Knock,knock, Who's there ?

[Huzo]

Ok, an issue that has almost always been with me on my '07 Norge. There are a few guys on this forum from which I would really like to hear from. My bike has a tendency to "ping" or "knock" under certain conditions of temperature and throttle settings. The most provocative combination is, high temperature (30 deg c) and above, RPM at or below 3,500, and high throttle setting ( no not flat to the stops). The best example is, if you imagine you're in the mountains on a hot day at high altitude and you've descended down a long grade, gone around a bend and cranked back up the hill in the opposite direction. The only reason I nominated that example is it was one of the memorable ones where it occurred. You can ride around it by keeping revs up and rolling off the throttle a bit, but if you are cruel enough to labour the engine you'll cop it. I recently took it to a known and widely trusted specialist who almost completely removed the issue by "tweaking" the map and richening the mixture slightly at sub 3,000 rev, high throttle setting regime and it's fabulous but now uses about 5.6 l/100k whereas used to be about 5.2 l/100k. I'd like to hear anything Pete Roper or similar, has to say on this

[Huzo]

Yeah it's hard to tell from here who are unwashed. For sure Pete is one of the few that I referred to ( actually he is the one), but I'm sure there are others who have something to contribute. Having said that I'm sure Pete would have something worthwhile to say on the topic. I'm not clueless in regards to the consequences of allowing detonation to occur in engines. In aircraft with constant speed propellers you can use a variety or Manifold Pressure/ RPM combinations to achieve 75% power for cruise, but over boosting can cause detonation issues in some conditions which won't allow you to lean the mixture. Now that's ok when you can refer to a table for data, but on the bike it was an issue for a while. These days not so much but then again I don't provoke it.

[Kev m]

Sounds like my 06 Breva 1100 which did it from the start and not the selling dealer (Speakers), nor Eraldo Feracci (who I believe didn't look at mapping) could make go away.

Pete actually took a quick look at it, but he could only say the map was factory and wondered if the ECM was faulty.

Anyway the problem persisted until I had Todd at Guzzitech reflash the ECM. Then it never repeated.

I suspect that if GuzziDiag had the MAP reader ready neck then, then Pete or I could have easily fixed it for free.

[PJPR01]

Bit of a crossover from the other thread, but are you perchance running low octane gas, or an ethanol mix? 

I've never had a ping on my Norge, but I do notice it runs noticeably smoother on 93 vs. 87, and sometimes in places I've been forced to put an ethanol blend for 1 tank, it runs noticeably worse, like it's laboring a bit and I can't wring out the roughness/vibes...

[Huzo]

Yeah it was the other thread that prompted me to post this one. I always try to find the highest octane fuel I can and here in Oz that's 98. I know that 100/130 avgas has a release note for each batch of fuel that guarantees the octane rating, but there's no such thing for auto pump gas here. Just to put it in perspective, I now don't have the problem given the treatment to the map and the way I ride

[Rough Edge racing]

 Hot temperature, lower rpm's and load is fertile ground for pre ignition and or detonation...This is especially true of older design slow burn two valve combustion chambers....Easiest thing to do is keep the engine above 3500 rpm...............T he octane rating on the pump doesn't mean much without considering the MON octane rating. The MON rating is done under more severe conditions that are more realistic when it comes to bike engines. In the USA the pump octane rating is the average of MON and RON. In Australia, what is the octane rating based on ?

[chuck peterson]

Drop two gears and call me in the morning?....I dont know

[Huzo]

I don't know the answer to your last question rough Edge, but thanks for the info, good to know it's symptomatic of the design and not a fault with mine alone, as mentioned it's not now a problem, but a few bits of valuable advice. Thanks.

[LowRyter]

too lean, too much timing, too much compression. 

remap and run higher octane?

[Huzo]

Always ran highest octain available, map has been re worked and as mentioned issue has gon but a BIT more thirsty, but totally acceptable

[CalVin2007]

  I have been modifying the map in my CalVintage (1100 2V engine with Breva internals)  for a while now. Pinging with the factory map was quite bad and one major reason for me to modify. I have found that reducing timing advance in the affected rpm ranges as well as slightly richening the mixture (if required!) has made a vast improvement in eliminating detonation (ping) and -believe it or not- improving fuel consumption. The engine runs smoother as well, and now runs like it should. The stock timing map was absolutely horrid...I was shocked when I first saw it. I highly recommend starting there to anyone looking to deal with a detonation/ping problem. Fueling adjustments can come after, but in careful increments and with testing.
   THANK YOU to all the GUZZIDIAG developers/providers/experts!

   Terry

[Huzo]

Ok Cal Vin, again interesting.

[Groover]

This may seem simple considering what you've tried, but try some colder grade plugs. Also, keep track of which gas station's fuel is causing the most pinging.

[ITSec]

The octane rating on the pump doesn't mean much without considering the MON octane rating. The MON rating is done under more severe conditions that are more realistic when it comes to bike engines. In the USA the pump octane rating is the average of MON and RON. In Australia, what is the octane rating based on ?

Australia and NZ use only the RON rating for labeling. The MON rating of their fuel is not usually published, though there's no reason to believe that it is much different from NA fuel. So AUS/NZ 95 fuel is likely to be much the same as US/CDN 91.

[Wayne Orwig]

If one of the twin plugs is not firing, do you just lose power, or can that aggravate detonation?

[Kev m]

I guess I should add that when Todd reflashed my ECM I not only didn't take a hit in mpg but increased mpg at certain parts of the powerband (mostly at heavy throttle).

[CalVin2007]

If one of the twin plugs is not firing, do you just lose power, or can that aggravate detonation?

   Wayne-

    My CalVin loses power with the inner plugs not firing. No ping, likely due to the later peak cylinder pressure effected by the timing map for dual plugs and only one firing. I intentionally grounded the inner plugs as an experiment while playing with mapping...may do it again sometime with a serious effort to remap fuel and ignition to suit.

  Terry

[oldbike54]

   Wayne-

    My CalVin loses power with the inner plugs not firing. No ping, likely due to the later peak cylinder pressure effected by the timing map for dual plugs and only one firing. I intentionally grounded the inner plugs as an experiment while playing with mapping...may do it again sometime with a serious effort to remap fuel and ignition to suit.

  Terry

 Terry , you mentioned peak cylinder pressure , or more accurately moment of peak cylinder pressure . With all of the discussion re octane lately no one else has mentioned the relationship between  that and octane    , will let you explain it .

  Dusty