What is the normal cylinder pressure for CB400?
2 Answers
CB400 cylinder pressure is considered normal if it is not lower than 700KPa. Below is the relevant introduction of Honda CB400: 1. Power: Equipped with a 399cc parallel twin-cylinder water-cooled engine, with a maximum output power of 33kW (44.9 horsepower)/9000rpm, and a maximum torque of 37Nm/7500rpm. The engine is paired with a 6-speed MT transmission, and the maximum speed can reach 157km/h. 2. Tires: The specifications are front 120/70-17, rear 160/60-17, with a wheelbase of 1416mm.
I've been riding my CB400 for several years. The normal cylinder compression should be between 10 to 12 kg, depending on the year and condition of the bike. It's more accurate to measure when the engine is warm, and the compression difference between the four cylinders should ideally not exceed 1 kg. If there's noticeable shaking when the engine is cold or difficulty starting, it's likely due to low cylinder compression, and you should check the valve seals or piston rings. During my last maintenance check, I measured the compression and found one cylinder was only at 9 kg. Upon disassembly, I discovered the valve stem was deformed. I recommend fellow riders to regularly check their cylinder compression, especially before long trips, as it directly reflects the engine's condition. Don't wait until blue smoke appears to fix it—by then, the damage could be significant.
