aluminum cylinder, piston-ported intake system, and PRI kickstarter. It has a 123 cm³ (7.5 in³) piston displacement, a 6.7:1 compression ratio, and an almost-square 56 x 50 mm (2.205 x 1.969 inches) bore-stroke ratio (shared with the 1975 Suzuki RM 125).

The primary kickstarter allows the mill to be fired up in gear and neutral. Meanwhile, a Mikuni VM24SH carburetor with a main jet of #125 in North America (#120 all other exports) and a pilot jet of #25 — mated to a resin-processed paper filter — is responsible for managing air-fuel mixture.

Layout-wise, the engine has the typical single-cylinder configuration common in small-displacement dirt bikes back in the day. Overall, this configuration yields the following performance figures:

Description	Performance Figure
Top Speed*	65—70 mph (105—112 km/h, as advertised)
Horsepower	13 hp (9.7 kW) @ 7,000 RPM to 22 hp by 1991; 9.5 hp (7.1 kW) for West German models
Maximum Torque	12.7 Nm (1.3 kgf-m, 9.4 lb-ft) @ 7,000 RPM; increased to 18.6 Nm (1.9 kgf-m, 13.7 lb-ft) @ 7,500 RPM for 6-speed models
Fuel Economy	67 mpg (3.5 L/100 km, 28.5 kmpl, fuelly)
Approximate Tank Range	approximately 124 miles, 199.5 km

Fuel & Lubrication

The fuel tank’s capacity is approximately 7 L (1.8 USgal) of unleaded gasoline, including a 1.5-L/1.6 US quart reserve. This is 2.5 L shy of the tank capacity of the dirt bike’s debut model.

All production trims require fuel with a minimum Octane rating of 87 PON. For units sold in Europe, compatibility extends to E10 fuels or those containing up to 10% ethanol. As customary of most 2-strokes, it’s best to steer clear of gasohols featuring unspecified MTBE (Methyl Tert-Butyl Ether) and those with methanol content.

Lubrication-wise, the TS125 has the following requirements:

• 1.1 L (1.2 US qt, 1.0 Imp qt)
• 0.55 L (0.58 US qt, 0.49 Imp qt, gearbox)
• 700 ml (0.74 US qt, 0.61 lmp qt, transmission oil)

Recommended lubrication is SAE 10W-40 of synthetic 2-stroke motorcycle oil with an API grade of SJ or higher, meeting JASO T903 MA/ACEA/DIN standards. It’s crucial to avoid oils labeled as “Energy Conserving” or “Resource Conserving” for the TS125. Other oil viscosities outlined in the manual are permissible, following variations in ambient temperatures, altitude, and riding conditions.

Suzki CCI (Crankcase-Cylinder Injection)

Suzuki CCI is a unique posi force oiling system that pressure-delivers oil used to lubricate engine stressed points from the dirt bike’s variable displacement oil pump. This revolutionary lubrication system eliminated the need for premixing, standard in 2-strokes in the ’70s.

Although the lubrication system has been adopted for the Suzuki TS125, it’s still recommended to address carbon deposits in the combustion chamber every 6,000 km or 4,000 miles. A screwdriver or appropriate bit is advisable for this maintenance, with caution to avoid damaging the dome surface. The same tool can be used to clean dirt from the cylinder head alongside a brush with cleaning solvent or gasoline.

Drivetrain

Power is transferred to the rear wheel through a 5-speed, constant-mesh, return-shifting type transmission (upgraded to 6-speed for later iterations). It also mates to a multi-plate wet clutch assembly. Meanwhile, a DAIDO #428D chain with 116 links and a single chain link handles the wheelspin, which is replaceable with an RK Racing Chain M428H-116, 428 Series (view on Amazon).

The gearbox comprises a countershaft, drive shaft, and gears mounted on the shaft. The Suzuki TS125 transmission is designed to facilitate the flow of transmission oil through the oil passage of the bushing, ensuring effective lubrication.

Here are the stock transmission gear ratios of the TS125 (for its 5-speed and 6-speed configurations):

Description	1977 TS125	1982 TS125ER
Primary Reduction Ratio	3.562 (57/16)	3.562 (57/16)
Transmission Gear Ratio — Low	32.65:1	3.090 (34/11)
Transmission Gear Ratio — 2nd	21.51:1	2.000 (30/15)
Transmission Gear Ratio — 3rd	14.84:1	1.368 (26/19)
Transmission Gear Ratio — 4th	11.87:1	1.095 (23/21)
Transmission Gear Ratio — 5th	9.50:1	0.956 (22/23)
Transmission Gear Ratio — 6th	N/A	0.840 (21/25)
Final Reduction Ratio	3.333 (50/15T)	3.066 (46/15T)
Oil Pump Reduction Ratio*	6.13:1 (57/16 x 31/18)	N/A

Ignition & Electricals

The dirt bike’s initial version had a conventional points-based or contact breaker point system for ignition. Ignition timing was set to 21-23° (2.20-2.62 mm, standard) and 24-26° (2.85-3.33 mm, full advanced) BTDC @ 6,000 RPM. Post-1980 incarnations of the bike were given a CDI (Capacitor Discharge Ignition) system.

An NGK B-77HC/B-7HS (view on Amazon) or Nippon Denso W22FS/W24FS spark plug is responsible for spark ignition. Meanwhile, a Nippon Denso AMLC-04 Flywheel Magneto with a lighting performance of V @ 2,500 RPM and below 9V @ 8,000 RPM serves as the two-wheeler’s charging system. The electrode gap isn’t specified in the manual. However, alternative spark plug variants are suggested — the use of which is contingent on hot or cold heat ranges.

An interesting aspect of the Suzuki TS125 was its ability to run without the battery. Nonetheless, a lead plate three-cell 6V 14.4kC 4Ah/(10 HR) battery was fitted in the frame’s central section to power the horn, headlight, tail light & directionals.

For improved lighting or upgrading the motorcycle’s battery and charging system, you may consider converting the electrical system to 12V with a conversion kit. Once modded, the dirt bike’s electrical system should be compatible with a 12V 6 Ah/(10 HR) Maintenance-free, YTX7L-BS format.

Tires & Brakes

Stock tires are 2.75-19 4PR/2.75-21 4PR (front) and 3.25-18 4PR/4.10-18 4PR tubed knobbies on spoked cast aluminum rims. If you encounter tire issues, you can replace them with similar-spec options like the Bridgestone Battlax Adventurecross AX41 (view on Amazon) for the front tire. Conversely, retighten spokes using a spoke nipple wrench every 3,000 km (1,900 miles) to prevent wheel deformity. Completing the tire-and-wheel assembly of the TS125 are internal-expanding (hand-and-foot-operated) drums.

Suspension

The 1977 version of the Suzuki TS125 had a single-downtube, double-cradle frame, and featured telescopic front forks and rear shocks, both hydraulically-damped and offering 3-way and 5-way adjustability, respectively. Wheel travel isn’t specified in the service manual but can be assumed at approximately 107 mm (4.2 inches) to 130 mm (5.1 inches), if not close to these specs.

These suspension units were designed to cater to diverse riding conditions, accommodating both on-road and off-road situations. Meanwhile, other elements contributing to the dual-sport’s adept handling are its 1,310 mm (51.6 inches) wheelbase, 235 mm (9.2 inches) minimum ground clearance, and 2.4 meters (7.9 feet) turning radius.

Dimensions & Capacities

The two-wheeler’s dimensions measure 2,050 x 845 x 1,100 mm (80.7 x 33.3 x 43.3 inches — L x W x H). Seat height for earlier iterations of the dirt bike isn’t specified in the manual, although online sources like Suzuki Cycles mention the saddle being 860 mm (33.9 inches) for the 1990 version.

Regarding capacity, the TS125’s dry weight varies between 90 and 110 kg (198 to 242.5 lbs., unladen), contingent on its model year. Simultaneously, its presumed maximum weight capacity is around 131 kg (289 lbs.). Factoring in these figures, the TS125’s GVWR (Gross Vehicle Weight Rating) can be approximated at 236—256 Kg (520—564 lbs.) — encompassing passenger/rider weights, a full fuel tank and fluids, cargo, and accessories.

Exterior

The Suzuki TS125’s dual-sport nature is evident in the combination of off-road features like high-clearance fenders and knobby tires with road-ready elements such as a streamlined fuel tank and compact frame. The dirt bike’s ergonomic layout, with a comfortable yet agile stance, reflects a balance between functionality and style and has remained largely consistent throughout production models — with the occasional passenger footpegs (view on Amazon) and racy, aggressive decals in some models.

If anything, the most outstanding facets of the two-wheeler’s styling are its dominant tail section, polished front forks, and down-swept exhaust system. Subsequent models had the exhaust cleverly positioned further beneath the rear seat, enhancing clearance for negotiating obstacles like logs and rock ledges without risking contact with the exhaust bottom.

Suzuki TS125-T

The Suzuki TS125T, designed as a street sports variant, featured distinct graphics and a closely fitting front mudguard. It also had a slightly narrower profile and heftier mass than the Enduro-styled TS125. Suspension-wise, the TS125T boasted 3-way adjustable front forks and 5-way adjustable rear shocks. Nonetheless, it looked more like a slim brat bike with very little frills — not to be confused with the TC125 Prospector, a separate model released in the US.

How Much Is a Suzuki TS125?

Finding online information about the MSRPs for Suzuki TS125 models from the ’70s can be difficult. But based on owner feedback on TS125-dedicated forums and Cycle World Magazine’s reviews, the dirt bike sold for $579 in 1973. JD Power affirms this, citing a 1981 TS125R for $1,079 (approximately $3,653.51 with inflation factored in).

Low to average retail pricing from the same resource lists the bike’s value from $450 to $3,060. On the other hand, auction listings sell secondhand TS125s for as much as ¥798,000 starting price. It’s unclear when Suzuki ceased production of this dirt bike lineup. Nonetheless, the two-wheeler is cited to have sold brand-new for ¥318,000—¥349,000 between 1990 and 1991 in Japan.

Suzuki TS 125 — Highs and Lows

Although the Suzuki TS125 holds a revered status as a classic and is a formidable option in the realm of dirt bikes, it’s not impervious to imperfections. That said, delving into the lowdowns of the TS125 becomes essential, especially if contemplating on it as your next dual-sport purchase:

Pros

• By directly supplying fresh oil to critical components, Suzuki’s CCI system effectively doubled the engine’s lifespan.
• Also, the minimal oil consumption in this process resulted in reduced carbon buildup and production of cloudy exhaust fumes.
• Post-1979 models received a 6-speed gearbox and then-new reed valve engine, improving the dirt bike’s handling and power delivery.
• The dirt bike’s rear swingarm was upgraded to an aluminum variant in 1981. The year after, the Full Floater swingarm was made standard.
• Liquid cooling was introduced in 1984. Similarly, front disc brakes were conventionalized in all production models in 1988.
• Power and torque outputs were increased to 22.3 hp (16.5 kW) @ 8,000 RPM and 19.6 Nm (2.0 kg-m) @ 7,500 RPM in the late ’80s.
• Fuel tank capacity for later-year iterations was restored to 9 L, lending to a generous 138 mpg (1.7 L/100 km, 58.8 kmpl) fuel mileage.
• Japanese releases featured a 2-up layout and a slightly longer and wider profile than their North American counterparts.

Cons

• The dirt bike’s short wheelbase, high center of gravity, and small tires can pose challenges, particularly in sliding turns.
• Similarly, front-end instability on sand surfaces increases the likelihood of the bike washing out during turns attempted at speed.
• Rear traction problems cause the bike to whip out when losing grip, lacking the power needed for a controlled slide.
• The bike isn’t ideal for desert use due to small tires.
• Suspension issues on rocky surfaces, especially with rear shocks losing effectiveness when heated, lead to an unstable ride and wheel chatter during hard braking.
• Despite improved front forks, the rear shocks still had a tendency to bottom out with a 160-lb rider, requiring adjustments for different rider weights.
• While durable, the Duster’s appearance as a racer might not match its actual vulnerabilities, like potential bent wheel rims.
• Rough welds on the frame may affect aesthetics despite being well-triangulated with a single top tube and downtube.
• The engine is cradled by the unit, but protection from rocks depends solely on a small bash plate covering the center engine cases.
• Post-1990 Japanese units were 20 Kg heavier than the original ’70s version.

About Suzuki

Established in 1909, Suzuki Motor Corporation didn’t initially venture into the automotive industry but embarked on its journey through loom weaving in Hamamatsu. It wasn’t until 1937 that the creator of the Suzuki TS125 dirt bike contemplated diversification and entered the realm of small car manufacturing. Completing its first car project in 1935 marked a pivotal moment in Suzuki’s history.

Evolving from prototype cars, Suzuki transitioned to mass-producing motor vehicles, motorcycles, and gas-powered engines. Pioneering the rack-and-pinion steering system showcased the company’s innovation. Suzuki is a global powerhouse producing motorcycles, 4WD vehicles, and internal combustion engines, boasting over 68,499 employees and 133 distributors in 92 countries.

Conclusion — Suzuki TS125 Specs & Review

Without a doubt, the Suzuki TS125 has left an indelible mark on the motorcycle landscape. From its early years as a trailblazer in the ’70s to its evolution into the TS 125 Hustler and Duster, it has consistently embodied Suzuki’s commitment to innovation and rider satisfaction. Thanks to its rich history and simplified but robust specifications, the TS125 remains a beloved choice for riders seeking a versatile and enduring dual-sport experience while navigating city streets or conquering off-road trails.