Spy pictures of the future KTM RC990 sportbike and KTM 990 Duke have been making rounds on the internet, so it is only right that they need a new engine. Well, that future seems to be confirmed with detail pictures of a new LC8c engine being leaked online.

While it would have been easier to just bump the capacity of the current 890cc LC8c powering the 890 Duke and 890 Adventure, KTM felt that it is better to heavily revamp, if not build an entirely new engine.

The LC8c (for Liquid Cooled 8-valve, Compact) parallel twin began as a 790cc powerplant. Its capacity was then boosted to 889cc via bigger bores from 88.0mm to 90.7mm.

(Picture above - new engine is on the left, current engine on the right.)

While there no official figures have been revealed yet, side-to-side comparisons with the existing engine show the engine to have a taller cylinder, suggesting a longer stroke. A stroke increase makes sense because enlarging the bores further will just move the torque curve further up... great for more maximum revs for higher maximum horsepower, but sacrificing low- and midrange punch and tractability - something which KTM street bikes are not synonymous with.

(Picture above - new engine is on the left, current engine on the right.)

The exhaust ports are straighter, too, to promote gas flow from the combustion chamber.

It is also evident that there are new crankcase, oil pan, cylinder head and transmission covers, along with a new oil cooler. The oil level glass is moved to a new spot on the clutch cover.

(Picture above - new engine is on the left, current engine on the right.)

Looking at the rendering of the new engine from the front or back, there is much space one side of the oil pan, suggesting a more snug placement of the exhaust's catalytic converter. Doing this ought to create more ground clearance, as well as centralising mass even better.

But of course, the biggest question among fans will be how much power will the new engine make? The current 889cc LC8c does 119hp so we may just see in the regions of 130-135hp for the new engine.

One more thing of note, the LC8c is actually built in the CFMoto factory, as per KTM and CFMoto's cooperation. Will the new engine also power a new generation of CFMoto bikes? That will be interesting prospect.

But in the meantime, let us look forward to the new 990 Duke and RC990.