Big Bore 400/4: Honda “CB466F” Café Racer

Honda CB400F Cafe Racer

466cc Honda Cafe Racer from Motorelic… 

First available in 1975, the Honda CB400F (“400 Four”) showcased Honda’s technical prowess. Here was a miniaturized 408cc version of their larger fours, complete with café-inspired styling, nimble handling, and an exhaust note reminiscent of Honda’s small displacement race bikes.

Honda CB400F Cafe Racer

Robert Smith of Motorcycle Classics still remembers his first ride on a friend’s 400 Four in 1975, back when his daily driver was a BSA Victor, a “partially civilized dirt bike.”

“A friend offers me a ride on his new CB400F. I’m not going to like this, I tell myself. It’s a wussy rice burner. I’m still trying to kid myself that it’s nothing special when I hand it back. Just six years separate the Beezer from the F-bike, but the contrast is huge; it’s like the Space Shuttle just landed in the Stone Age.”

Then there was the exhaust note coming from the 4-into-1 pipes — possibly the loveliest set of factory pipes ever on a production bike.

“We’re all familiar now with the howl of a high-revving multi exhaling through a single pipe, but in 1975 this siren sound was new on the street.” –Motorcycle Classics

Honda CB400F Cafe Racer

If there was one weakness to the 400 Four, it was the power output. It was never a bike that was about straight-line acceleration, but in 1975, with muscle cars and two-strokes still prowling the streets, 37 hp and a 1/4-mile time in the low 14s just didn’t cut the mustard. The CB400F never sold well, especially in the States, and has developed something of a cult following over the years. It makes you wonder: What if the 400 Four had just a bit more punch?

Honda CB400F Cafe Racer

Enter one of our favorite builders, Sean Skinner of Virginia’s Motorelic, who got a call from a customer in Baltimore with a ’75 CB400F that had a 466cc big bore kit, hotter cam, and some light porting done back in the 80s. Sean’s interest was immediately piqued, as was ours when he told us. After all, we’ve featured some 12-15 custom 400 Fours over the years, and none of them had these mods.

Honda CB400F Cafe Racer

The owner, Roger, wanted to transform the bike’s style and performance to match engine, creating his dream bike. When Sean saw the donor, he could tell it was in solid shape — but that wasn’t going to stop him.

“I could almost hear the tears of the purist hitting the ground as I thought about how I was going to cut it up. But, that’s what I do.”

Honda CB400F Cafe Racer

Sean gives us the full rundown on the build below, but highlights include a GSX-R front end, rear monoshock conversion, custom 18-inch wheels laced up by Virginia’s own Cognito Moto, Motogadget electronics, Suzuki GS450 tank, front fairing and mounts, and a custom subframe.

The tail section was built from an NS50 tank and topped with a Counterbalance Cycles saddle. The engine breathes through CR26 carbs and a custom 4:4 exhaust with Cone mufflers, and Sean vapor-honed the cylinder, head, and valve cover before giving the motor a coat of VHT high-temp “Cast Iron.”

Honda CB400F Cafe Racer

Sean says he couldn’t wait to hop on the finished and feel the difference.

“What an incredible bike to ride. From the modern suspension and brakes to the power delivery of that not so little 466cc engine. Hearing those pipes and those carbs on hard acceleration was music to my ears. I wish I could keep it.”

Below, Sean gives us the full in-depth story of the build, with more photos courtesy of Jonathan Thorpe.

CB400 Four Café Racer: In the Builder’s Words…

Honda CB400F Cafe Racer

This bike was brought to me from Baltimore, MD, and is owned by Roger B. Roger called me up and told me about this bike that he has had since the 80s. A 1975 Honda CB400F. Back then he had a 466cc big bore kit installed, a road track cam and some light porting done. This piqued my interest.

After a long conversion about what he wanted his dream bike to become, Roger called the tow company and had the bike brought to me. Once I saw the bike I knew it had great bones and was in pretty decent shape. I could almost hear the tears of the purist hitting the ground as I thought about how I was going to cut it up. But, that’s what I do.

Honda CB400F Cafe Racer

The first order of business was to get on the phone and order up some custom 18in wheels from Cognito Moto, find a GSXR front end and a CB550 swingarm. Roger requested a mono shock design that would stiffen the swingarm and Cognito happened to make a 550 rear disc brake conversion hub!

Honda CB400F Cafe Racer

All I had to do was make everything fit. The swingarm didn’t just fit. It required some minor modification to the pivot and bushings. I used 1″ DOM tubing to shape the design of the monoshock set up and used an Ikon “dial-a ride” shock. I noticed right away that I would need an offset front sprocket to clear the new 140 rear tire. I lucked out and found the perfect front sprocket at PBI Sprockets.

Honda CB400F Cafe Racer

Once the suspension was sorted and the bike had the stance and geometry that I liked, I was able to see how the subframe needed to be changed. I started by cutting the entire back off the frame leaving just enough of the original to sleeve and start my design. A simple standard design was made with a slight kick up to properly clear the tire.

The rear tail piece was made from the back half of a Honda NS50 tank. It had a very similar shape to the GS450 tank I chose to use for the build so it flows nicely. The tail section holds the big 12 cell AntiGravity battery and start solenoid. Keeping the bike looking as tidy as possible. Luckily the gas tank didn’t need too much to make it fit.

Honda CB400F Cafe Racer

Once the tank and tail were mounted, the seat was next. I made the steel pan hug the tank and tail. Then shaped the foam to the desired look and thickness and sent it off to Counterbalance Cycles for a smooth black leather upholstery.

Honda CB400F Cafe Racer

Now on to what I considered more difficult, the fairing mount and fairing. I ordered the Thruxton fairing from Airtech Streamlining. I was hoping it was wide enough to clear the massive GSXR forks and flow with the tank. I was not disappointed. It was going to work perfectly.

Honda CB400F Cafe Racer

Working by yourself has its drawbacks when something needs to be held while something else is designed or measured. I had to get creative balancing the fairing and making the mount. Tape, blocks of wood and some sticky foam were my shop helpers to temporarily hold the fairing while I pieced the mount together.

Honda CB400F Cafe Racer

The mount was quite the challenge to design and build but in the end it turned out better than I hoped. It also held the beautiful Motogadget gauge.

Honda CB400F Cafe Racer

Speaking of Motogadget, Roger went all out and requested an M-unit, 3 button switches, grips and turn signals to match the gauge. They are top notch jewelry for any beautiful motorcycle. The front fender and mirrors were from Messner Moto and they are very slick parts.

 

The bike is looking quite good now. The last thing Roger had to have was a custom set of 4 into 4 exhaust. I called up Rich at Cone Engineering and ordered four 13in big mouth mufflers and all the bends I thought I would need.

Honda CB400F Cafe Racer

I love building exhaust. Mostly just to hear it when I’m done. I tried to incorporate the iconic bends of the stock 400 pipe but still keep the flow of each pipe looking correct. The end result is a cross between the CB750 and the 400 with an amazing raspy sound.

Honda CB400F Cafe Racer

At this stage the bike is looking like it’s ready to ride, so it was time to tear it all down to make it pretty. I handed all the powder coating off to Right-A-Way Powder and they laid down a sexy gloss black. The paint color Roger picked was the Monarch Orange metallic from Nissan.

Honda CB400F Cafe Racer

While that was being handled I got to work on making the engine look as good as everything else. I also wanted to inspect everything that was done nearly 40 years ago during that big bore install. Once apart I saw that everything looked new. The engine clearly didn’t run for very long — life got in the way, I guess.

Honda CB400F Cafe Racer

I vapor-honed the cylinder, the head and valve cover, gave the cylinder and black coat of paint, and reassembled with new gaskets and seals. The block got a few coats of “cast iron” from VHT. It’s a favorite of mine. I finished off the engine build with a new clutch kit and all stainless hardware. The engine is fed with gorgeous CR26 carbs.

Honda CB400F Cafe Racer

Assembly went quickly. Everything fit back together just how I took it apart. The M-unit made the wiring simple and tidy. Once it was together I couldn’t hardly wait to ride it and feel the difference all the hard work and investment made.

Honda CB400F Cafe Racer

What an incredible bike to ride. From the modern suspension and brakes to the power delivery of that not so little 466cc engine. Hearing those pipes and those carbs on hard acceleration was music to my ears. I wish I could keep it.

Follow the Builder

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3 Comments

  1. Roman JURIŠ

    One of the most beautiful Café Racer bikes ever

  2. Brian Fawcett

    So, maybe I missed it somewhere, but where is the soundtrack of this wonderful machine?
    after reading all the Blah Blah Blah! i think we deserve to hear the melodies of this wonderful machine?

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