Ducati Monster Forum

I've got my little 695 pretty-much sorted around town using a fatduc.  At the superbike school on Monday, I noticed (I couldn't miss it, as it was pretty loud) my bike enthusiastically backfiring occasionally.  It mostly happened just before turn 2, where I was going from insanely stupid revs to much lower ones.

ISTR that there's some sort of transition between closed loop (where the fatduc helps) and open loop (where the fatduc does nothing, because the bike ignores the O2 sensor).

Since Monday, my bike has been running... differently.  It idles a couple of hundred RPM lower, and feels perhaps a little sluggish.  I dunno whether that is just me perceiving things differently, given that I don't generally ride to work at 7000 RPM, or whether my day at the track had some actual effect.  But if it's the latter, the effect should be positive, right?  All that WOT on the rev limiter down the straight should have removed a lot of carbon deposits.

I pulled the plugs this morning to see if they were fouled, but they were really good.

I'm wondering if my ECU has remapped itself based on the flogging it received on Monday, perhaps as a result of the backfiring and stuff.  I'm pondering removing the battery for a while to get it to reset its map.

Anyway, if anyone has any words of wisdom, I'd appreciate them.  It's probably all in my head.

Hi Suzy, backfiring is generally a sign it's running lean, the ecu can't remap itself..  it may feel a bit sluggish due to having it at WOT on the track compared to riding on the road with all those cagers maybe?

That's a weird one indeed.
Your ECU wouldn't have "remapped" itself because it hasn't got the capability to do it on it's own.

With the Fatduc, it may need a slight tweek again. I had one on my S2R and I had to tweek it a couple of times over a 6 - 9 month period to get it sweet again. (make it run richer)

Hooking the bike up to a VDST can also tell you what's going on with the ECU.

good luck with it suzy

You didnt fill up with Shell halfway thru superbike school did ya? My bike pops and splutters whenever I do.

Aaah!  I filled up there in the morning, and then on the way home.

Before I do anything drastic, I might wait until I've put a tankful of the usual fuel I run through.

good point too..  shell not good...

Homework assignment:

http://www.bikeboy.org/open_closed_loop_efi.html (http://www.bikeboy.org/open_closed_loop_efi.html)

 :)

Oh, I'm miles, miles worse than that.

http://www.microsquirt.info/ (http://www.microsquirt.info/)

Actually, I was thinking my time at the track had affected this:


But then I have no idea, as the Marelli ECU is a completely closed black box to me.

Mine is still back firing after the exhaust leak being sealed. Its shooting some large flames and pops on decel.

I think this sort of thing is pretty common on newer monsters - they set them lean to pass euro emissions standards.  Fitting the fatduc helped for mine in the closed loop part of the rev range, but it's still lean open loop i think.

The older monsters were lean too, it's just a bit easier to deal with, at least the trim can be adjusted.

If you guys have a problem with the local Shell fuel, that could well be it.
Shell is good here, but I don't fill up in Australia.  :P

Are flames out the exhaust normal though? I put in a mid pipe recently and its been tuned

From your avatar it looks like an S4R?
What year and what other mods to the engine??

Flames out the exhaust aren't 'normal' as far as I'm concerned.

Did it just recently start doing this?

suzyj, how high were you revving it?

I can't say exactly, as I was doing >150 km/h and slowing for a really tight turn (after burning down the straight), so wasn't really paying attention to instruments, but I'd guess 7.5 or 8K.

Yes its a 2004 S4R, it started doing it when i put the mid pipe in and got a tune. Header gaskets were replaced and silastic around all fitment points so no exhaust leak.

Is that a termi system?  When you say mid pipe you mean you got rid of the cow udder (ie catastrophic convertor).I have a full termi system with no udder, straight through to the cans, and no flames!  Last time I saw flames come out of a Ducati was my old 650 Pantah.  It was running a 2 into 1 Verlicchi system - loud and shot impressive flames!  [clap]

Yep, termi system, not full. I got rid of the cat and put the mid pipe in.
Im not sure if its me but feels like it might of lost a bit (power), but i have been riding like a hoon lately (just for testing purposes ofcourse :) )

ah ok - to me it sounds like the tune isnt right - when I had the Pantah it used to do the same.  I took it to a friend who balanced the carbies and it never did it again (little bummed at that!).  Cant remember if it is running too lean or rich (explain loss of power too) the fuel that isnt burnt correctly gets re-ignited in the hot exhaust - I am not positive and I am sure one of the sages on here will provide more appropriate and accurate advice.

could be worse - or maybe spectacular!!

R1_flames_Thanks_to_RgTeam_2.avi (http://www.youtube.com/watch?v=jDt_uKhaWEQ#normal)

Suzy, my 695 backfired and surged chronically when I bought it new. Since putting on the Termis, ECU and Air box, I have not had any probs at all. And I think it goes better. It may be the expensive option but it is awesome.  ;D

Monster + Termis = LOVE !!!!!!! [drool]

+1 AH-MEN!  [laugh]

i don't know what how the closed loop system actually works in terms of inplications when open loop, but the s2r1000 certainly ran differently with the sensor connected or not at wot.  so there is still some wot switching with regard to the lambda sensor, altho i don't think it's actually controlling the mixture.

the point at which is switches from open to closed loop on overrun could be the point at which is was backfiring too.  not sure of the mechanics of it.

i don't believe that unhooking the battery for a certain period will do anything to the adaptions on the marelli ecu.  i have seen a "reset adaptions" option on some of the models via the diagnostic tools, but it doesn't seem to be consistant across all models.  i have had ecu out of bikes for certain periods of time where things seem to have changed, but nothing i'd put any sort of confidence in.

it also may be related to what the fatduc actually does in terms of the input the ecu reads, how it's interpreted and the logic of that thru the software.

the location of the lambda sensor could also be an issue - it's on the front header?  as the rear is unsampled any variation between the two could lead to something like this.

i'm not sure what the make up of the newer shell 98 and 100 octane fuels are (i haven't seen the 100 locally for a while), but i mapped one of my bikes on the optimax when it first came out and when running on other brands of 98 the bike ran lean, especially at low throttle openings. i think i added about 20% to the just off closed throttle lines to get it back to where it was, and around 5% at high throttle openings.  so if they're still the same the extra richness at lower throttle openings could have an impact.  maybe ring shell and ask them, altho do it with an enquiring attitude, not a "your fuel is crap" attitude.

Turns out it was all my imagination.  My bike ran beautifully today, never missed a beat.

I'd say it was probably the fuel then.  I sometimes think mine is losing power and feels sluggish then I fill the tank with something else and all is okay again. I do have to use some questionable fuel at times, living and riding out in the sticks as I do.

I usually put premium in mine but filled up with 95 instead today to see if the flames and back firing would settle down.......... didnt really

do you need the lambda sensor?  My S2R1000 has no cat - where the mid pipes are there is a balancing pipe with a spot where I guess a lambda sensor would be bolted in.  I have a DP ECU, open air box, and open pipes all the way through to the termis.  Never had the problems described here.  Always run BP Premium unleaded as I found the others left the bike a little off key - if that makes sense.

I am happy to put up some photos of my mid/balance pipe where the sensor is meant to be if anyone is interested.

 [thumbsup]