Duke 390 with random bouts of 0 throttle response

**Asymptomatic** · 06-30-2016, 03:19 PM

Hello everyone,

I have a KTM Duke 390. For some reason and I am not sure why, at random times I will give the bike throttle and it does nothing. It is like the throttle is not connected for a moment. I release and try again...it works. It seems to be happening more and more often. Cruising down the road, slow down for a moment, go to pick up some speed and 0 throttle response. Let the throttle go, try again and it works.

Any ideas?

**zhu** · 06-30-2016, 04:12 PM

Its fuel injected

**ShuBen** · 06-30-2016, 11:50 PM

The EFI flap or the actuator itself hangs sometimes. Might be a mechanical problem like corrosion at the flap axle or an electrical unstable connection.

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**Asymptomatic** · 07-01-2016, 01:54 AM

It is a new bike so it must be mechanical... sigh the dealer is a 7 hour trip away.

**Zorge** · 07-01-2016, 10:19 AM

Those damn fly/drive/ride-by-wire systems!

My mk.3 "Maggie" have e-throttle and I hate the damn thing. I have feeling that my right foot doesn't determine engine revs.

If you manage to solve this problem with different throttle response and you are still not content with throttle progression, you could fit some jetter or do some throttle body "trenching" (Gadgetman groove).

**Asymptomatic** · 07-03-2016, 10:06 AM

Someone local made the suggestion that because it is a 13 to 1 compression ratio that it might be the 97 fuel I'm using. That it needs better fuel so sometimes it misfires when the throttle is pulled and feels like it's dying out.

What do you think?

**zhu** · 07-09-2016, 02:24 PM

Well 97 is the best you can buy so there is that. Efi usually has a detonation sensor so I don't think fuel octane is your problem.

13:1 is pretty high though so I hope the det sensor does its job.

**TexasAggie** · 07-09-2016, 02:54 PM

As Zhu says, 97 is the best you can buy here unless you have access to aviation fuel. We ran into the same issues on Baja race bikes in Mexico years ago and used a fuel additive to boost the octane. I have no idea what is available here in the middle kingdom but if there is something, it might be a cheap and easy test to see if it helps....

Just throwing ideas out....

**Asymptomatic** · 07-11-2016, 05:24 AM

As a test I ran my tank dry and tried 95 fuel. The problem was significantly worse. I put 97 back in and the problem was like it has been. So, now I have ordered some fuel additive like Texas suggested to see if they help. My manual for the bike says 99 or higher. Insane...

I still love this little bike though!

**Mot** · 10-18-2016, 06:14 AM

Interesting... 95 octane is the highest available in my area and I ran it all season with no problems at all. My Duke 390 is a 2015 though, so no drive-by-wire. Did you ever find a resolution?