From pit bikes to a full-size 500cc two-stroke.
From a trade-fair pit bike to a global brand
Thumpstar was founded in Australia in 2004 by Timothy Hunter, a motorcycle dealer and racer. At a trade fair in late 2003 he came across a pit bike, decided he could improve it, and in April 2004 signed a contract with a Taiwanese company to help build his own. Thumpstar's first models, released between 2004 and 2006, were the JNR 90cc, the Super Hunge 110cc and the Pro Hunge 125cc. The Pro Hunge, with its CNC-machined, TÜV-certified billet T6 heat-treated alloy frame, was a hit, and Wikipedia reports global sales of more than A$45 million in the brand's first 13 months.
Setbacks and a restart
The early boom brought problems too. Thumpstar's own history describes trademark infringement and heavy infrastructure costs, and in 2007 Hunter rebranded as Terra Moto, which did not sell well. In 2011 he was approached about reviving Thumpstar. An agreement was signed on 10 May 2012 to restart the company with three models: the TSX 88cc, TSX 125cc and TSR 160cc. By early 2015 the range had grown to more than 16 models from 50cc to 250cc across five families: TSB (basic), TSX (mid-range), TSR (racing), TSK (kids) and -C (competition). Since 2013 Thumpstar has developed junior motocross bikes, and in 2015 it released competition versions for motocross racing. Its riders have appeared at the World Mini Moto Championships in Las Vegas, with team names including Mike Brown, Dan Cartwright and Mike Leavitt.
Growing up: two-strokes with Spanish know-how
In 2017 Thumpstar approached Josep Pibernat, a co-founder of GasGas and founder of the trials brand Jotagas, about building two-strokes. Pibernat had kept the tooling and technology from a cancelled Jotagas enduro project, and the collaboration produced carburetted 250cc and 300cc two-stroke models, revealed in October 2019. Thumpstar's stated long-term plans then included racing the 250 in US Arenacross and building high-performance 250 and 450 four-strokes.
The 500: a five-year gamble
The big step came at AIMExpo in Las Vegas in February 2025, where Thumpstar unveiled a full-size 500cc two-stroke. According to ADVrider, the project started about five years earlier and included two years of testing. Staff said they had heard many requests for a big two-stroke on social media. The engine comes from BRC Racing of Calgary, Canada, which specialises in Honda CR500-based engines. Wikipedia describes it as an original BRC design, with BRC making some components and Thumpstar making the rest. The engine is carburetted and counterbalanced, with a six-speed gearbox and both electric and kick start.
The prototype on the stand
The show bike had a CNC-machined swingarm, Excel rims and Öhlins suspension. Thumpstar stressed it was a one-off, built by its Australian and American staff and finished just days before the show. Thumpstar USA's Jason Young told Dirt Bike magazine: "There hasn't been a 500cc two-stroke dirt bike in production in more than 20 years. We're excited to see how people respond." He said a production version would differ from the prototype. ADVrider reported that production bikes would probably use more basic suspension to keep the price under US$10,000.
Market and competition
No major manufacturer has offered a 500cc two-stroke motocross bike since Honda's CR500 ended production in the early 2000s. Riders who want one today usually rebuild old CR500s or buy specialist engines like BRC's. A production Thumpstar 500 would face almost no direct competition. Thumpstar admits the business case is unproven: in its words, nobody knows yet whether people will buy one.
Why Most Improved
Gold Seal Most Improved recognises the biggest step forward by a maker. Thumpstar has gone from 90cc pit bikes in 2004, through a collapse and restart, to Spanish-developed two-strokes and now a full-size 500cc prototype. It is the clearest example of a brand growing up this year. The award recognises that progress. It is not a verdict on a production bike, because one does not exist yet.
What to watch next
The key questions are what a production version will look like: which suspension it gets, how close it stays to the BRC-built prototype engine, and whether the target of under US$10,000 survives. Thumpstar says a production bike will differ from the show bike, so we will review the award story when one reaches dealers.
The bigger picture
Small brands rarely jump from pit bikes to an open-class two-stroke. Most new brands grow one size class at a time. Thumpstar chose the hardest and most niche step on purpose, building on a decade of junior motocross bikes and its 250 and 300 two-strokes.
Specification breakdown
- Engine: BRC Racing 500cc two-stroke single (Honda CR500-based).
- Features: Counterbalancer, 6-speed gearbox, electric + kick start.
- Fuel system: Carburettor.
- Chassis (show bike): CNC swingarm, Excel rims, Öhlins suspension.
- Status: One-off prototype shown at AIMExpo, February 2025.
- Price: Target under US$10,000 (production intent, per ADVrider).
Why it won
Best known for its pit bikes, Thumpstar unveiled a full-size 500cc two-stroke at AIMExpo 2025 in Las Vegas. It is the clearest step up any maker in the field has made. Thumpstar says it aims to return a 500cc two-stroke dirt bike to production after more than 20 years.
Watch
Video: Thumpstar BRC 500 2 Stroke | Unveiled at 2025 AimExpo – Thumpstar