What Killed the Kickstart? | CB550 Review

Quick Overview

The Honda CB550's kickstart mechanism was eliminated in favor of an electric starter because modern motorcycles are expected to be reliable and efficient, while older designs like the CB550 required manual kicking, which was less reliable, especially with weak batteries, and the engine's firing order meant kickstarting could result in dangerous kickback if the rider failed to properly disengage the kickstart shaft.

Key Points: The Honda CB550 is praised as Honda's most famous middleweight bike from the 1970s, setting a standard for its class. Unlike modern bikes, the CB550 uses a kickstart, which the presenter demonstrates is necessary when the battery voltage drops (e.g., to 10.38V or 11.47V shown on a multimeter). The four-cylinder engine features 8 valves and four carburetors, and its displacement is 550cc. The kickstart mechanism engages the transmission, which rotates the crankshaft, but the kickstart shaft must disengage during normal operation or when the engine fires to prevent kickback. Kickback occurs when the engine fires while the piston is moving up, forcing the kickstart lever backward, which can be dangerous if not properly managed by the rider. The CB550's top speed is cited as 160 km/h, and its smooth, fast-revving engine was superior to many peers of its time. The video contrasts the kickstart method with modern race bikes and everyday riders who rely solely on electric starters, highlighting the necessity of manual starting on vintage machines with weak batteries.

Context: The video focuses on the 1970s Honda CB550 motorcycle, analyzing its features, particularly its manual kickstart mechanism, contrasting it with modern electric-start bikes. The presenter explains the mechanical function of the kickstart, the inherent risks like kickback, and why this feature became obsolete due to advances in charging systems and the demand for seamless reliability in contemporary motorcycles.

Detailed Analysis

The video reviews the classic Honda CB550, noting it was a benchmark middleweight bike in the 1970s, known for its smooth, fast-revving 550cc, four-cylinder, eight-valve engine capable of 160 km/h. The core discussion revolves around its kickstart mechanism, which is necessary when the electrical system, specifically the battery (shown reading low voltages like 10.38V or 11.47V on a multimeter), cannot power the electric starter. The presenter demonstrates the physical act of kickstarting, explaining that engaging the lever rotates the transmission, which turns the crankshaft. A critical point is that the kickstart mechanism must disengage from the transmission once the engine starts; otherwise, a backfire or explosion on the compression stroke causes dangerous kickback, forcing the lever violently in reverse, a hazard absent on modern electric-start bikes. The presenter shows the kickstart lever engaging the gearbox internally via a ratcheting gear system, emphasizing that this complex, manual step is what modern motorcycles avoid entirely. The video concludes by contrasting the raw, sometimes difficult starting procedure of the CB550 with the seamless nature of modern bikes, which use powerful alternators and starters.