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450xcf Update – Throttle Position Sensor Issues
KTM 450xcf throttle position sensor
We are up to over 2,000 miles on the 2014 KTM 450xc-f test bike now. I have completed most of the modifications that were on the list. Frankly, the flywheel had such a positive effect on the motor, I now ride the bike everywhere.
We are three full years into riding KTM fuel injected bikes constantly and all without issue. I am to the point of almost hoping for a problem just so I can spend the time to diagnose the issue, fix it and then figure out how to make sure it does not happen again. Of course, on the other hand I have no desire to find myself stranded in the middle of nowhere with a bike that won’t run.
Well, either way, I thought I was finally on to something. The 450 started running poorly two weeks ago. It became hard to start, stall prone and would not idle well. Finally, I have a problem to look into! Surely this is the much talked about clogged injector. After all, I have been running Pemex in the bike and that can’t be the cleanest stuff. Or maybe the in line filter has clogged. Or maybe it is some other mysterious electronic gremlin.
Normally I would haul the test bike back to KTM and have them figure it out. But in this case the crew at KTM were swamped and I really wanted to take the 450 for a ride I had planned. I was talking with RJ at All American KTM and he suggested I run the bike over and he would take a look. Since he is close and I was tight on time, I decided to do so.
We fired up the new version of the KTM XC1 diagnastic tool. It is a tablet that uses a blue tooth connection to the bike, no wire needed. After a quick run though the regular diagnostics, everything tested positive. Hmm, that was no help. Next he said we should take a look at the TPS value. It is a specific number that tells the setting of the sensor.
Sure enough, the value was way off. If you are not familiar with the KTM TPS sensor, it is an external mount and has a set screw that allows it to be manually adjusted. It is pretty much the same as the one on the older pumper carbs. Within just a few seconds RJ was able to readjust the sensor position and have our bike running in the pink.
Because the sensor has just one screw to hold it in place and it is rotated manually to adjust, it is probable that I hit something to knock it out of position. Later I realized that we had somehow lost the plastic cover that protects the sensor. So yes, we finally had an electronic issue, but it was probably due to an impact with a stick or something.
Fortunately our fix was easy and required no parts. But without the diagnosis of the XC1 tool, we could have swapped parts out forever and never figured out the issue. I imagine many would have just put a new injector in, or worked on the fuel pump etc, none of which would have helped.
I have one other small item to relate. One of my riding buddies purchased a used JCR Honda race bike, a full race spec CRF450x. He was excited to show me how good it was. Yes, the Honda has some great suspension on it. But in standing start and roll on tests, our 450xcf beat it handily. Starting in second gear, the xcf had a full bike length lead by the time we hit third gear and then could keep that all the way through the gears. In addition the xcf has considerably better bottom end.