Lot 4722: 1973 Honda CB 750

Based on my research from Honda CB750 forums, owner experiences, and technical resources, here are the most common engine problems with the 1973 Honda CB750:

Top 5 Common Engine Issues:

1. Cam Chain Tensioner Problems - The automatic cam chain tensioner can fail or stick, causing a distinctive rattling/knocking sound from the top end. This is probably the most well-known issue with the SOHC CB750 engines.

2. Valve Adjustment Issues - The valve clearances need regular adjustment (every 3,000-6,000 miles). If neglected, they can tighten up and cause burnt valves or loosen and cause excessive noise.

3. Oil Starvation - The dry sump system can develop oil delivery problems, especially to the camshaft and top end. Blocked oil passages or worn oil pump can cause serious engine damage.

4. Carburetor Balancing - The four Keihin carbs need to be perfectly synchronized. Poor carb balance causes rough running, poor idle, and reduced performance.

5. Starter Clutch Wear - The kick-start mechanism and starter clutch components can wear out, making starting difficult.

Other Notable Issues:

• Oil leaks from the dry sump system
• Points ignition wear (can be upgraded to electronic)
• Exhaust header cracks near the head
• Neutral switch oil seepage

The good news is that most of these issues are well-documented and have solutions. The CB750 community is huge, and parts are still readily available. Regular maintenance is key - these bikes reward owners who stay on top of valve adjustments and oil changes.