Engine randomly cuts out after certain rpm

[Hank Marvin]

Hey all, just wondering if you guys can chime in on this weird issue with the 990R, 2009. I tried searching the forums, don't know what keywords to use..

Everything always runs fine off the bat, loads of grin when the throttle cracks open
After a short ride, say 30min, sometimes the engine would continue to rev up to about 6,000rpm, then suddenly loses rev/power as if the throttle was closed.
It then jerks around 6,000rpm like it was hitting a crappy rev limiter.
Backfires? I don't quite remember. SAS still in.
This happens in at least gears 1-3, haven't tried other gears.
The bike runs fine under 6,000rpm, no power loss or anything.
After I keep it civilized for a few minutes, and try opening the throttle (both smooth and WOT) again, sometimes it's fixed, sometimes it doesn't.

Weird thing is that it has happened once before, and virtually useless straight from idle. After parking it for 10-15 minutes, the engine screams again.


I'm guessing a dirty fuel filter can cause this, as debris slowly clog it up, but when parked/lower rev they'd fall off the filter. Not likely to be electrical, because everything still works under a certain rpm.
Running too rich perhaps? But it's a fuel injected bike, and doesn't happen for the first little while.

[Deuce]

Fuel filter.

[Hank Marvin]

That was quick, thanks! Good thing I've got a spare fuel pump rebuild kit ... somewhere in the shed

[TheMuffinMan]

Originally Posted by Deuce

Fuel filter.

What he said.

[Hank Marvin]

First time cleaning a fuel pump, and 10,000 dead brain cells later:



The new filter was too tight, a 9/32 socket was just the right size. Heated it up with a torch (faaaar away from the petrol fume), melted a bigger hole, and it fit perfectly!

[Head2Wind]

I would also verify that all of the connectors on the lower left of the engine that are associated with the side stand switch, gear selection and one other that I can't remember off hand, are all clean and seated 100%.

I just fixed a 950 SE with a intermittent running problem and it was related to the one of these three connectors being filled with silt and electrical connections failing.

Disassembled (unplugged) all of the connectors, sprayed with contact cleaner, blew them out, packed with dielectric grease and reassembled. Issue resolved... after of course going through all of the other connections and ignition switch.. etc. Worth the effort while you are in there with the tank off for sure as a matter of prevention even if its not the core issue.

[gefr]

Originally Posted by Hank Marvin

The new filter was too tight, a 9/32 socket was just the right size. Heated it up with a torch (faaaar away from the petrol fume), melted a bigger hole, and it fit perfectly!

The new strainer filters have the inlet hole too small at 10,5mm while it needs to be 11mm. KTM needs to adress this.
Cheers.