On the surface, building a custom and building a race bike are pretty similar endeavors. And there are quite a few builders with track records: in the US, there?s Roland Sands, Michael Woollaway of Deus, and Richard Pollock of Mule Motorcycles.
Their road going bikes differ in style, but all have one thing in common: the immaculate construction and detailing you?d expect to see on a track machine.

In Japan, the best-known equivalent is Shiro Nakajima of 46Works. When he?s not building vintage cafe racers for his clients, he?s out on the track.
Nakajima-san is a fan of vintage racing, and competes in a series called ?Legend Of Classic.? It?s held four times a year at the Tsukuba and Fuji Speedway circuits, and lately he?s been campaigning this stunning 1970 BMW R75/5.
Nakajima doesn?t just ride fast: he works fast too. Despite the amazing detailing, it took him just three weeks to build this BMW. And that includes the substantial mods and bracing for the frame.
As with any race bike, the story starts with the engine. The boxer twin was stripped down, blueprinted, and rebuilt with a tasty selection of hot rod parts?notably Carillo con rods and high compression pistons.

Capacity gets a boost from 745 to a whopping 979 cc, and there?s a hotter cam to improve breathing at high rpms.
Big valves (with titanium valve spring retainers) allow the fuel and air to get in and out faster, helped by a port and polish job and 39mm Keihin CR Special carbs.

Nakajima is also a ...