"What are the common problems with the 1973 Honda CB 750 engine?"

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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.

Lot 4722: 1973 Honda CB 750

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Lot 4722: 1973 Honda CB 750

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