Category:
Entry-level off-road/trail motorcycle.
Target Audience:
Beginner riders, youth riders, recreational trail riders.
Key Competitors:
Honda CRF70F, Kawasaki KLX110 (though slightly larger displacement), Suzuki DR-Z70 (later models).
Ease Of Use:
Designed for simplicity and ease of operation for novice riders.
Durability:
Yamaha's reputation for robust construction and reliability.
Manual Value:
Essential resource for maintaining optimal performance and longevity, facilitating cost-effective repairs.
Primary Focus:
Service, Repair, Workshop
Scope:
Comprehensive maintenance, repair, troubleshooting, and diagnostics.
Estimated Pages:
300-500 (typical for full service manuals of this type)
Type:
Service Repair Workshop Manual
Format:
Digital (likely PDF, based on common sales practices)
Engine Management:
Detailed engine disassembly, assembly, timing, carburetor tuning, ignition system diagnostics.
Fuel System:
Carburetor specifications, cleaning, adjustments, fuel tank, fuel lines.
Drivetrain:
Clutch operation, transmission disassembly and assembly, gear ratios, final drive.
Suspension:
Front fork service, rear shock absorber inspection and replacement, spring rates.
Brakes:
Drum brake inspection and adjustment, brake lever and cable maintenance.
Electrical System:
Wiring diagrams, lighting system, ignition coil, stator, battery maintenance, troubleshooting.
Chassis Frame:
Frame inspection, steering head bearing maintenance, swingarm service.
Wheels Tires:
Spoke wheel tensioning, tire pressure specifications, wheel bearing service.
Preventative Maintenance:
Oil change intervals, air filter cleaning, spark plug replacement, chain lubrication and adjustment.
Troubleshooting:
Detailed diagnostic charts for common problems and symptoms.
Repair Operations:
Step-by-step instructions for major component repairs and replacements.
Adjustments:
Carburetor idle speed, clutch free play, brake lever travel, chain tension.
Rebuilds:
Engine top-end and bottom-end rebuild procedures.
Depth:
Expert Level: Covers complete disassembly, inspection, measurement, and reassembly of all major components, including detailed torque specifications and tolerances.
Engine Type:
4-stroke, SOHC, Air-cooled
Bore X Stroke:
50.0 mm x 45.2 mm
Compression Ratio:
9.5:1 (typical for this era and engine)
Horsepower:
Approx. 7-8 HP (estimate based on displacement and class)
Torque:
Not typically published for this class, but focused on low-end grunt.
Fuel Type:
Unleaded gasoline
Ignition System:
CDI (Capacitor Discharge Ignition)
Oil Type:
Yamalube 4 (or equivalent SAE 10W-30 API SG or higher)
Oil Capacity:
0.80 L (800 ml)
Transmission Type:
Automatic (Semi-automatic / Constant Mesh)
Gear Selection:
4-speed, constant mesh, with automatic clutch
Clutch Type:
Wet, multi-plate, automatic
Gear Ratios:
Specific ratios detailed in manual (e.g., 1st: 2.833, 2nd: 1.875, 3rd: 1.333, 4th: 1.000)
Safety Classification:
Off-road motorcycle, not intended for road use. Safety is paramount through design and rider education.
Braking System:
Front drum brake, Rear drum brake.
Throttle Limiter:
Often incorporates a throttle stop screw for controlled acceleration, detailed in manual.
Frame Construction:
Steel semi-double cradle frame for rigidity and impact absorption.
Impact ABSorption:
Suspension components designed to absorb trail impacts.
Engine Oil Change:
Every 1000 km (600 miles) or 6 months.
Air Filter Cleaning:
Every 20 hours of operation or monthly.
Spark Plug Check:
Every 1000 km (600 miles) or 6 months.
Chain Tension Adjustment:
Every 500 km (300 miles) or after extensive use.
Engine Oil Specification:
Yamalube 4 (or SAE 10W-30 API SG or higher)
Brake Fluid:
Not applicable (drum brakes, requires inspection and adjustment, no fluid to replace).
Carburetor Clogging:
Common in small displacement engines, especially with infrequent use or poor fuel quality. Manual provides cleaning and tuning procedures.
Chain Wear:
Regular lubrication and adjustment are crucial to prevent premature wear and ensure smooth power delivery.
Throttle Cable Adjustment:
Can become stretched over time, affecting throttle response. Manual details adjustment procedures.
Suspension Seals:
Fork seals can wear, leading to oil leaks. Manual details seal replacement procedures.
Yamaha Legacy:
Yamaha Motor Corporation, established in 1955, has a long and distinguished history in motorcycle manufacturing, known for innovation and performance across various disciplines.
Ttr Series:
The TTR line represents Yamaha's commitment to accessible, fun, and reliable off-road motorcycles for younger and less experienced riders, evolving from earlier minibike designs.
Ttr90 Introduction:
Introduced as a successor or complement to smaller Yamaha off-road models, the TTR90 offered a step-up in engine size and features while maintaining user-friendliness.
Manufacturing Location:
Primarily manufactured in Japan, with potential for assembly in other Yamaha global facilities.
Production Years:
Circa 2000-2007 (exact end date varies by region).
Awards:
Specific awards for the TTR90 are not widely documented, but the TTR series in general is recognized for its success in the youth and beginner off-road segment for its reliability and ease of use.
Consumer Ratings:
Generally receives positive consumer reviews for its suitability as a first off-road motorcycle.
Certifications:
Meets emissions standards for off-highway vehicles where applicable.
