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Fixing poor power and lean condition

23K views 37 replies 8 participants last post by  A.J.s Duke 
#1 · (Edited)
I've got a 2013 Duke 690, third owner. So far this is what I know about the bike:

10k miles
Stock airbox + filter
Stock map
Yoshimura R-77 slip-on, Fresco decat
Stock camshaft
15/42 gearing

The bike will only power wheelie in 1st gear using either the performance or standard map on the under seat switch. Even then it only comes up a little, and I'm not a heavy rider: 70 kg.

I managed to hit 100 mph while laying on the tank with the throttle pinned. I could likely get it to 105, but no more. There was some cross wind but nothing serious. I don't care about obtaining more top end speed and am only mentioning this for the data point.

With the 15/42 sprockets and the standard map on the under seat switch it feels quite good and smooth around town. 8 mph in 1st and 15 mph in 2nd are smooth, and up from there. Problem is, if I whack the throttle open while the bike is under 3k it will hesitate. I don't like that!

It also surges slightly (this was more pronounced on stock gearing, even more so with the performance map selected) between 4.5k and 5k RPM.

The bike will sometimes stall if I'm approaching a stop in 2nd and clutch in while letting off the throttle. Also the idle RPMs aren't stable. They're not hunting too seriously but if this was a carbed bike I'd be messing with the idle screw and floats to get it steady. It makes me think it's trying to stall itself while idling, but it never does so I don't worry too much.

It sounds like Chinese New Year when decelerating or engine braking down the long hills in SF. pop pop pop pop pop pop pop...


I really enjoy the power and feel of the bike and don't expect more from this engine. However I want it to be smoother and snappier, and I'm worried about upsetting the engine by running it lean. It gets HOT some days.

Should I:

1. Get the Akra map flashed?

2. Get Kev's fuel mod or an equivalent resistor-based hack?

3. Improve airflow via better air filter and/or airbox mods?

4. Get a Power Commander/Bazzaz/other piggyback fuel controller?

Side question: Would running the Akra map with the stock cam risk damage to the engine?
 
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#4 ·
That's great to know about the map.

The cam interests me as I'll be checking valves soon and while I'm in there, might as well swap cams. However in North America the EVO kits appear to have been recalled or discontinued. There was a thread on here a few weeks ago about that and now I see KTM Twins has the airbox + cam kit unavailable. I suppose I can just get the rally replica cam, but that sounds different than the EVO/KTM cam, is it the same one?

https://ktmtwins.com/products/ktm-76012945050


I've had a stall yesterday and today, the frequency is worrying since in the past it has happened *maybe* once every week or so and I could attribute most of them to something I did with the throttle while clutched in. I bet it has to do with the warmer air as summer is coming. Not that it makes sense. Warm air should be less dense therefore encouraging a rich condition, right? Bah!
 
#3 ·
I've done 1-3 with good results. I'd get the DNA 2 filter/side cover and leave the stock one on place.
 
#6 ·
That's interesting, KTM Twins has that part as https://ktmtwins.com/products/camshaft-cpl for $214, very similar pricing to KTM Parts Pro.

They also have that same part with -rr (Rally Reid?) appended here https://ktmtwins.com/products/ktm-690-cam but that's $265.

I think I'll give them a call and see if they have any idea why the price is different and if the -rr designator on the part number is a different part or is only for branding.
 
#8 ·
Question - can a map fix the loss of low end power that comes from installing a full system sans cat?

I just installed a full arrow system on my '17 duke + PCV with the dynoworks map for 'Full Arrow System Standard Air Box'. The fueling is now butter smooth, but definite loss of low end power. It does still have a nice top end hit now, but previously could power wheelie easily in 1st and 2nd, now only in higher RPM in 1st.
 
#21 ·
NO, it doesn't work with the newer engines!
Last engine that function with this solution is 690 Duke 3R (-2011), 690 SMC-R (-13)

The new throttle body starting from 690 Duke 4 (2012-) / 690 SMC-R (2014-) and also all Husqvarna 701 haven't the possibility anymore to adjust the TPS! :.( Damned!
 
#22 ·
Thanks for the advice - too bad it won't work.

I'd like to expand on the conversation. It sounds like if the bike is lean, the fix is mapping.

But my questions is - what can be done after putting on a full system to improve bottom end power? That is, what can be done to compensate for lost back pressure of a cat?

That is, is mapping the solution? Or, do air box modifications help too? Or something else? Note that my bike is '17, so the racing cam is not applicable.
 
#24 ·
Any idea if opening up the airbox (drilling/cutting or buying the precut KTM one) risks allowing water into the airbox? I won't be doing river crossings on the Duke but what about riding in heavy rain, or letting it sit outside uncovered during a rain storm? Water ingress is my only concern with airbox mods.

The stage 2 filtered airbox side cover doesn't allow water in from what I have read. That's another option.
 
#27 · (Edited)
Sorry haven't the time to translate everything in English

Just read this two threads. I put them in Google translator.
And yes it is worth to sign in at Europe's largest KTMforum also it's German language

690 Duke 4: Tuningküche reloaded - Duke-IV Stage-II

690 Duke 4: Tuningküche reloaded - Duke-IV Stage-III

And this:
Airbox water drainage
Due to the now created holes in the "unclean" area, water can get into the airbox when washing – not by rain.
But there is no hole in the unclean area!
You should drill a drain hole: see pictures!
 

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#29 ·
Ha that's funny, I just spoke with him at length too and he told me the same things.

That's a ton of money for tuning though :/

I'm certain it's worth it but it's tough to pony up vs. settling for autotune.
 
#33 ·
I bet an R would act like that, but here in the US we only have the non-R versions meaning we lack the better pipe, better airbox, better cam, and better mapping (among other things like suspension).

I'm inching closer to modding mine like the R but so far I only have the pipe without the airbox or mapping, so it's running too lean for optimal power, plus the loss of backpressure (due to a straight through exhaust without a db killer/baffle/silencer in the muffler) causes some torque loss at low RPMs.

You all have it quite good with your R models out there :smile2:
 
#35 ·
I bet an R would act like that, but here in the US we only have the non-R versions meaning we lack the better pipe, better airbox, better cam, and better mapping (among other things like suspension).
airbox, cam and mapping is same non-R vs R
 
#37 · (Edited)
Doing a 15 min reset on a cold day helps make the bike peppier all around, but it's still not perfect.

I've removed the SAS and canister, using a SmartMoto blanking plate (eBay) and the Rotweiler dongle + throttle body plug.

This has cleaned up my engine area, lessened weight, added extra room under the passenger seat, and most importantly nearly eliminated popping on deceleration!

I've done the valves and found an intake to be on the tight side and an exhaust to be on the loose side, both at the limits of the spec. Now all valves are in the middle measuring 0.10mm gap.

I also installed fresh spark plugs to replace the beat ones that I'm sure were original (11.5k miles) and sprayed the coils with contact cleaner.

This made the engine quieter and less rattly, smoother, and more responsive. Very happy with the results.

Finally I had the hole in my Fresco decat welded and that not only makes the bike sound better and less rattly but I think it also improves throttle response ever so slightly.

The hanger tab on the decat got ripped off the pipe, leaving a ~1cm diameter hole in the pipe. No idea how it happened, I bought the bike that way.

The welder noted that the metal around where the hanger attached was thinner than the rest of the pipe. Manufacturing defect perhaps? He filled the hole and laid down some steel around the area to reinforce it when the hanger was reattached. Top job and cheaper than a new decat.



Right now my bike is running a lot better but it still feels weaker than it ought to, it stalls at lights much less, and it doesn't sound like the engine will shake itself apart. I'm close to having it nice and smooth but fueling is still really inconsistent to the point where I take corners like a sissy because I won't risk having it cut or surge while I'm leaned over.

Next up: cleaning the fuel injector and fuel filter. If my suspicions are correct that should restore some more power and make the fueling more predictable. After that I'll fit a PCV and richen it a little across the range before I have the time and money to get it properly tuned.
 
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