Crafar's first competitive experience came in motocross in 1981 aboard a Suzuki TM75, competing in a local junior championship in New Zealand. He switched to road racing in 1985 and gradually built his career through national and regional series. He won Malaysia's Superbike championship in 1991, which raised his profile in the Asian motorcycle racing circuit. In 1993 he made his first foray into World Championship racing, taking a wildcard ride on a Harris chassis in the 500cc class before joining the Suzuki factory team in the 250cc class for the latter part of that season. He found the 250cc machinery ill-suited to his physique and did not continue in that class.
Crafar entered the Superbike World Championship in 1994 alongside fellow New Zealander Aaron Slight on a Rumi Honda RC45, finishing fifth overall. In 1995, when Doug Polen departed the factory Honda team, Crafar stepped up as the second factory rider alongside Slight, though the two operated under different liveries. The Honda became progressively more competitive through the season and Crafar recorded a second-place finish in race one at Assen. He spent 1996 and 1997 with the Kawasaki racing team. The 1996 campaign yielded a single podium and seventh overall. In 1997 he was more consistent, collecting two second places, five third places, one pole position, and a fastest lap to again finish fifth in the standings. Across four seasons in the Superbike World Championship he accumulated ten podiums — four second places and six third places — without reaching the top step of the rostrum.
Crafar returned to World Superbike in 2000 as a substitute rider for an injured Aaron Slight across two rounds. In 2002 he competed in the British Superbike Championship for Virgin Mobile Yamaha, finishing eighth overall with two third-place finishes, before retiring from professional motorcycle racing at the end of that season.
In 1998, Crafar moved full-time into the 500cc World Championship with WCM Yamaha riding a YZR500 on Dunlop tyres. The season produced his most celebrated moment: victory at the British Grand Prix at Donington Park. The win was the last for Dunlop in a dry-conditions premier-class race and the only non-Honda victory in a season otherwise dominated by the Japanese manufacturer. He added a second place and a third place to finish seventh in the championship, also recording the fastest lap at Donington Park and Phillip Island.
He remained with WCM for the early part of 1999, scoring points on five occasions, but the team's switch from Dunlop to Michelin tyres between seasons disrupted his performance. Unable to replicate his 1998 results, Crafar and WCM parted company mid-season. He also made a one-off appearance at Donington Park that year aboard an MuZ, finishing tenth. In total he started 25 premier-class and seven 250cc races, taking three podium finishes.
Following retirement from road racing, Crafar remained active in motorsport in several capacities. He competed in Extreme Enduro events, winning the Expert Class at the Red Bull Romaniacs competition in Romania in 2007. He also assisted the event organisers with course design and mapping for 2008 and 2009 before sustaining a serious back injury in a road accident while reconnoitring the 2009 route; surgery involving a metal plate and screws allowed a full recovery.
From 2006 onward, Crafar established himself as a rider coach, working with both track day riders and professional racers in one-to-one sessions across Europe. He became the series instructor and mentor for the European Junior Cup — a race series for 14- to 19-year-old riders held at World Superbike Championship rounds — for the 2011 and 2012 seasons. In 2011 he published Motovudu — Dark Art of Performance, a book and DVD instructional series filmed at Motorland Aragon, drawing on his racing and coaching experience.
In 2018, Crafar became pitlane reporter for Dorna, covering MotoGP, Moto2, and Moto3 on the world television feed. He subsequently added commentary duties for Moto2 and Moto3 qualifying sessions. From the 2025 season, he was appointed Chairman of the FIM MotoGP Stewards' Panel, succeeding Freddie Spencer in overseeing race officiating at the highest level of Grand Prix motorcycle racing.