Superleggera Slider: GM Motorcycles’ Aluminum-Clad Kawasaki KX250

# Project overview Giovanni "Gio" Mariani of GM Motorcycles transformed a 1999 Kawasaki KX250 that had sat in storage for eight years into a flat-track slider with an aluminum-clad, superleggera-style body. The build started as a bid to get into the Wheels and Waves festival, which enforces strict visual and category rules. What began as a plan for simple flat-track graphics became a full custom when the bike was judged too modern for the festival's vintage aesthetic.

# Why the build changed course

# Fabrication strategy and logistics Australia. To bridge that gap he found a matching 1999 frame, tank and radiators locally to use as a jig. He fabricated a custom rear subframe and a tubular support structure to carry the new body. Paper templates were digitized into vectors, laser-cut, and then shaped with a power hammer and English wheel.

# The body: materials, methods, finish

# Mechanical changes for flat-track use To turn a motocrosser into a slider, the stock Showa suspension was internally revalved and shortened significantly — 100 mm dropped up front and 20 mm at the rear. Wheels and tires were changed: cracked factory rims were replaced with 19-inch Excel rims laced to the stock hubs and shod with Anlas flat-track rubber. The engine breathes through a full FMF Gold Series exhaust, and Ventura flat-track bars complete the cockpit.

# Collaboration and shop work Metal-shaping specialist Cristian Sosa joined the project for a masterclass and helped convert templates to digital forms. Mariani worked out of Purpose Built Moto on the Gold Coast with fabricator Cody Jermyn, relying on both traditional hand tools and shop equipment. Late-night sessions and cross-continental planning were key to finishing the job on time for the festival.

# Final assembly and outcome Mariani packed the finished bodywork in his checked luggage and traveled back to Italy to bolt it onto the resurrected KX chassis. The completed machine met the festival's custom category requirements and secured Mariani entry to Wheels and Waves.

# What stands out This build combines practical problem-solving with old-school metalwork. The one-piece aluminum skin is built for track durability rather than weight obsession, and the project required overcoming a 10,000-mile logistics problem by sourcing local donor parts and coordinating fabrication across workshops and continents.