The KTM RC4 is seen here disguised in Cagiva Mito bodywork

KTM insiders have revealed the first details of the RC4 single-cylinder sportsbike which the firm has been developing in secret.

You can read all about the bike in MCN next week, but the headline numbers include a power figure of 78bhp, which is allied to a low weight of just 132kg – giving the a power-to-weight ratio similar to a supersports 600 bike.

Tests have shown that early prototypes can top 140mph.

This picture shows the very first test machine KTM developed, using the chassis from the new Duke 690 wrapped in Cagiva Mito bodywork. But the final machine will be very different, with its own unique frame design, a retuned version of the 654cc single-cylinder engine and angular styling to link it to the RC8 Superbike.