I'm looking on behalf of a friend. We were travelling together but he's now off on the last leg of his trip and the bike is playing up rotten. While riding together it started "choking" as he put it. It was like the power was running out, an air blockage maybe or dead plugs. As it got hotter it seemed to get worse, stuck in traffic it would barely stay running. It cut out, spluttered, lost all power and then just died. We couldn't find anything wrong then it would start and run and then as it got hotter, it just did it again.
When we got to Bangkok it had a full service. They put it on the diagnistic and nothing wrong. I was suspicious but the bike ran fine after they cleaned it up, we hoped it was just a lot of dirt in the radiator. Now once he put the panniers on it did it again. At first we were stuck in traffic in bangkok so I thought maybe it was that but he swore it was the boxes. Possible I guess, they block airflow to the exhaust where the O2 sensor is.
Now he's right back to square 1. It's cutting out even when not in traffic. Once the weather cools or he drives in rain it gets better. He has bridged a circuit over the temperature sensor and said it helped a bit but only the rain and riding in the night when it's cooler keeps the bike moving.
Does this sound like anything anyone recognises? I'm not a KTM man and not familiar. Thanks guys.

Probably the fuelpump.

Interesting, other people are telling me this. Is it a typical problem with these?

Hola amigo

I am now in south america and had exactly the same problem.
read a lot in forum and many people try simply to say it is the fuel pump.
This is expensive.
So I got from KTM in Santiago the Chile a fuel filter set.
Most importend is the intake filter of the pump. It looks like a tee bag.
When this is clogged the bike behave like this.
since I changed the filters (the are 2, intake and outlet) the bike is running fine.
There are also excellent descriptions on adv rider. Look after fuel pump 990

good luck....

Fuel pump.

As heats up, pump malfunctions and output drops. Does it happen as tank gets lower in petrol (used for cooling the pump)?

Similar symptoms to F800GS issues.

I can't answer very specific questions as it isn't my bike but it did do it with a full tank and then we lost a lot of fuel investigating the problem and it was still bad. It didn't do it so bad the next day after filling up and riding while it was cooler. It was far better through Nepal too but it was cooler in the mountains.