Patent filings emerge of new 990cc KTM LC8c engine

The KTM LC8c engine is slated for a major overhaul, according to patent filings made by KTM's Chinese partners at CFMoto.

Launch 2022 890 DUKE R

Patent filings have been made for a new version of its LC8c parallel twin-cylinder engine. 

KTM’s LC8c platform has been around for a while by now, since its original arrival as a 799cc engine. It was then expanded for the newer 890 range of motorcycles, and is now undergoing an almost complete overhaul in order to expand to 990cc.

The new engine has already been tested in both a proposed 990 Duke, as well as a highly anticipated RC 990.

Only now, though, have patent images emerged of the new motor, which have been published on BikeSocial.

The current version of the LC8c - that being the one found in KTM’s 890 range, for example - required significant changes to allow it to expand further to 990cc, as this Twitter thread from Martin Fitz-Gibbons explains, thanks to the measurements of the engine and in particular the proximity of the two cylinders and the thickness of the wall between them. 

As a result of the existing engine’s incompatibility with a further 100cc expansion, KTM went to town with the LC8c to bring it to close to one litre.

BikeSocial reports that only the water pump lid, ignition coils and throttle bodies are carried over from the previous version in this 990 edition.

One of the ways in which KTM has found increased capacity in its LC8c is by increasing the height of the cylinders, which has been matched with a shortening of the cylinder heads in order to allow the engine to keep the same dimensions. A result of this is that the engine mounts are the same between the new and old LC8c, meaning KTM - or Husqvarna or CFMoto, for example - could place the new engine into the chassis’ which housed the older, 890cc version. 
Increasing the height also allows for a crankshaft with a longer throw, as well as a longer stroke.

Meanwhile, the transmission is changed, although similar, compared to before, with the major changes being in the cases and castings.

Elsewhere, the changes are more significant, with a new, enlarged oil cooler, and larger exhaust ports to before, while the transmission casting is now smaller which is most likely a choice made to enhance the packaging of the bikes the new engine will be fitted to.

BikeSocial also notes that the patent filings have been made by KTM's Chinese partner, CFMoto, who use the 799cc version of the LC8c in their 800MT. It would be reasonable to assume that they will take on the responsibility for the construction of the new engine.

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