Duke 125 doing my head in

[sgtbash]

Bought my first bike - 2017 Duke 125 just to get me by while I get my MOD 1 & 2 done.

Lovely bike, only 6k on (now) however it dies when revved in gear and cold - it will do whatever you ask for it in neutral, knock it into first (or whatever gear) and itll idle fine, until you rev it (which it will) and then instead of returning to idle will just die.

I gave it a full service with correct oil etc, new spark plug etc but still the same.

Its better when warm, but after revving will go to a very low RPM(500) before returning to a normal idle after being revved.

The clutch has been properly adjusted, and is not dragging.

Any thoughts? I'm stripping the throttle body down and giving it a good clean soon!

[jjones]

Friend bought a nearly new one of these and the dealer had stolen the coil pack off it for another duke 125 with issues. Might be worth a google as it might be a common fault.

[trickywoo]

What did the old plugs look like?

Sounds like it could be running crazy lean or rich. The old plugs, or even the new ones run for a while may indicate if this is the case.

[jjones]

Quick google
same issue , never resolved: https://www.reddit.com/r/KTM/comments/2bejs4/issue...

Searching this forum for "cutting out" gives a lot of hits! https://www.ktmforum.co.uk/

[sgtbash]

jjones said:

Friend bought a nearly new one of these and the dealer had stolen the coil pack off it for another duke 125 with issues. Might be worth a google as it might be a common fault.

Great! Never through of coil pack honestly, as it's fine when revved in neutral

trickywoo said:

What did the old plugs look like?

Sounds like it could be running crazy lean or rich. The old plugs, or even the new ones run for a while may indicate if this is the case.

Old plug was fairly white, how can I adjust the fuel mix on one of these direct injection motors though!

jjones said:

Quick google
same issue , never resolved: https://www.reddit.com/r/KTM/comments/2bejs4/issue...

Searching this forum for "cutting out" gives a lot of hits! https://www.ktmforum.co.uk/

I have spent a solid 6 hours googling and have yet to see any post with my exact problem have the issue resolved!

[leighz]

could be fuel starvation. Plug colour might give you a steer

check fuel pump works properly

clean fuel filter

[trickywoo]

sgtbash said:

Old plug was fairly white, how can I adjust the fuel mix on one of these direct injection motors though!

Find someone to measure the AFR to know for sure but if it is lean at least you know where to start looking.

Could well be a fuel pump / injector problem.

[Benni]

If the white plug indicates lean-ness, my usual suspects would be (blocked) tank ventilation,

or sucking unwanted air into the intake way.

Open tank cap slightly, better if not filled to the brim, see if engine runs better,

and spray the intake / throttle body area with brake cleaner while idling, if the revs change while doing this,

there is a leak in the system allowing more air in than intended.

[KTMsm]

I have no 125 knowledge but on my 690 duke it was unrideable below 4k - a Kev XTX O2 "correcter" made a world of difference there were also O2 delete / resistor options which made it even richer

The other option would be to raise the idle speed - I'm unsure if Tune ECU will work on your bike

[Biker 1]

KTMsm said:

I have no 125 knowledge but on my 690 duke it was unrideable below 4k - a Kev XTX O2 "correcter" made a world of difference there were also O2 delete / resistor options which made it even richer

The other option would be to raise the idle speed - I'm unsure if Tune ECU will work on your bike

I understand that this type of bike is essentially a closed feedback loop type system to comply with emissions etc.
My 2p worth: lamda sensor either dirty/knackered or wiring issue.

[fred bloggs]

They are only marginally better than Chinese bikes, these.

My guess is idle control valve dirty.

[sgtbash]

fred bloggs said:

They are only marginally better than Chinese bikes, these.

My guess is idle control valve dirty.

Yep I've realised! Load of Sh*te

I stripped the throttle body down and ave it a good clean, major service, fuel filter, tried adjusting for higher idle, tested clutch I can move it in gear with clutch in. Still does it.

One of the exhaust clamps was fu*ked, bought a new one and did it up as it seemed to be blowing.. still the same.

Never buying KTM again even if the bigger bikes are built better.