Detonation (spark knock, pinging, etc) when hot

[jkristjan]

I think I got detonation on my V9 as the weather changed to warm a few days ago. When sitting in stop and go traffic and the engine gets real hot, an ugly metallic noise that sounds like detonation results under heavy load. In EU, we have 95 and 98 octane fuels, which are roughly equal to your US 90 and 93 (this is the ROI vs MOI vs AKI index, look it up if confused). Anyway, I was using 95 and switched to 98 now, will be observing it on the hot days to come. What are your thoughts and experiences, maybe others noticed same thing on the specific 853cc V9 engine?

 

[john zibell]

If you hear that sound again, drop a gear or 2. That will reduce the combustion pressure and should eliminate the detonation.

 

[jkristjan]

If you hear that sound again, drop a gear or 2. That will reduce the combustion pressure and should eliminate the detonation.

Well it is not doing it steadily, only for a moment in the middle of acceleration so even if I don't change gear, it just crosses over to higher RPMs in a second and stops. Anyway, avoiding using the torque or a low-revving V-twin cannot be the real solution, for now I am hoping that the solution for hot engine situations is higher octane fuel. If it's not, I have to pursue a warranty case. I don't live in a hot climate actually and my "hot" only means 26C/79F and a nice breeze. It's an Italian bike and dubbed "urban cruiser" so it has to be usable in Milan/Rome/Naples traffic in a 100F day, otherwise it is malfunctioning

 

[GTM®]

I have stated for a decade and a half about "air-cooled" engines being largely fuel cooled. You are dealing with stingy Euro-4 emission regulations which run these bikes very lean and hot. It is why I offer a solution on the online Store to help resolve these issues. Most dealers will not be of any help with this as they are tied to Piaggio's online system for maps.

 

[GuzziMoto]

I run premium in all of my Guzzi's, that would be of the 91 - 93 octane AKI (RON + MON / 2). I find lower octanes knock, especially when hot.
I do have Todds full kit on my Griso, and a Power Commander on the V11 Sport. Todds mods to fueling do help it run better, but they did not stop it from needing higher octane to avoid knocking.
V7's and V9's are not low reving motors, though. They are twins, but not all twins are torque motors.

 

[bkiser]

I run nothing buy US 93 octane in mine and have had no pinging issues even at 90F degrees. But, definitely don't lug the motor at those temps- let it rev a little. Overall, this bike seems to run much cooler overall than my previous 2004 Bonneville.

 

[jkristjan]

Finally found a video of someone riding the V7 III, capturing the exact same momentary metallic noise my V9 makes. Have a looksie and tell me what you make of it:

 

[Vagrant]

look at the gas tank. it appears that it is shaking so hard it's hitting the top of the frame.
my 2015 V7 has 12000 miles of 90% 85-87 octane and has never knocked. plenty of that was in 90+ degree heat in Az.

 

[TweeZ4]

Finally found a video of someone riding the V7 III, capturing the exact same momentary metallic noise my V9 makes.

Have you already tryied high octane (EU98 or 100) fuel with your Bobber? How was it?

 

[TweeZ4]

look at the gas tank. it appears that it is shaking so hard it's hitting the top of the frame.
my 2015 V7 has 12000 miles of 90% 85-87 octane and has never knocked. plenty of that was in 90+ degree heat in Az.

I guess you have a pre-EURO4 bike, which burns more reach fuell/air mix than EURO4 v7III and V9.

 

[jkristjan]

Have you already tryied high octane (EU98 or 100) fuel with your Bobber? How was it?

Yes I did and it seems better, actually haven't had that sound with 98E fuel. But that is not a 100% sure measurement because I can't control the temperatures and traffic jams, it may just be that I have not had as much heat since switching fuels (or that I have not lugged it enough).

look at the gas tank. it appears that it is shaking so hard it's hitting the top of the frame

Nope, it's not that. My V9 which has a very different tank makes exactly the same noise and it is coming from the engine. The older V7s never make it, in that video he is riding a V7 III which has basically the same engine as V9 and now it makes the same clicking too. The most significant change to these engines is the head/valve design and leaner fueling to accommodate EURO4, so there's a clue.

Anyway, coming back to the original question - folks who are experienced in recognizing spark knock, whaddaya think, is that it? Formerly I found only videos demonstrating similar sounds from car engines and such, but now this video is a 100% match with my sound.

 

[GuzziMoto]

I don't know if what you are experiencing is detonation or not. But a simple check is to pull the spark plugs after it has just done what you suspect is detonation / knock and look at them. If you have more than a minor amount of detonation there will be signs of it on the spark plugs. If there are signs of detonation on the spark plugs you need to do something. If there are no signs of a problem on the plugs you probably don't need to worry about it.
But I would run higher octane fuel regardless. I did not know Guzzi even suggested you could run anything but.

 

[Eldo1400]

Holy cow, I get the same exact noise on my V9! Was wondering what it was. Now I'm watching/listening to that YouTube like it's the Zapruder film lol.

Detonation? I don't know. I've so far gotten that noise when the engine is still warming up, and I'm accelerating in the lower midrange. Nothing bogging, nor any hard accel (still in break-in).

My theory of the case has to do with Euro 4. Mainly, that this particular regime of being *almost* at full operating temperature causes emissions problems, and that their may be a programmed-in lean-out condition leading to some detonation -- even under a relatively light load. Such things are not unknown in the arcane world of emissions tuning.

OTOH, it does't really sound like classic detonation. I've had that on my 1400, big booming unmistakable detonation. Here it's a strangely mechanical noise. Back to the Zapruder film.

Our solution is Todd's remap.

 

[timax]

I get the same sound with 98 RON fuel in my V7ii.
Under load usually bellow 3000 rpm and especially 2 up.
Im guessing its pre ignition but surprised i get it even with 98 RON fuel. Plugs show signs of soot rather than running lean.

 

[Dinsdale Piranha]

I don't believe that the sound in that video is detonation/pinging. Pinging has a higher pitched tinkiey metallic sound - like a dozen miniature men in there beating like crazy on your piston crown, with tiny little hammers. Perhaps (only perhaps) a slightly too wide tappet gap, but even that doesn't sound quite right. My manual is outside in my garage (and I'm not going out to get it right now), but iIrc it says to use 95RON or higher for my V7iii.

 

[FinnF4i]

I get the same sound with 98 RON fuel in my V7ii.
Under load usually bellow 3000 rpm and especially 2 up.
Im guessing its pre ignition but surprised i get it even with 98 RON fuel. Plugs show signs of soot rather than running lean.

I just did my first 2up on my bike last night (2017 V7 III Special) and heard an odd noise at lower RPM which I don't recall when solo, or if I did maybe just not to the same extent (as this was very noticible). Was in the evening, air temp was probably around 28 C after a 31C or so Max during the day (I live in Adelaide). So sounds like I experienced what you just explained (low rpm load, with 2up), and I also run 98. Not sure how our fuel compares to others around the globe? I have the ECU flash tool on it's way to me as I type, hopefully I'll have it any day now. I'll upload a revised map from Todd (I have freer flowing mufflers) and see if that make any diff next weekend when I'll probably have a passenger again (but temp will be lower next weekend) .

I did notice however that as the ride progressed, whether or not temps may have been different, or maybe just due to me adjusting the way I was riding as I got used to the extra weight of 2up on this bike, that I was less aware of it. When I first started out was when it was most pronounced.

 

[Kev M]

I get the same sound with 98 RON fuel in my V7ii.
Under load usually bellow 3000 rpm and especially 2 up.

This isn't a Harley BT, < 3000 rpm is too low for much of a load or hard acceleration in most higher gears.

And of course fuel octane matters, but so does ambient temp, humidity, altitude etc.

 

[Vagrant]

This isn't a Harley BT, < 3000 rpm is too low for much of a load or hard acceleration in most higher gears.

And of course fuel octane matters, but so does ambient temp, humidity, altitude etc.

Very correct! the 2017 runs great at 500 less RPM than older models but with 2 up 4000 in third and up is the min. RPM. in second maybe 3500.

 

[Bill Hagan]

I like resurrected threads; they give the perspective of a bit of time to OP problems and early answers. OTOH, the OP hasn't been back -- at least in the sense of logging in -- since June.

Anyway, I deny to Kathi my erosion of hearing -- retired Army guy; big guns use big bullets and make big noise -- so maybe that's why, but I can only rarely recall hearing "pinging" on any of my Guzzis, and that only on my EV. I know the sound; our 4-wheeled vehicles have done it enough along their million-and-more miles.

But I also have, only once -- on my EV more than 15 years ago -- used anything other than premium fuel ... well, at least that what the pumps said, and I have not always been able to be picky and gotten "top tier" fuel from known vendors.

Mebbe the OP and others "over there" just need to use more ethanol in their tanks?

Seriously, I am with DP .... uhm, that won't do; I mean Dinsdale Piranha -- in that the vid, at least, illustrated, was not "pinging" in the usual sense. Given my typically low number of tech arrows in my mechanic's quiver, I don't know what that sound is, but -- unless someone here more familiar with Guzzis doing the ping thing says otherwise, I think there is something else amiss.

Back now to those who know what they are talking about ...

Best,

Bill

 

[Joel Eames]

I experienced this today (riding a V9). Stuck in stop-and-start traffic for 2 hours and when I finally started accelerating I clearly heard the motor pinning. Downshifted and took it easy till I got enough airflow to bring temps down.

I think I got detonation on my V9 as the weather changed to warm a few days ago. When sitting in stop and go traffic and the engine gets real hot, an ugly metallic noise that sounds like detonation results under heavy load. In EU, we have 95 and 98 octane fuels, which are roughly equal to your US 90 and 93 (this is the ROI vs MOI vs AKI index, look it up if confused). Anyway, I was using 95 and switched to 98 now, will be observing it on the hot days to come. What are your thoughts and experiences, maybe others noticed same thing on the specific 853cc V9 engine?