Business as usual for this SM’s ECU remap (and owners of all the 990 KTMs are queuing up at the door for the same) as the request was simply “Make it more rider friendly!”
And it’s the same old story for all of ‘em – the emissions control of the engine is overpowering the bottom end power delivery leading to rough-feeling running. We start by switching off the lambda and SAI, and map the fuelling to suit whatever can or air filter (or nothing) is on board. We remap the fuelling in two areas; the MAP (Manifold Air Pressure) table and in the main running table. The MAP table is critical for on/off/on-throttle running, which is why it needs the time.
We also remap the secondary butterflies. Now we know ‘the internet’ would have you believe that they can be simply binned but this is not the case. They are there for a reason – this is a big V-twin with a big intake and at low rpm the gas speed is virtually zero. To make the engine pull cleanly closing the secondary butterfly increases gas speed. And when you can map it, why get rid of it?
The ignition map is an area we look at more and more, and with every bike we do we make tiny improvements. KTM, as part of the emissions control run big advance in the bottom end; on a closed throttle it has time to purge the cylinder. This in its self causes issues, which we can alleviate in the map. The secondary effect is on closing the throttle (say from 60/70mph) where the bike stops dead, like an anchor’s gone out the back – we can soften this feel through the ignition.
The irony, of course is that everything we do makes the fuel-injected 990 motor have the character of the old 950 carb’d engine…