ASK THE MXPERTS: MORE THROTTLE RESPONSE FROM MY 450SXF

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mxpertthrottletubesKTM gives you two throttle take-up reels for the ODI throttle tube. The 450SXF Factory Edition comes with the gray reel, we run the black reel. Note the embossed “Inside” on the take-up reels.

Dear MXA,
I have a 2016 KTM 450SXF Factory Edition and I love it. The air forks are so much better than the forks on my 2014 model. However, I am interested in getting more pep at low rpm. It seems that when I exit a corner the power pulls very smoothly. This is nice because it makes it easy to ride, but I would like to get a little more pep in order to step up to the meat of the powerband sooner. What do you suggest?  Pipes? Fuel injection mods? Mapping?

350mapdial16To make the handlebar-mounted map switch work you have to set the map selector dial to the number you want. We run the dial on #2.

The obvious answer to your question is to make sure that the KTM map selector dial is set on position #2 inside the airbox and on the two-dash mark on the handlebar switch. This is the aggressive map. It makes the engine crisper and quicker than the stock map (which is any number other than #1 or #2 on the airbox map selector dial and the handlebar switch in the one-dash setting). The second suggestion would be to add one tooth to your rear sprocket. This livens up the feel in second and third gear and allows you to run third gear in many track situations. But, something that the MXA test riders do on the KTM 450SXF is to change out the throttle take-up reel on the ODI throttle tube. KTM makes two different size throttle take-up reels (and throws the one that isn’t installed as OEM equipment for your bike into the parts briefcase that your dealer gave you when you bought the bike).

There is a black reel and a gray reel. On your 450SXF the gray reel was installed in the bike at the factory, while the black reel is in the briefcase. The outer diameter of each reel determines how much throttle cable is pulled per rotation. The larger the diameter of the reel, the less the rider has to twist the grip to open the throttle body’s butterfly all the way open. This is called a quick-turn throttle. Conversely, the smaller the diameter of the reel, the farther the rider has to turn the throttle to get full power. At the KTM factory, the preferred reel is snapped onto the ODI throttle tube via the heptagon-shaped cutout. The 450SXF gets the small 36.5mm gray reel so that the abundant low and midrange power can be metered better, while the 250SXF gets the larger 39.5mm black quick-turn reel so that the reduced power of the high-rpm 250 engine can be accessed quicker.

However, most MXA test riders prefer to run the black quick-turn reel in place of the gray reel in the 450SXF. To install the quick-turn reel on your KTM 450SXF, disassemble the throttle housing to get access to the throttle tube. Remove the two throttle cables from the reel (pay attention to the cable layout and reel orientation). Pull the stock gray reel off the throttle tube and pop the black quick-turn reel on. All that’s left to do is reassemble the throttle housing, taking care to readjust the cable length adjusters. We leave a little more slack in the throttle cables with the black reel than we do with the gray reel. Here is what you will feel. (1) The tension on the throttle tube will be greater, which we like because it lessens minor throttle variations in the bumps. (2) Tthe power will come on much quicker and transition from the low-end to the midrange faster. In essence it livens up the low to mid powerband. (3) Since this is what you are asking for, and you already have the black part, you should try this solution first—because it is free.

Remember, black is the quick turn reel and gray is normal. We say this because we have gotten them confused in the past and in this months June 2016 “Ask The MXperts” column we transposed the colors.

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