[cycleworld.com] - KTM’s Larger, More Powerful, Next-Gen LC8c Twin

[Ninjette Newsbot]

More details emerge about KTM’s brand-new LC8c engine that will likely power a variety of models and produce as much as 140 hp.

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KTM’s new LC8c engine (left) and the existing version (right). (KTM/CFMoto/)Back in January we revealed the first detailed images of KTM’s next-generation parallel-twin engine, and now a new patent application has given a glimpse inside the new LC8c—revealing details pointing at improved performance and reliability.


The new LC8c is new from the oil pan up. (KTM/)The new twin looks similar to the current 889cc “890? version of the LC8c but is actually almost entirely redesigned. Every casting from the oil pan to the cam cover is new, with different cases, cylinder, and cylinder head. The only carryovers are bolt-on parts like the throttle bodies and water pump. There’s plenty of rational speculation that the engine’s capacity will increase to nearly 1,000cc, earning the new twin the “990? designation that is a logical progression from the 790 and 890 versions that came before it. The new patent appears to back that theory up.

When KTM filed design registrations for the physical appearance of the engine, it appeared that the deck height, where the cylinder head meets the cylinders, was taller than its predecessor. The new technical patent for the engine seems to confirm that, showing a detailed cutaway drawing of the next-gen LC8c (Liquid-Cooled, 8-valve, compact) twin. It clearly reveals that the cylinder-to-head joint is higher than on the current engine when compared to the position of the front-engine-mount bolt hole. The engine mounts are designed to match those of the current engine, allowing the new version to be bolted into existing frames if required.


Detailed view of the LC8c. (KTM/)The increased height is reflected in the redesigned cylinder head. The followers that sit between the cam lobes and the tops of the valve stems are noticeably higher in relation to the top engine mount. The cutaway also appears to suggest that the current LC8c’s upper balancer shaft, which sits between the two camshafts in the cylinder head, may have been deleted in the new design, perhaps to keep the engine’s overall height lower. The upper balancer certainly isn’t visible in any of the images.


The new patent drawings seen here are focused on the redesigned oil-jet system that cools the undersides of the pistons. (KTM/)The new patent is specifically related to a redesigned oil-jet system, which squirts engine oil onto the undersides of the pistons to cool them down. The new design is intended to improve piston cooling and to simplify the manufacturing process. Instead of separate oil sprays for each piston, the KTM design has a single tube running parallel with the crankshaft with multiple nozzles pointed at the underside of each piston. As with other piston-cooling systems, the jets are focused particularly on the area of the piston underneath the exhaust valves, which tends to be the hottest area, but there’s also a second nozzle that sprays the area under the inlet valves.


This illustration shows how the oil jets are aimed specifically under the piston’s regions where the exhaust and inlet valves create the most heat. (KTM/)With more capacity, the next-gen LC8c is likely to have somewhere between 130 hp and 140 hp depending on its state of tune, and it’s initially destined for a completely redesigned “990? Duke. KTM has also been spied testing the new engine in a fully faired, road-going sportbike—the first from the company since the demise of the RC8 R superbike. The new model, likely to be called the RC 990, will finally give KTM a means to capitalize on its MotoGP efforts, and given the introduction of a second GasGas-branded MotoGP team this year, there’s also potential for the production model to eventually appear in GasGas guise.

However, the new 990 LC8c isn’t going to instantly replace the 890 and 790 versions. The 790 has only recently been reintroduced, both in KTM’s 790 Duke and Adventure and in CFMoto’s 800MT and new 800NK models, while the 890 is expected to be used in several forthcoming models including the 890 SMT that’s due to debut in April this year.