Home / Custom Motorcycles / Honda CL450 Brat by Tom Hernden

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In 1974, at just 19 years old, Tom Hernden won the Florida State Modified Championship at Twin City Dragway in Oldsmar, Florida, racing the 1973 Honda CL450K5 drag bike he built.

Fast forward 40 years, and Tom decided it was time for a street-legal “reboot” of that championship-winning bike — a plan he’d been harboring for decades. The result is the CL450 brat bike you see here, running the same camshafts and very similar 11.6:1 big-bore pistons as his original drag bike.

We love a bike with such a special story behind it. Below, we get all the details from the builder himself.

Honda CL450 Custom:  In the Builder’s Words

(Words by Tom Hernden. Highlights by us.)

When I was 19, I built a 500cc modified-class drag bike from a ’73 Honda CL450K5. I raced it regularly and quite successfully at local central Florida dragstrips, winning the Florida State Modified Championship in November 1974 at Twin City Dragway in Oldsmar FL.

Late last year I found another CL450K5 and put in motion something that had been in the back of my mind for over 40 years since letting my drag bike go — a street-legal reboot of that combination.

After lots of hours of research, I located the same camshaft supplier for the DOHC engine and ordered a set. My previous piston supplier, Powroll, was out of business so I had to source the big-bore pistons I wanted elsewhere. I found Team Hansen of Honda 450 road racing fame and bought their 74mm, 11.6:1 gas-ported racing pistons to make it 497cc, and picked up another set of 36mm Mikuni carbs to round out the engine needs.

I wanted to keep the bike period correct in many ways with OEM gray cables, right handlebar switch, grips, and other little touches while doing a few mods of my own preference and design. I kept the stock chrome front fender but chose a 5″ aftermarket rear fender to help make the bike look a bit slimmer and got it chromed. To further make the bike look slimmer and smaller, I bought a chrome version of a Honda monkey bike tank holding only 1.8 gallons and paired that with a lightweight plastic-based brat seat.

With the welding and fabrication experience of an old friend, we modified the tank mounts, added proper seat mounts and modified the rear of the frame for the new fender. Going completely different, I chose a rectangular LED off-road light with end mounts for a headlight mounted on polished aluminum ears. I replaced the huge factory tail light with a smaller 1970 Honda SL175 light assembly with LED bulb. Changed the handlebars to a favorite of mine for street riding, the CB400F bars with only 1.75″ rise.

Removed the electric start and used a machined plug with o-ring to close the opening in the crankcase and with all high-load electrics now gone, bought a 4 amp lithium ion battery that is one-third the size of original and only weighs 1 lb. I used flat steel to fashion a new battery box and mounted it between the bigger Mikuni carbs under the revised seat bracing on the frame.

During a second fabrication session, we modified the stock brake pedal to shorten it and re-mounted it with the right rear footpeg, shaping a new brake rod around the swingarm to complete the setup. I used a Suzuki shift lever with a section of linkage rod connected to a Honda CB350 shift arm on the shift shaft for the rear-set arrangement. We also moved the stock ignition switch bracket up to a new location above where it was originally located, now nestled in the frame right in front of the smaller tank.

I lowered the stock front forks 1″ after replacing the seals, and bought 1.5″ shorter shocks for the rear to give the bike a low stance equivalent to my previous drag bike. Since drag pipes were no longer available for the 450, my friend and I hand-built pipes from a set of mandrel bends for a Yamaha XS650 and I had them ceramic coated.

After the frame mods were done, the frame and swingarm went out to get powdercoated red — something Honda had done in the ’60s on a limited number of CL77s (305 Scramblers) — to make it stand out. I sanded and polished the cam end caps, points cover, oil filter and alternator covers, front valve cover, both brake backing plates and front fork lower legs on a buffing wheel for a chrome-like finish. All other frame parts were stripped and painted satin black, along with the refurbished tach and speedometer, and all wiring was trimmed and routed under the gas tank for a clean look in the front.

I painted the outer engine covers with Honda Marine Oyster Silver, a rich-hued silver that complemented the other natural aluminum engine parts nicely. All new JIS screws were used in the engine to retain the OEM look, and nuts and bolts were replaced with OEM-styled appearance anywhere the factory parts were corroded.

Watch the Assembly!

Tom put together this sweet GIF of the initial assembly — pretty cool!



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  1. ….looks bigger than, i suspect, it really is……….

  2. Henri du Plessis

    It is sweet, I dig it.

  3. What a beautiful motorcycle – well done! One of the best!

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