We're used to seeing desirable CX500s now, so I won't start this story with the usual Plastic Maggot pre-amble, but this build does take the whole pre-worn look to extremes with a corroded copper-coated tank that is the centrepiece of the bike and gives it the name CU29. The physicists amongst you will note that "CU" is copper on the periodic table and "29" is coppers atomic number (you knew that, right?). The bike was built by Luke at Robinsons Speedshop, and the brief was to keep it clean and simple, allowing the character of the bike to stand out, especially that agricultural Guzzi-esque engine and the lines of the open frame. "All the standard switches were binned and replaced, with the ignition, starter and lights all tucked out of sight under the seat, leaving just the horn and kill switch mounted up front. We opted for no clocks too just to keep the bare look up front" "The riding position was kept sweet by opting for a slight rise in the bars and keeping the foot rests as standard. The frame went through the standard de-tab and a loop was welded on with a slight rise, keeping the rest of the subframe standard." To allow the frame to stay open and uncluttered the battery is tucked away under the swing arm and the electrics are all secreted under the seat. RamAir filters feed air into the carbs while a simple black-wrapped 2 into 2 reverse-cone setup takes care of the exhaust gases and soundtrack. Chunky Firestone Deluxe tyres were fitted to give the bike an old-school feel, using the higher profile than standard, which gives the bike a lift and beefs-up the whole look. "The biggest challenge on this build was the tank. The original idea was to get it polished and copper-plated, then put matte lacquer over it, but the results just looked flat. The next attempt involved sand-blasting and then dipping the tank, without any finishing, and the result was perfect, with the added bonus of the extra colours this process bought out." As CX builds go, this one really lets the engine and frame stand out with clean uncluttered lines and simple black finish, and the copper tank adds a defining touch, complete with patina that gives the bike a steam-punk vibe. Straight bars and the stepped, diamond-stitched Brat seat also keep things mean and low. All in all, top Marks for another classy but unfussy Robinsons Speedshop build. See more of Luke’s bikes on The Robinson’s Speedshop Bike Shed Pages or Luke’s own Website and Facebook pages. Photos by Aaron Jones.