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Discussion Starter #1
Hi all,
I have a monster 1200S with CF termigoni slip-ons and ECU sports map year is 2015.
I have always noticed to varying extents that fueling is on off or "stutter" like, as if fuel is being taken away then given away then given back, surging almost, it happens only when i hold the throttle steady at about 4800 RPM, it's there in all gears but most noticeable in 1st gear. It is not noticeable if you simply accelerate through this rev range but sometimes if I am going slow in traffic it's annoying. It doesn't seem to occur at any other point in the rev range. I remember this being the case pretty much from day one, having this inconsistent or not smooth fueling at this rev range. Of course it is much less noticeable in higher gears but it is there. Due to a myriad of other problems I had with the bike I had the ecu replaced, throttle assemblies and such and this never made any difference. I just wonder if anyone notices this on theirs. I notice the effect is amplified if the bike is really hot, which is why I am posting this I was riding bout a week ago and it was really hot and it was doing this in a really pronounced fashion, heat aside it is consistently there to a lesser degree...Any thoughts appreciated.
thanks,
Des
 

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Near that rpm on my 821 I experience the same phenomenon...Its more than likely the resonant frequency of the intake and exhaust gases canceling each other out ...when the exhaust and intake are open at the same time their corresponding pressure waves disturb one another at a given frequency...in this case around 4k rpm...the dip is easily seen in the engines power curve...I just stopped going below 6k when I hit the fun stuff...also for what it's worth..and regarding the 821 not necessarily the 1200...if your openers are at the low end of spec say .15mm or lower the problem is more pronounced and it will not cruise well at all at anything below or near 4k rpm
 

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Possibly just down to emission requirements.
On a steady throttle these ducs are trying to run as lean as possible.
Mine (base 1200) is bad enough to be annoying! Its definitely running lean - the engine almost feels ‘tight’.
-(I also fitted an Arrow silencer and that won’t have helped either..😫)
I’m fitting a Rapid bike Evo and getting it dynoed to fix this.
Hope it works or i’m Buying another Speed Triple😆
 

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Discussion Starter #4
Buhgaboo,
Thanks for the info, I'm not that technical so I wouldn't have thought about this but makes sense. Just couple questions when you say it can clearly be seen in the power curve is this available for 821 and or 1200 from Ducati as documentation or did you dyno your bike to see this? Also not sure when you’re talking about openers what are they and how wold they exacerbate the situation? Is this something to do with the exhaust if so the headers on my bike are factory I only put on slip on termis and the ecu update.
thanks,
Dest
 

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Discussion Starter #5
Towbar,
when you say it's bad enough to be annoying do you get the effect around 4800 RPM? or is it just more a constant thing?
thanks,
Dest
 

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Buhgaboo,

Thanks for the info, I'm not that technical so I wouldn't have thought about this but makes sense. Just couple questions when you say it can clearly be seen in the power curve is this available for 821 and or 1200 from Ducati as documentation or did you dyno your bike to see this? Also not sure when you’re talking about openers what are they and how wold they exacerbate the situation? Is this something to do with the exhaust if so the headers on my bike are factory I only put on slip on termis and the ecu update.

thanks,

Dest
The power curve I got from a Google search for "monster 821 power curve"...never been on a dyno...but you can see on the torque profile that it gradually declines until ramping up around the 5-6k rpm mark...the openers relate to the valve shims...it's the opening that is more critical to performance than the closing...as the clearance grows or shrinks it is essentially affecting the engine timing and valve overlap...thus effecting laminar flow... creating turbulence... and disturbing the exhaust gas scavenging effect etc...the engine really likes to be ridden at a specific aggression level...your either just cruising along or setting a lap time lol...the more maniacal you become the happier my monster gets
 

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Hi Des,

It does sound like it's running lean at that throttle setting. Just changing pipes and putting in a sports mapped ECU will most likely give you a map for 'sport' conditions, ie. more fuel at high revs with not a lot of fine tuning at lower or steady throttle.

Yes, it is a Ducati, but any fuel injected modern engine should run smooth from 2k up. You should consider getting it on a dyno with O2 or fuel ratio sensor. The modern systems are a lot more complex than before, a custom map may help.

I live in Perth, not sure where you are in Aus. If on the east coast, there is a guy named Brad Black who is somewhat an expert on tuning Ducati's. Also a forum member for many years. I would contact Brad and if not able to get to him he should be able to give advice. he is in Victoria.
http://www.bikeboy.org/index.html

Hope this helps.
 

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Hi,
It’s just low revs 3-4K, gears 3,4,5 &6 that I’ve noticed, trying to maintain a constant cruising throttle up the freeway...any more revs and I’d lose my license😫 if I accelerate it goes just like you’d expect a 1200 bike to.
Getting dynoed on Friday at Pro-twin our local Ducati specialist. Justin admits that the fuelling on these bikes leaves a lot to be desired. I am fussy about my fuelling...
I’m also interested to see how good these new ‘rapid bike’ tuning systems are. I’ve always used dynoed or Bazzaz in the past.
👌
 

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@dest_77
At that RPM, I suspect it's your exhaust valve closing.
Try disconnecting the cable. It will throw a CEL but see if that doesn't isolate the issue.
 

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Discussion Starter #10 (Edited)
@DarR I haven't noticed the exhaust valve move at all since I put the termigoni slipons on and had the ecu updated to the sports map. My understanding is that the updated ecu map disables the valve. Just to make sure we are talking about the same thing though here, i am talking about the flap/valve on the exhaust pipe just before where the mufflers join to the pipe. This valve pre-ecu sports map update used to open and close, it was disabled after the dealer updated the ecu and added the slip ons.
thanks,
Dest
 

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Discussion Starter #11
@ronski,
Thanks for the info, as luck would have it I actually do live in Victoria! I looked the guy up and he looks like he could def help. At this stage though the bike is still under warranty, so i guess what I was trying to get an idea of is whether this sort of thing is just part of the "ducati fuelling" so to speak, and not necessarily a fault as such, or something that might be covered under warranty. So at this stage I don't want to get a custom map, it's not a showstopper problem just a bit annoying I just wanted to see if anybody else has experienced something similar to this before I handed my bike over to the dealer for them to look at it.. which from past experience can take a while and if it just is something that you gotta deal with then there's no point...
cheers,
Dest.
 

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Discussion Starter #12
@Towbar thanks for the info, sounds the same as mine. Be keen to hear how you go with the dyno and tuning if you have time to post back. In particular whether they make any suggestions to eliminate or alleviate the problem.
thanks,
Dest
 

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Discussion Starter #13
Hi Des,

It does sound like it's running lean at that throttle setting. Just changing pipes and putting in a sports mapped ECU will most likely give you a map for 'sport' conditions, ie. more fuel at high revs with not a lot of fine tuning at lower or steady throttle.

Yes, it is a Ducati, but any fuel injected modern engine should run smooth from 2k up. You should consider getting it on a dyno with O2 or fuel ratio sensor. The modern systems are a lot more complex than before, a custom map may help.

I live in Perth, not sure where you are in Aus. If on the east coast, there is a guy named Brad Black who is somewhat an expert on tuning Ducati's. Also a forum member for many years. I would contact Brad and if not able to get to him he should be able to give advice. he is in Victoria.
http://www.bikeboy.org/index.html

Hope this helps.
The power curve I got from a Google search for "monster 821 power curve"...never been on a dyno...but you can see on the torque profile that it gradually declines until ramping up around the 5-6k rpm mark...the openers relate to the valve shims...it's the opening that is more critical to performance than the closing...as the clearance grows or shrinks it is essentially affecting the engine timing and valve overlap...thus effecting laminar flow... creating turbulence... and disturbing the exhaust gas scavenging effect etc...the engine really likes to be ridden at a specific aggression level...your either just cruising along or setting a lap time lol...the more maniacal you become the happier my monster gets
Thanks for the explanations @Buhgaboo re the openers.. makes sense.
cheers,
dest
 

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@dest_77
That was my best guess. If that's not it then the problem is above my pay grade. You're best to have a pro tuner look at it.
 
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