Yamaha CV80K/Riva 80 1983–1987 Scooter Factory Service Manual (P/N LIT-11616-03–63, 13T-28197-10)

• Yamaha OEM service publication set for the CV80 Riva platform: the CV80K Service Manual, P/N LIT-11616-03-63 / 13T-28197-10, 1st edition July 1982, plus the CV80N Supplementary Service Manual, P/N LIT-11616-04-11 / 32Y-28197-10, 1st edition March 1984
• 199-page PDF covering the base CV80K 13T configuration and the factory changes and service data issued for the CV80N 32Y configuration
• Model identification data includes CV80K frame and engine starting number 13T-000101 and CV80N engine starting number 32Y-000101; the CV80N supplement also lists Federal VIN *JYA32Y00FA000101**
• Factory repair coverage reaches the engine, V-belt drive and centrifugal clutch, transmission, Autolube system, carburetion and reed valve, drum brakes, wheels, front fork, steering head, starter, charging, lighting, signal, fuel-meter, and ignition-control systems

Content Overview

The base manual explains the CV80K's specialized systems before moving into maintenance and repair work. These include the electric fuel meter, variable-ratio V-belt drive, Yamaha "Vibeless" link engine mounting, energy-saving S.E. carburetor, B.V.S.-controlled automatic choke, and the START/RUN ignition control system. The V-belt section explains primary and secondary sheave operation and centrifugal weights, while the auto-choke material shows how the B.V.S. valve, fuel cock, and carburetor interact as cylinder-head temperature changes.

The CV80N supplement is not a stand-alone replacement manual. Yamaha states that complete CV80N service requires it to be used together with the CV80K Service Manual. It adds revised identification, maintenance data, electrical components and troubleshooting, specifications, cable routing, and CV80N circuit/wiring information. One configuration change is immediately visible in the carburetion data: CV80K uses a Mikuni VM13SS with a BP7HS spark plug, while CV80N lists a Mikuni VM16 and BP8HS plug. Clutch data also changes from a 3,500 ± 300 r/min stall specification on CV80K to 4,200 ± 300 r/min on CV80N.

Fitment note: the publications themselves identify CV80K/13T and CV80N/32Y; they do not state a blanket 1983-1987 model-year range. Match the model code, VIN/serial information, and installed configuration on the scooter rather than relying on model year alone.

Factory Procedures & Diagnostic Depth

Repair procedures include engine removal and installation, cylinder-head/cylinder/piston and ring inspection, CDI magneto service, primary and secondary sheave/clutch disassembly and inspection, starter clutch and starter motor work, transmission service, crankcase splitting and crankshaft installation, and Autolube pump inspection, adjustment, and bleeding. Carburetion coverage includes carburetor removal, disassembly, checking, assembly, and installation, plus reed-valve inspection.

Chassis procedures cover front and rear wheel/brake work, meter gear service, front fork repair, steering-head service, and main-stand removal and installation. Electrical diagnosis is organized around circuit diagrams and fault-finding checks for the ignition, starter, charging, lighting, and signal systems. The CV80N supplement adds troubleshooting for the ignition control unit, sidestand switch, and sidestand control unit.

Representative views include the CV80K Circuit Diagram, CV80N Circuit Diagram/Wiring Diagram, Primary Sheave–Secondary Sheave–Clutch exploded view, Crankcase–Crankshaft view, Front Wheel–Front Brake view, and Front Fork exploded view. Cable-routing pages also show harness, brake-cable, throttle-cable, CDI-lead, fuel/vacuum-pipe, and breather routing.

The special-tool section identifies Yamaha tooling by part number, including the YU-01135 crankcase separator, YM-01189 flywheel puller, YU-90050 crankshaft installation set with YU-90063 crank adapter, YS-28891 / YM-04045A clutch removing tools, YU-01268 steering nut wrench, YU-03112 pocket tester, and YU-33261 coil tester.

Specification Previews

Shop data includes a 15 Nm (11 ft-lb) cylinder-head tightening torque and transmission oil capacity of 180 cc for a periodic change / 200 cc total after overhaul. For ignition diagnosis, the CV80K test data specifies 34.6 Ω ±10% for the pickup coil, while the CV80N component table lists 34 Ω ±10%. Both identify a 378 Ω ±10% CDI source coil; the separate flywheel-magneto charging coil is specified at 0.6 Ω ±20%.

There is a manual-internal torque discrepancy worth noticing before repair: the transmission-oil replacement procedure specifies 20 Nm for the drain bolt, while the appendix tightening table lists 18 Nm for the M8 x 1.25 drain bolt. This is a value that should be cross-checked in context rather than transferred from one section without verification.

The manual also flags several assembly traps. The secondary-sheave/clutch section warns that installing the clutch-housing oil seal upside down can cause leakage and that oil or grease must be kept off the V-belt, sheave surfaces, clutch housing, and clutch linings. During transmission assembly, the drive-axle serrations can roll the oil-seal lip if the axle is installed carelessly. In the charging system, Yamaha warns that the silicon rectifier can be damaged by overcharging, short circuits, or incorrect battery-lead polarity.

Yamaha wrote this publication for dealer and qualified-mechanic use and assumes basic repair knowledge. Its safety notes specifically address battery gas and acid hazards as well as ventilation during engine-running tests.