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KTM SMT 990 ECU remap

By 31st October 2011ECU Remap, KTM, Road Bikes

A completely stock, but well and properly used, KTM SMT 990; the owner booked it in for an ECU remap, as he was finding it difficult on fast, flowing roads getting on and off the throttle smoothly. Also when braking hard, the transition going through open-to-closed-to-open throttle was not good, and the engine ‘hunted’ in traffic badly – to be fair all of these symptoms are fairly standard on the KTM’s big V-twin engine.

With all of these ECU remaps we make a point of riding the bike as it comes in, and when it goes out. This SMT was quite bad; first job was to plug into the ECU and download its map so we could get to work. Switching off the lambdas was first (we’d rather remap to open cans, but they can be left in place) but we didn’t fuel it as heavily under 4,000rpm as we would to protect the cats. The owner of this bike plans to replace his stock cans at a later date, so this is a short-term situation anyway.

Next up were the secondary butterflies, which do have a major impact on how these bikes run. You can’t remove them completely, but we modify the map to open them earlier. There are four main fuel maps, four Manifold Air Pressure maps and five ignition maps to adjust so there are no quick fixes here. Looking at the ignition map of this particular ECU we could see things that simply weren’t good for a roadbike ridden in general road situations; from an outright performance or race perspective it may be good, but not in the real world. We spent a lot of time in this particular area of the map, in order to deliver much more on/off throttle civility and useability.

The owner wasn’t interested in extra rpm, so we left the limiter set where it was stock. Riding the bike after the work had been done showed a noticeable, and very positive, difference; it had gained midrange power thanks to the tailored ignition map and the sharp, harshness of the power delivery was smoothed.

You don't have to modify a bike to benefit from an ECU remap – this SMT was transformed.