Letter Of The Week: Gearing Up For A KTM XC-F


Regarding your article 2017 KTM 450XC-F:
I am riding only in sand: Fast open and narrow winding sand trails and also in sand dunes. No dual sport. No track.
My current bike is the 2017 KTM 500 EXC-F.
I am really enjoying riding it.
After reading your article I am considering upgrading to the 2017 or 2018 450 XC-F mainly because it is 17 lb less heavy which is incredible!
I would add a front light and I would switch transmission and put a 6 speed transmission on it even if I have to split open the engine block!
You said: There is plenty of power to do both but not through the stock transmission ratios. We’ve never hated a six-speed gearbox in off-road bikes but maybe even a wider ratio spread in this XC-F would be better at everything but the track.
I checked on the diagrams and both bikes (XC-F and EXC-F) share the same engine block and clutch.

Do you know by any chance if the transmission of a 2017 500 EXC-F could be fitted? Or any other bike from KTM with 6 speed? Any suggestions?

Anybody has done it?
Also is it possible to install a front light? Less important.
I would also listen to your advice if you tell me to keep the 2017 500 EXC-F!
Many thanks for your help.
Actually, for riding in sand, you may not have to do anything. Or it may be as simple as changing a sprocket or two. You are correct and you could swap out the gear set (and shift drum) from the 500 EXC and have that transmission and spacing. You could even just add a sixth gear to what you already have in there. This would take a little more thought about the ratios and also require a shift drum and maybe shift forks.
But our experience in sand riding is that you do not need a really low range ratio for first gear since you are always spinning. The 450 has plenty of power to pull an even taller gear than first is already. We were having issues with the “range” of the transmission. What we wanted was a taller and faster fifth speed but we were not willing to raise the ratio of first. In our more technical stuff the clutch just does not like the abuse of going slower than first gear’s ratio. In sand you should only use the clutch as an on-off switch, after all the rear tire is already spinning, why would you want the clutch to be slipping too?
I think for sand–especially the chassis and suspension–the XC will be a huge step up, not to mention less weight. I would personally try dropping a few teeth off the rear sprocket or maybe even going up a tooth on the countershaft and just try that. The more racy nature of the engine and its willingness to rev might just be enough to where you will not need to change anything unless you want to go over 100 MPH.
For the light we have had excellent luck running a Baja Designs Squadron and even better results with a Moto Minded setup. These are as simple as running a set of wires from the battery.
Good Luck and let us know how it goes.
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