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Discussion Starter #1
Anyone experienced this? When starting the bike cold (i.e. has been in the shed at least overnight) the bike starts, hesitates slightly and then revs to anywhere between 4,000 to 5,000 rpm before fairly quickly dropping back to a more correct 1,500-ish rpm. Note that when I say 'cold' I don't mean cold weather. I live in Brisbane, Australia and it's summer so daytime temps are 30 degrees centigrade (86 F) or more pretty much every day. Once the bike has been ridden and warmed up it does not exhibit this behaviour when re-started - not until the next cold start anyway. A bit of background on something I believe is associated - due to the appearance of a yellow warning light on the dash, back in early November a new ECU was fitted by the Dealer. This was after they had fitted a replacement Lambda Sensor to one of the header pipes to correct whatever was causing the warning light and the light remained on. Post ECU all good as far as running and performance but every single cold start since then this over-revving has happened. This week it went back to the Dealer to correct the problem. Due to them having to test their work only with a cold engine they had the bike for 4 and a half days. After my second call I was advised the "bike was ready to be collected". Note the language used - they did not say it was actually fixed. The Workshop Manager casually told me before I rode away that the "issue" might occur again. I objected and was told that "they all do that" (rev up to 4,000 rpm). I call BS to that. My bike did not experience this problem before the ECU was replaced. I think the Dealer has mistaken me for a fool and hopes I will just cop this and put up with it. So.……...my request to you, fellow Dukers, is do your bikes rev to 4 or 5 thousand when you start with a cold motor? Do you think my Dealer is ethically challenged - I sure do! Cheers,
 

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What would be the temp at "cold".? And is the bike kept at ambient or warmer/colder?. I have had mine peak a bit once or twice - 2500 ish though.

I have had other bikes do this and it's always been because the filterbox Air temp and engine coolant temp have been out of sync somehow.
 

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The way my bike starts and warms up is also inconsistent, but has no affect on the bike's on road performance. Some days it starts, then ranges up to around 3000 rpm a few times before settling down. Other days it starts and just holds 2000 rpm before settling down around 1500rpm. Been like this since the first service. From new it would just hold around 2200 rpm for about 20 seconds, then reduce. I am not sure you have a problem, except for the fact that 5000 rpm does seem high on a cold start.
 

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Discussion Starter #4
What would be the temp at "cold".? And is the bike kept at ambient or warmer/colder?. I have had mine peak a bit once or twice - 2500 ish though.

I have had other bikes do this and it's always been because the filterbox Air temp and engine coolant temp have been out of sync somehow.
I keep the bike in a colourbond (metal) shed separate from the house. The bike would be perhaps slightly cooler than the outside temp in the shade. Say, 20 degrees C in the middle of the night. Really, there wouldn't be much difference. I can't help but think that the point of negative deviation from the previously normal operation of the motor was when the new ECU was fitted. Part of the problem here is that no paperwork is provided on warranty work, plus the workshop manager doesn't offer much if any information as to what work was done. Maybe he's always like that or maybe he just thinks I'm a pest. I don't pester them at all - for $15,000 I think I should be told what and why. Cripes, $20,000 will buy you a new Hyundai i30 so it's not like it was a cheap Chinese import.
 

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The way my bike starts and warms up is also inconsistent, but has no affect on the bike's on road performance. Some days it starts, then ranges up to around 3000 rpm a few times before settling down. Other days it starts and just holds 2000 rpm before settling down around 1500rpm. Been like this since the first service. From new it would just hold around 2200 rpm for about 20 seconds, then reduce. I am not sure you have a problem, except for the fact that 5000 rpm does seem high on a cold start.
Your situation sounds OK to me and I wouldn't be concerned if my bike did the same thing. Revving approx half way to red line just doesn't seem within the normal range to me. I also got aggravated when 4 and a half days went by with no contact from the dealer and when I chased them up (politely) for the second time suddenly "your bike is ready to be picked up". No mention that they hadn't fixed it, no recognition that it didn't perform this way for the first 5,000 klm of its life prior to the new ECU and only the weasel words that "they all do this" once he covered his arse by suggesting it "might" do it again - which it did, immediately and at 4,500 rpm.
 

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There is always the "make or break" solution. Write to consumer protection and copy KTM (I mean the factory and official importer). The dealer WILL hate you forever. But sometimes it's what it takes.
 

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Happened to me 2 times now. But it was below 10°C outside and after a week of not riding due to low temps etc. I remember my duke 125 would do thats on a cold night after I finish work at midnight. The temps just above 0°C and it would start normally and after few sec would sit at 5000 or 6000 rpm and would go back to normal idle after 15sec.

Ive done 13000 miles so far on my 790. What about u ?
 

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mine does this, has always done it.
it needs to be farily cold though, around 10-15C then the revs will hunt for about 50 seconds.
sometimes even stalling.

I restart or blip the throttle and it's fine.

hopefully unrelated my bike is in for new valves, new piston head, new seals and uneven wear on a cam.

i'll let you know if it still does it when i get it back.
 

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... no paperwork is provided on warranty work...
Wait, what?

you should get a reciept of parts ordered. Can you take it to another dealer? Also the work should be logged onto KTMnet so you should be able to go to another dealer and ask them. You can't ring up KTM frustratingly and the web form just gets forwarded to your local dealer.

My dealer in Sydney knew what the original dealer in perth had done.
 

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Yeah mine does this on cold start up but quickly drops back to idle rpm. I'm in syd and the temp is around 22 degrees in the morning.
 

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Discussion Starter #11
Happened to me 2 times now. But it was below 10°C outside and after a week of not riding due to low temps etc. I remember my duke 125 would do thats on a cold night after I finish work at midnight. The temps just above 0°C and it would start normally and after few sec would sit at 5000 or 6000 rpm and would go back to normal idle after 15sec.

Ive done 13000 miles so far on my 790. What about u ?
It's hardly ever what would be called 'cold' here in Brisbane and everyone who has experienced this issue seems to have come from areas that are genuinely cold. I guess the main query is "does this damage my engine?" Even if it doesn't it just worries me that it didn't do this before the ECU replacement. As I said to the Workshop Manager "I've had 15 bikes over the years and none of them have done this." How come an old Enfield with a carby will run OK from sea level to 4,000 metres and a you-beaut computer-controlled modern bike has a fit after a brain transplant? My bike has done approx 6,500 klms since new. The Dealer, at my request, has said he will email the Australian Importer and see if this issue has been reported previously. If so, there may be a fix? Again, it worries me that they didn't already do this, despite having the bike for the best part of a week without fixing it. Thanks for your response :)
 

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Discussion Starter #12
Boy, I'm upset about my Bike. You must be less than happy with yours? How many kilometres on yours? Do you do track days or just 'normal' riding?
 

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There is always the "make or break" solution. Write to consumer protection and copy KTM (I mean the factory and official importer). The dealer WILL hate you forever. But sometimes it's what it takes.
It may come to this yet. At this late stage of my life I have decided I am not going to allow anyone to brush me off like this. If I let this matter slide I would hate myself. Them hating me doesn't phase me one little bit. I have 15,000 reasons for expecting them to do their jobs properly. I am/was seriously considering buying a 1290 Super Duke R (God help me) but it won't be from them the way things are going so far.
 

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Discussion Starter #14
Wait, what?

you should get a reciept of parts ordered. Can you take it to another dealer? Also the work should be logged onto KTMnet so you should be able to go to another dealer and ask them. You can't ring up KTM frustratingly and the web form just gets forwarded to your local dealer.

My dealer in Sydney knew what the original dealer in perth had done.
I can get the direct phone number for the Importers "Complaints" guy from another source so if push comes to shove I expect I'll find this stuff out if the local Dealer tries to brush me off any more than they already have. They may be nice guys but, as it happens, I'm not. Not by a long shot.
 

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Hi Ken, l’m on the GC and my bike has done this twice in the first 5000 km including once when it was 36C so it’s not just a cold ambient temp issue though l guess that could exacerbate things. Good luck with this
 

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The word COLD needs to be seen from the ECU's view of life. COLD is probably under 50-60°C.

On my Big Triumph I run all sorts of data loggers and noticed a marked change in cold/warm starts when ambient hovered in the 20-25°C zone. Modifying the ECU map very marginally cured it for where I live (almost 1KM vertically up) - but changed things for the worse where my mum lives near the sea. Later mods using a PCV/AUTOTUNE based on MAP fixed it completely.

When you "COLD" start the ECU takes some factors as given - usually this involves opening the throttle butterflies by a small margin - 5-10% and a fuel quantity based on the various sensors. This based on tested across the board factors that result in a given AFR and eagerness to fire and run stably.

In the case of KTM and the one push start thing - the design is probably to fire fast if not immobilized.

Sensors have tolerances. So do injectors and stepper motors. So it can mean that either a bike simply does not start OR is over eager and has to be trimmed back. Which would you prefer? - So my guess is they use fire and trim back as the option.

Incidentally my Wife's Citroen Diesel does it occasionally too. It's far from new and it's a mismatch of the water temp sensors either side of the thermostat.

Sensors in play? - Air temp inside filter box certainly. Maybe block/water/TB temp. Air pressure (this affects O2 quantity). Those spring to mind.
And it's not the ABSOLUTE value - it's how they all relate.

If it really worries you - write to KTM HQ (not a dealer) asking for confirmation that this is normal and non threatening. But document it clearly.
 

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Discussion Starter #18
The word COLD needs to be seen from the ECU's view of life. COLD is probably under 50-60°C.

On my Big Triumph I run all sorts of data loggers and noticed a marked change in cold/warm starts when ambient hovered in the 20-25°C zone. Modifying the ECU map very marginally cured it for where I live (almost 1KM vertically up) - but changed things for the worse where my mum lives near the sea. Later mods using a PCV/AUTOTUNE based on MAP fixed it completely.

When you "COLD" start the ECU takes some factors as given - usually this involves opening the throttle butterflies by a small margin - 5-10% and a fuel quantity based on the various sensors. This based on tested across the board factors that result in a given AFR and eagerness to fire and run stably.

In the case of KTM and the one push start thing - the design is probably to fire fast if not immobilized.

Sensors have tolerances. So do injectors and stepper motors. So it can mean that either a bike simply does not start OR is over eager and has to be trimmed back. Which would you prefer? - So my guess is they use fire and trim back as the option.

Incidentally my Wife's Citroen Diesel does it occasionally too. It's far from new and it's a mismatch of the water temp sensors either side of the thermostat.

Sensors in play? - Air temp inside filter box certainly. Maybe block/water/TB temp. Air pressure (this affects O2 quantity). Those spring to mind.
And it's not the ABSOLUTE value - it's how they all relate.

If it really worries you - write to KTM HQ (not a dealer) asking for confirmation that this is normal and non threatening. But document it clearly.
Thank you for your comments. I'm still waiting on a response from the Dealer but am unlikely to hear from them until after the Xmas break. If no timely response I will definitely write to KTM HQ as suggested. Again though - the issue did not occur until after the Dealer swapped out one of the Lambda Sensors and then subsequently replaced the ECU. Curious although not necessarily relevant I know. Cheers all for Xmas and 2020!
 

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I got my 2019 790 at the end of September and it's experienced this issue the whole time I've owned it. The over-reving hits in the first block or two or riding for me (I've even stalled it out a few times because I can't tell how much there I'm giving it when the refs go on their own). When I took the bike in for the 600 mile service, I brought it up, and the dealership told me it was just trying to find it's sweet spot, and it wasn't throwing any diagnostic codes.
It was a pretty regular occurrence for me. For the past week and a half, I've been starting it up and letting the bike run while I put in my ear plugs and put on my helmet and gloves. That's maybe a minute, tops. Haven't had a problem with it rev hunting when I do that.
Out of curiosity, do you know if the old ECU had the same version of software running as the new one that was installed?
 

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Discussion Starter #20
Hi Glenntropy (great name by the way). The software version (1.02) hasn't changed.

For what it's worth, I always put on my helmet & fit earplugs after I've started the bike. Old habits die hard. I prefer to not ride off until the temperature gauge hits 2 bars as a minimum.

Incidentally, the last two times I have started the bike it hasn't done the over revving thing. It does still run rough initially. Too early to tell if the issue has fixed itself. I'm not optimistic by nature so we'll see what happens.

Either way the Dealership Workshop has not covered itself in glory. Neither has yours I'd say - "just trying to find its sweet spot" is a bullshit comment. I bet no Japanese or German bikes have to hunt around up & down the rev range to decide how they are going to run.........

Ciao,
 
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