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motocrossactionmag.com

ASK THE MXPERTS: WHAT DO KTM'S BUTTONS REALLY DO?

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MXPERTSmapswitchIf your kill button is on the right side of your KTM or Husky multi-switch, swap them. The kill button should be close at hand.

Dear MXA,
This year I stepped up from my trustworthy but old 2009 Yamaha YZ250F to a 2017 KTM 350SXF. The eight-year gap between when my YZ250F was new and today has brought about some marvelous advancements, but I am confused by the electronic switchgear on the left side of the KTM handlebar. I don’t fully understand what is going on when I press the buttons. Help.

You are not alone. Motocross bikes have come with optional ignition maps for years now, but accessing the maps hasn’t always been easy. Kawasaki and Suzuki use plug-in couplers (that the typical owner has trouble disconnecting or even finding). Honda has a button that activates flashing lights that signify whether you are in the aggressive, mellow or stock map by how fast they flash. KTM has had map switches that have been as simple as a wire you disconnect under the gas tank (250SX two-stroke), a dial that was tucked into the airbox, a flick switch on the right side of the handlebars and, for this year, the multi-switch. Yamaha does not have any map switches. When you add in the variety of launch control systems, confusion reigns supreme.

While KTM’s multi-switch was designed to place the map switch, launch control and traction control buttons in one convenient place, it does require a good understanding of what happens when you start pushing the buttons. Here is a quick explanation.

Map switch: Unlike last year’s KTM map switch, which was on the right side of the handlebars and allowed you to choose between two of three possible ignition timing maps (with one map always being stock and the second map being labeled mellow, aggressive or stock on a dial inside the airbox), the 2017 map switch only has two map choices (stock or aggressive). When you press the rubber-covered button on the bottom of the multi-switch, a lighted number is displayed on the face of the multi-switch. Number one is stock and number two is aggressive. Every MXA test rider chooses to run the aggressive map because it produces quicker throttle response and helps jump the power up to the midrange where it does its best work. There is no dial in the airbox to bother with, and, by the same token, there is no mellow map option.

Traction control: After you have selected between the two maps, you can elect to run traction control. Traction control has been illegal in AMA Pro racing for most of the last 30 years, but in 2015, the AMA changed the rule to read: “Non-production electronic devices designed specifically for traction control are prohibited.” After decades of banning traction control while doing absolutely nothing to enforce the rule in the face of escalating electronic ignition controls, the rule-makers quietly slipped the word “non-production” into the rule. Surprise! The 2015 Kawasaki KX450F was the first bike to advertise that it came with traction control as one of its new highlights. It was no big deal, because it was so innocuous that no one ever felt it. Honda put the same type of traction control on the 1997 Honda CR250, and the AMA never made a peep. If you read the new rule closely, you can see that aftermarket traction control, like the GET system, is still illegal. Yet, virtually every factory bike at an AMA National has GET’s system on it. You can be assured that regardless of what the new rule says, it will not be enforced.

Modern traction control works by having the ECU monitor runaway revs. Runaway revs are an indicator that the engine is free-revving, which means that the rear wheel is spinning. To stop the wheel from spinning, the ECU retards the ignition to slow the engine down and get the wheel hooked up again. To engage KTM’s traction-control system, you press the rubber-covered button on the top of the multi-switch and the letters “TC” will light up in the window. As long as TC is showing, the KTM 4560SXF is functioning with traction control. The MXA test riders only used the KTM traction control switch in places where they used last year’s mellow map—typically rock-hard, slippery or wet tracks. We found that when we engaged the system on a loamy track, it was a massive distraction and of little or no value. Thus, don’t think of TC as anything remotely resembling factory-level traction control systems but more like a third ignition map to use on hard-packed dirt or mud. It is really just a replacement for the now-missing mellow map.

Launch control: Last year a KTM rider had to cycle the flip switch on the right side of the bars back and forth until the indicator light behind the front number plate flashed. For 2017 the rider has to press the rubber-covered map button and the traction control button simultaneously until the indicator light behind the front number plate flashes. This is not easy to do in the heat of the moment on the starting line. It represents digital gymnastics that are tough to do with gloved hands. Of supreme importance is that once launch control is engaged, you must refrain from blipping the throttle. If you rev the engine up and let the revs fall by more than 30 percent, launch control will shut off, and you cannot re-engage it without turning the engine off.

MXA test riders rarely use launch control on dirt starts, but we use it all the time on concrete. Everybody has his own method for using launch control off the line, but the majority of MXA test riders hold the throttle wide open and dump the clutch. The retarded ignition curve knocks off several horsepower to decrease the chance of wheel spin. You should practice starts to find out how much throttle works best for you.

If you have a technical, political, emotion or historical question you want answered, send it to [email protected]

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