Segment:
Entry-level youth dirt bike, popular for trail riding and recreational use.
Competitors:
Honda CRF70F, Kawasaki KLX110 (though slightly larger).
Features:
Electric start, reliable four-stroke engine, durable chassis, adjustable suspension.
Audience:
Young riders, parents of young riders, beginner mechanics.
Engine:
Top-end rebuild, bottom-end inspection, valve adjustment, carburetor tuning, ignition system diagnostics
Transmission:
Clutch service, gear inspection, shift mechanism troubleshooting
Chassis:
Frame inspection, suspension overhaul (forks and rear shock), steering bearing maintenance
Brakes:
Front and rear brake system inspection, pad replacement, fluid bleeding, caliper service
Electrical:
Wiring diagrams, lighting system troubleshooting, CDI unit testing, battery maintenance
Fuel System:
Fuel tank inspection, petcock service, fuel line replacement
Exhaust System:
Muffler and header pipe inspection, gasket replacement
Cooling System:
Air-cooled system, heat dissipation principles
Maintenance:
Oil change intervals, air filter cleaning, spark plug replacement, chain adjustment, pre-ride inspections
Repair:
Engine assembly/disassembly, carburetor rebuilding, fork seal replacement, bearing repacking
Troubleshooting:
Diagnostic charts for common starting and running issues, electrical faults
Specifications:
Torque values for all fasteners, engine timing marks, clearance specifications
Depth:
From basic owner upkeep to complete engine and chassis overhauls, suitable for DIY mechanics and professional technicians.
Type:
Four-stroke, SOHC, 2-valve
Bore X Stroke:
50.0 mm x 45.2 mm
Cooling System:
Forced air-cooled
Horsepower:
Approx. 7.3 HP @ 8000 RPM (Estimates vary by source)
Torque:
Approx. 7.0 Nm @ 6500 RPM (Estimates vary by source)
Carburetor:
Mikuni VM17 (or similar specific to model year)
Fuel Type:
Unleaded gasoline
Ignition System:
CDI (Capacitor Discharge Ignition)
Oil Type:
Yamalube 4 (or equivalent API SG, SAE 10W-30 motorcycle oil)
Crash Safety:
N/A (Off-road motorcycle, designed for controlled environments, no official road safety ratings apply).
Features:
Engine kill switch, handlebar guards (optional/standard on some trims).
Features:
Sturdy frame construction, appropriate rider ergonomics for stability.
Oil Change:
Every 1000 km (600 miles) or 6 months, whichever comes first. More frequently with hard use.
Air Filter:
Clean every 500 km (300 miles) or as needed, replace as needed.
Spark Plug:
Inspect every 1000 km (600 miles), replace as needed.
Valve Clearance:
Inspect every 4000 km (2400 miles) or 24 months.
Chain Adjustment:
Every 500 km (300 miles) or as needed. Lubricate regularly.
Engine Oil Capacity:
0.8 L (0.85 US qt)
Brake Fluid:
DOT 3 or DOT 4 hydraulic brake fluid (for disc brakes if applicable, but TT-R90 typically has drums).
Common Problems:
Carburetor clogging due to infrequent use, worn clutch plates, occasional electrical connection issues.
Maintenance Tip:
Regularly run the engine to prevent carburetor gumming. Clean and lube the chain and sprockets diligently.
Heritage:
Yamaha has a long-standing reputation for producing reliable and performance-oriented motorcycles across various disciplines, including off-road.
Evolution:
The TT-R line replaced earlier YZ-F models and was designed as a more accessible, user-friendly off-road machine for younger riders. The TT-R90 was part of this evolution, offering a step up from smaller pit bikes but remaining manageable for novices.
Production Years:
The TT-R90 was produced roughly from 2000 to 2007, with minor updates between model years.
