Some bikes are suffering from a faulty Brake Light Switch sensor, usually the rear one. If the stop light is permanently turned on, this is likely the culprit. The fix is to replace the sensor under warranty, they are just defective from the factory. This requires removing the fuel tank.
The sensor seem to be self-calibrating, as such some stop and go action sometimes recalibrate the sensor and the problem fixes itself.
Push come to shove, replacing the switch is relatively easy (you just need to remove the fuel tank to get access). See this post on advrider by AdvRonski. The switch itself is even available on Amazon (but will require a bit of soldering to adapt the connector, so prefer the KTM part: front p/n 64111051100, rear p/n 62111051000, the only difference between the two appear to be the connector).
A faulty Brake Light Switch sensor will cause the Cruise Control to disengage, not set, or not resume.
There is a condition that shows a full fuel tank but the engine sputters and eventually stops … you’re out of fuel — sort of.
If either the left or right fuel cock is closed, fuel will not balance out between the two lobes of the tank. With the fuel pump on the left and the fuel level sensor on the right you get a full indicator on the dash (because the right side is full) and a pump sucking the left side dry.
Both fuel cocks need to be closed to remove the tank. If your shop or you forget to reopen them expect to run out of gas early. (Mine came from the dealership with the right side closed.)
Luckily each fuel cock can be accessed and opened or closed without tools or removing any parts — the left side more easily than the right.
On the left, duck your head under the fuel tank and you’ll see the knurled knob right there. Turn it counterclockwise to open.
On the right you’ll have to jam your had under the tank lobe and feel around.
The blurry clip on the right side of the above photo is the electrical connection to the fuel level sensor and is easily visible. The fuel cock is further to the front and more difficult to see.
If you can’t reach the knob, find someone with smaller hands or remove the right side tank guard. Again turn the knob counterclockwise to open.
Here are a couple screengrabs from the R repair manual for further reference. The first picture is the right side, second is left, and third is right again.
There has been a few clutch failures, at fairly low mileage, and the people affected have been quite vocal as very few of the failures have been covered by KTM. The numbers of failures is however very very low. Since I wrote this article, in November 2019, the number of clutch failures stayed really low. There were 6 known at that point, and this number didn’t even doubled since then. At this point this is a very rare occurrence. I’ll update this article if I receive more updates.
Reports of failures
The main post triggering the attention to the issue was Quintin Mclaughlin’s report: he had only just run the bike in and had the initial service before setting off on a road trip through France, Spain and Portugal. Clutch failed at only 2,000 miles (3200kms).
On the comments on this FB post there are other report of failures: Uli Schildt picked up his bike in Arizona and rode 3,000 miles back to Washington State. A week later his clutch failed.
JP De Villiers, still on the same FB post, writes, “After my first clutch burnt and the fault was put on me after only 2700 km. I put a [heavy duty] Rekluse torque drive with the hope it will be a stronger replacement. It took exactly 300 km, clutch started taking high and slipping exactly like before.”
Those were simple failures, where replacing the clutch plates and the spring was enough to go back on. Unfortunately some riders experienced more catastrophic failures requiring a 3k “rebuild of the engine”. Bill Cairns was the first one, but Yevhen Karel described a similar failure on this FB post : “the clutch plates were burnt, broken into pieces. Then clutch powder blocked the oil filter, oil pump, etc. and the oil could not circulate as it should (the oil could not be seen in the check window). As a result, some oil has been found in the exhaust. Now the engine needs to be rebuilt, cleaned and new clutch to be installed”.
There is another report from Mark Ferbrache’s of a failure at 9000 kms, still on the same long FB post. But in this case note that Mark uses the clutch a lot: “[offroad] you’re on the clutch the whole time. Plus if you’re on a really narly climb your going to be on the clutch a lot“. As opposed to a small trial bike, slipping the clutch all the time on a big adventure bike is going to cook it in no time.
Alarmed by the news of clutches failing, windblown101 decided to open his, just to check, and found it in working order. He still changed the springs as they were slightly out of spec. So here you go, pics of a good clutch.
I leave the last word on this to gearheadE30: “Clutch failures (unconfirmed). Probably similar to range of experiences people had with 950/990 clutches. From what I have seen, most of these failures have been from abuse. I have only seen one that actually looked like a surprise failure, which appeared to be due to insufficient oil flow. The outermost clutch few clutch plates and fibers didn’t seem to be cooling adequately and showed obvious signs of heat. Seems to be fairly uncommon but we may see that the “meoni clutch mod” from the 950/990 becomes a popular change. One also looked like clearance between the input shaft shaft ID and the clutch release “tension bolt” part number 63532048104 was maybe too tight and not letting oil through to lube the clutch…but that was just from looking at wear patterns in pictures so it is hard to say. I’m calling this an open question, but it’s worth saying that the clutches held up great in Morocco and the only problems we had were due to unusual abuse“.
What we know about the clutch
The clutch on the 790 is a wet design, but instead of just dipping in the oil a feed is also injected via a jet in the center of the clutch shaft. This jet is on the worklist of recommended work to be performed at every service (See the Service manual, page 414). Note that this is not a new system for KTM, the same overall design has been present on older models like the 950.
Some believe that those failures are due to the jet being blocked by debris in the oil, preventing lubrication of the plates and causing an early failure of the clutch. A KTM dealer even diagnosed it as such. There are suggestions to increase the jet size, and/or drilling holes in the basket, but those are not proven to actually work (The fact that it worked on the 950 16 years ago, doesn’t make it the panacea for a brand new bike). Plus increased oil flow will make finding neutral more difficult.
See also this post with good information about pressure and the size of the hole.
The #1 recommendation is if you feel the clutch slipping, stop ASAP. From first sign of slippage to unusable bike seems to happen in a very short time.
Check the freeplay. Often. Lack of freeplay at the lever will cook a clutch fairly quickly: make sure to control it (procedure is in the manual). For those using a CamelADV extender, to keep the same freeplay on the clutch you need to make the freeplay on the lever a little longer.
Finally when the traction control intervenes and leads to the engine bogging down it’s important not to slip the clutch to raise revs, instead you should leave MTC to do its job.
The clutch is a wear item. As such, like brake pads or tires, those failures are not covered by any guarantees, including the KTM one. For this reason none of the failures above were covered, to the dismay of the owners.
Some believe there is a technical issue with the bike causing the early failures, and if it is the case, the clutch should be changed free of charge, along with the cleanup job to remove bits of clutch material from all the oil passages.
I was kicked into gear into writing this article thanks to Tim Cullis. He posted another great post on an UK forum, which served as the original base for this article.
On the R, and only on the R, there are reports of rear shocks failing and needing to be rebuild. It’s hard to figure out hard numbers, but there are a few. Just to be clear the issues are of shock leaking oil, broken seals, not broken shaft or “exploding shock” as you can read online.
There is a theory going around incriminating the catalytic converter: it is really hot, and very close to the shock, so it is possible that it is heating up the oil or the seals, thus causing the failure. Some facts however don’t align very well with this theory:
This failure is only on the R, the S model is not affected at all. If the catalysts were in fact “boiling the oil inside the shock” as I’ve read it in place, there would have been failures of the S shocks as well;
There is at least one example of a failing shock absorber on a bike with the catalyser removed from day one. Ergo, the catalyser in that case was not to blame;
As bikes get more mileage, failure rate should have increased. This is not the case, the bikes with failing shock absorbers are all low mileage (less than 2k, very new).
This seems to indicate that the issue is probably not the catalyser but more likely a default on some shocks with a problem from the factory.
[If you have a 2020+bike, don’t worry, these are now coming with some threadlock from the factory]
Check the screws linking the gear knuckle and the gear linkage. It has been reported multiple times that these screws like to fly away. There is nothing to stop the screws from unscrewing, and no thread locking from factory. Remove those bolts and use of a thread-locking liquid before putting them back (Loctite or equivalent).
The manual list the torque for those bolts at 10Nm (7.4 lbf ft), and the use of Loctite®243TM or equivalent (Page 333 of the R version of the manual). Do not overtorque “for safety”: the knuckle is aluminium, over torquing will destroy the threads.
Bikes were reported to leak oil on the rear left side. For most bikes this is not a leak: this is chain lube. It collects in the pinion cover and runs down the engine. The chain out of the factory is coated with a very fine oil that is very liquid when warming up. As long as you don’t see the oil level decrease in the engine just forget about it and ride.
But is seems that a small number of bikes may be affected by a leak from the oil sump gasket.
In the pic below you can see a loose rubber grommet around the wire going to the side stand switch (you can also see it in all the pics in the chapter on oil leak). One might think that this grommet should be stuck somewhere protecting the wire. Well, it turns out it is not, this is a superfluous grommet with no purpose whatsoever, probably because the same part is used on another bike where it is needed.
Just ignore it. Or cut it and remove it to gain a few grams…
Happened to a few bikes, panel replaced at first service. On some bike this made the panel die completely. Those panels are probably not fully waterproof, air inside expand and escapes when hot, and then fresh air is pulled from the outside when temp is cooling. This fresh air condenses, creating the fog.
As I write this (April 2020) KTM has stopped replacing the faulty panels, there is an announced new model to replace it, dealers have been told to stop replacing them and to wait for the new part instead.