KTM

KTM LC8c engine nearly ready
by Ben Purvis

KTM's parallel twin LC8c engine has proved to be an extraordinarily adaptable engine since it debuted in the 790 Duke in 2018 - appearing in two capacities and powering adventure bikes, roadsters and even the track-only RC-8C race-rep - but it's about to be superseded by a completely new design that will be the basis of KTM's next generation of Duke and Adventure middleweights as well as the highly anticipated RC990 sports bike.

These are the first pictures of the new engine, which have emerged via design registrations from KTM's joint venture with CFMoto, manufacturer of KTM's current parallel twin engines. They reveal a design that carries over key design elements of the original LC8c - initials that stand for 'Liquid-Cooled, 8-valve, compact' - but is almost entirely new when it comes to the major castings and components.

The evolution is believed to be down to the engine's growth to nearly 1000 cc in its next-generation form. The original LC8c was launched as a 799 cc engine, the '790', and grew to 889 cc in '890' form thanks to a bigger bore, increasing from 88 mm to 90.7 mm while retaining the original 68.8 mm stroke. To grow again - rumours say the next version will be called '990' and have a capacity of around that mark - the LC8c needs a longer stroke, hence the redesign. 

These images show that the cylinders of the new LC8c are taller than the current design, indicating the longer stroke, while the cylinder head has been redesigned to be more compact, allowing the overall size to be essentially unchanged. The engine mounts are in the same positions as before, allowing the new engine to be bolted to existing frames if required, but all the castings for the engine block, cylinders and head are new.

Other changes include a completely redesigned oil sump, with its main capacity moved to one side to make space for an under-engine exhaust system and catalytic converter, while the rear part of the transmission case has been cut back to make more space for suspension components.

The new engine has been spied undergoing tests in prototypes for the next-generation '990' Duke and the RS990 sports bike, which will be KTM's first fully-faired, high-performance street bike since the original RC8 superbike was discontinued. The naked 990 Duke street bike is expected to be the first to reach production, probably as a 2024 model. When it arrives, it's likely to replace the current 890 Duke, although the older LC8c engine will remain in production for the more affordable 790 Duke and the Adventure models that currently use it, as well as the CFMoto 800MT and 800NK. Over the following years, the 990 Adventure and RC990 are expected to arrive as the updated LC8c becomes KTM's main engine for its middleweight line-up.