In addition to the Yamaha engine lease, Honda is building a 'Production' version of its RC213V prototype, while Ducati recently revealed it could offer this year's GP13 motorcycle
for use with next year's full standard ECU, creating a further privateer option.
Official factory prototypes will also be forced to use the standard ECU hardware from 2014, but can continue developing their own software, for which they face a penalty of four litres less fuel per race and five - rather than twelve - engine changes per season.
CRTs also have a softer rear tyre available relative to the factory machines.
The class-leading Aprilia ART, based on the RSV4 Superbike, is the only complete CRT motorcycle currently on offer from a manufacturer. The other machines have been created by combining a bespoke racing chassis (FTR, Suter or PBM) with a modified Superbike engine (Honda, Kawasaki or BMW).
Although Aprilia's involvement in CRT caused initial controversy, the ART 'format' of an off-the-shelf production MotoGP bike looks to have provided a template for Honda's Production Racer.
Unlike the Yamaha engine lease, the privateer Honda will not feature pneumatic valves, or the RC213V's prized seamless-shift gearbox, allowing the Honda to be sold rather than leased.
Top CRT rider Aleix Espargaro (Aspar ART) has finished eighth at the last three events. The Spaniard beat all four Ducatis and one Yamaha at last Saturday's Assen round.