Sun Coast Cycle Sports stocks inspected used parts for the 1997-2004 Triumph Speed Triple 955i, the streetfighter that defined the modern super-naked category. Starting as the T509 (885cc) in 1997 and growing to 955cc for 1999, the Speed Triple paired the Daytona's inline triple engine with flat handlebars, a single-sided swingarm, and the iconic bug-eye dual headlights. Each component from our Speed Triple donors is evaluated at our Florida facility, photographed under a unique SKU, and shipped free across the continental United States.
Speed Triple 955i generation and parts compatibility
| Years | Designation | Engine | Power | Key Changes |
|---|
| 1997-1998 | T509 Speed Triple | 885cc DOHC liquid-cooled triple | 108 hp | First-gen: polished frame (97), higher bars (98); Sagem EFI |
| 1999-2001 | Speed Triple 955i | 955cc DOHC liquid-cooled triple | 110 hp | Renamed 955i; bore increase; improved wiring harness (2000+) |
| 2002-2004 | Speed Triple 955i | 955cc DOHC liquid-cooled triple | 118 hp | Redesigned bodywork, lighter engine cases (-17 lbs), O2 sensor, revised seat unit |
The Speed Triple 955i shares its engine directly with the Daytona 955i sportbike. Engine internals (crank, pistons, cylinders, gearbox, clutch) interchange between the two models, though the Speed Triple uses detuned cam timing and ECU mapping for more midrange torque. The aluminum trellis frame, single-sided swingarm, and Showa suspension are shared between both models. The Speed Triple's unique components are its flat handlebars, dual round headlights, upright subframe/seat unit, and model-specific exhaust routing.
All Speed Triple frames from 1997 through 2008 share the same engine mounting pattern. The 885cc T509, 955i, and later 1050 engines all bolt into frames from this era, though the 1050 requires minor modifications. The subframes, triple clamps, and swingarms are also interchangeable across 1997-2008 models with year-specific variations in welds and mounting tabs.
The 955cc engine is a different family from the earlier 885cc Thunderbird/Trophy triple and the later 675cc Daytona/Street Triple engine. No parts interchange between these engine families.
Common Speed Triple 955i failure points and replacement parts
Regulator/rectifier failure: The stock R/R is a well-documented weak point across all 955i-era Triumphs. Overcharging boils batteries; undercharging leaves the bike stranded. Aftermarket MOSFET replacements with improved heat management are strongly recommended as a preventive upgrade.
Wiring harness ground block failure (1997-1999): The early T509 and first-year 955i models used a ground block that is prone to corrosion and failure, causing intermittent electrical problems. The 2000+ models received an improved wiring harness that addressed this issue. Retrofitting the updated harness or repairing the ground connections is a common fix on earlier bikes.
Gearbox notchiness: The Speed Triple's gearbox can develop a notchy feel, particularly between first and second gear. Firm, deliberate shifts are required to avoid false neutrals. Regular gearbox oil changes with the correct specification oil minimize the issue.
Starter clutch sprag wear: The one-way starter clutch sprag can develop wear, causing intermittent failure to engage the starter. A whirring noise during cranking that does not turn the engine over is the telltale symptom.
Fuel injection mapping (pre-2002): Early 955i models can exhibit hesitation and flat spots at part throttle due to fuel injection mapping. The 2002+ ECU with O2 sensor feedback significantly improved fueling.
Commonly replaced Speed Triple 955i parts
- Regulator/rectifier
- Wiring harness or ground block repair (1997-1999)
- Starter clutch sprag assembly
- Dual headlight assembly
- Exhaust system and headers
- Chain and sprocket kit
- Fork seals and cartridge service
- Single-sided swingarm bearings
Frequently asked questions
Q: Will Daytona 955i engine parts fit my Speed Triple?
Yes. The Speed Triple 955i and Daytona 955i share identical engine internals. Crankshaft, pistons, cylinders, gearbox, clutch, and oil pump interchange directly. The Daytona uses a higher-power tune, but the hard parts are the same. The Daytona 955i is an excellent donor source for Speed Triple engine components.
Q: Can I install a 1050 engine in my 955i Speed Triple frame?
The engine mounting pattern is shared across 1997-2008 Speed Triple frames. A 1050 engine will physically bolt in, though it requires matching the ECU, wiring harness, and exhaust to the 1050 engine. This is a documented swap in the Triumph community, as it provides a significant performance increase using the same basic chassis.
Q: What changed between the T509 (885cc) and the 955i?
The T509 designation was used for 1997-1998 models with the 885cc engine. The bore was increased to create the 955cc displacement for 1999, and the model was renamed Speed Triple 955i. The chassis, frame, and suspension are shared between the T509 and 955i. The displacement change means cylinders and pistons are specific to each version, but gearbox, clutch, and most external components interchange.
Inspected by Powersports Technicians • Only One in Stock • Ships Fast from Florida
