The slump in sales of new motorcycles in August is "extremely disappoiinting", says Sue Robinson, director of the National Motorcycle Dealers Association (NMDA) which represents motorcycle retailers across the UK.

The latest new motorcycle and scooter figures show sales overall were down 3.4% against August 2012. Under 50cc scooter sales declined by 23.7%, whilst all larger over 51cc motorcycle sales increased by just 1.1%.

Robinson continued: “Sunny summer weather usually has a positive effect on motorcycle sales, however this was not the case in August. With September seeing the introduction of the new 63-plate it may be that buyers have chosen to delay their purchase to coincide with the plate change.

“Sales of heavy weight machines over 1000cc improved again during August up 21.8% compared to the same month last year. The Touring, adventure-sport and custom sectors led the upturn in sales with growth between 5.6% and 51.4%. Many of these large, high-spec bikes are purchased by established riders who, after seeing the improvements in the economy, may feel more confident in committing to buying such a big ticket item.

“KTM, Kawasaki, Harley-Davidson, Suzuki and Ducati also fell behind Lexmoto, a less established brand, last month. This hopefully indicates that customers of more traditional and expensive brands have held back their purchases until the introduction on the new September number plate.”