Honda CB400F

Enter the CB400F

The Honda CB400F was a gem of a little bike built in the 1970's by Honda to replace the old Honda 350 which had often been seen as underpowered. The engine was actually a 408cc that revved to a heady 10,000rpm. All Honda did was take the 350 engine and took the bore out to 51mm to give the capacity increase. Power went up to 37 bhp at 8,500 rpm compared to the 32 at 9,500 rpm of the 350 four. The Honda CB400F also got a six-speed gearbox as opposed to the five-speed the 350 had.

Many people were both surprised and disappointed when the Honda CB400F was dropped after only a few years to fetch out the much more lack lustre range of twins that never caught the public's imagination in the way the little four had.

The bike was known by a few designations through its life, such as the CB400/4, the CB400 Super Sport, the CB400F, the CB400Four, the list seemed endless.

I actually owned a 1976 Honda CB400F in the early eighties for a while and it was a pleasant bike to ride in many ways. Its main problem for me was the fact that at a steady 70mph cruise it was spinning at 7,000rpm which got a bit tedious to listen to after a while. And that was even with one of the first six-speed gearboxes, a bit of a novelty at the time.

Honda CB400/4

The performance was adequate for a bike of this size. The Honda CB400F was good for just over the ton, about 102-103mph and handling was excellent. The single front disc had to work quite hard but never felt poor to the point of being dangerous.

Reliability was generally good. It suffered from the usual Honda malady of the time: short lived cam chain life. Beyond that I never had any problems with mine, easy to service, easy to ride, it was easy to see why it was such a popular bike with so many people. Its compact size made it a hit with female riders as well, weighing in at around 400lbs (the bike not the female riders).

The Honda CB400F was the mini-superbike of its day.

The Honda CB400F's Exhaust System Design

The Honda CB400F's distinctive exhaust system. Pic courtesy AGalaxy, Wikimedia Commons, CC-A-SA-3.0
The Honda CB400F's distinctive exhaust system. Pic courtesy AGalaxy, Wikimedia Commons, CC-A-SA-3.0

Technical Specs for the Honda CB400F

The Honda CB400F was dwarfed in technical comparison to its might brother the Honda CBX1000 but the engine was a 408cc air-cooled in-line four-cylinder with four carburettors and a sohc.

Bore and Stroke were: 51mm x 50mm for a capacity of 408.6cc.

Compression ratio was 9.4:1.

Ignition was twin coils and twin contact breakers.

I have seen power outputs between 37bhp at 8,500rpm and 40bhp at 9,000rpm quoted, so take them as a ball park figure, and a dry weight of 392lbs (178kg).

It had a six-speed transmission with chain final drive and a steel-tube cradle frame.

A single front disc and drum rear brakes.

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