Cosmo Sport (110S)

1967-1972 / Coupe / Japan

All Cosmo Sport (110S) problems All workshop issues

Critical Electrical System

Wiring Harness Degradation

Symptoms

Intermittent electrical faults, blown fuses, non-functioning lights or gauges, and in the worst case, electrical fires.

Cause

The original wiring harness uses rubber-insulated copper wire. After 50+ years, the insulation becomes brittle, cracks, and falls off, exposing bare copper. Short circuits follow. Previous owners may have spliced in repairs using inappropriate wire, connectors, or techniques.

Fix

A full wiring harness assessment is essential.

Minor faults can be repaired in situ.

If the harness is severely degraded, a complete rewire using a custom harness is the only reliable solution.

Cost: $2,000-5,000 for a custom harness and installation.

Cost mentioned in fix

Cost: $2,000-5,000 for a

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// More Cosmo Sport (110S) problems

Other known issues

Minor Engine, 10A Twin-Rotor (982cc)

Apex Seal Wear

Loss of compression, reduced power, difficulty starting (especially when cold), blue-white exhaust smoke, and eventually misfiring and inability to idle. A rotary engine with worn apex seals is an engine that needs a rebuild, there is no halfway measure.

Common Engine, 10A Twin-Rotor (982cc)

Hard Cold Starting

The engine cranks extensively before firing when cold. May require multiple attempts. Once warm, starting is normal.

Minor Engine, 10A Twin-Rotor (982cc)

Oil Metering Pump Failure

Without lubrication, the apex seals run metal-on-metal against the rotor housing. Wear accelerates catastrophically. The engine may seize.

Critical Engine, 10A Twin-Rotor (982cc)

Cooling System Inadequacy

Engine overheating, particularly in traffic or on hot days. The temperature gauge climbs steadily, coolant may boil over, and in extreme cases the engine suffers heat-related damage (warped housings, blown coolant seals).

Common Ignition System

Points and Condenser Degradation

Misfiring, rough running, difficulty starting, inconsistent idle.

Minor Ignition System

Spark Plug Fouling

Misfiring, rough idle, loss of power. Plugs come out with heavy carbon or oil deposits.

View all 10 Cosmo Sport (110S) problems