Nemo's Dyno Charts and notes

[Guest captain nemo]

John and some others were curious about my Dyno tune. You can view all the charts and some notes and comments at my website on this thread:

 

My Webpage

 

 

I have noticed something that I would like to ask you guys about. I noticed after this tune that when I am riding the bike at around it's top torque areas at 3500 and 6000 grand or so that the sound changes to a metallic hammering quality - I call it the 'jackhammer' sound and feel. It is not only my bike, but I also noticed this same sound and feel with Louis' highly tuned Rosa Mandello with his high compression pistons. Anyone else experience this?

[al_roethlisberger]

Hrmmm, hard to say without being there, but it's not detonating/pinging is it? Your description sounds a lot like it. High comp piston mods, and too lean a fuel mixture are scenarios that can exacerbate the already detonation prone Guzzi combustion chamber. Typically a V11 is prone to detonation under hot ambient conditions(80+ degrees) and high RPM accelerations or load.... and it does sound like a jackhammer, because you are indeed "jackhammering" the piston

 

If it is indeed detonation, and is pinging consistently, versus just rarely on a really hot day under hard acclerations(which isn't desireable either, but "normal" for these bikes), you need to have that checked into post-haste, as you'll eat your plugs, and perhaps pistons and valves. You may just have too lean a map, and developing some "hot spots" in the combustion chamber since you don't have enough fuel to cool things down.

 

If you aren't sure, I would run it my Moto International and let one of the techs there run it around the block and see what they say. Again, I don't want to inspire terror, but it's really hard to tell without first-hand listening

 

al

[Guest captain nemo]

Al,

 

Well here is what I know: I have my fuel/air mixture chart so it is easy to see what is happening there. It looks pretty flat and healthy. Also, the bike does this on every stroke right in those bands where it feels the most powerful. I can't believe the tuner guy would not detect a problem. I also go back to Louis' bike and I have confidence that that guy knew what he was talking about. It also had the 'jackhammer' feel. That is a very impressive Guzz. I'd love to see his Dyno.

 

I'm not saying you are wrong, and I appreciate the warning. If the bike was indeed detonating at those rpms, you'd think that the chart would show power loss - but it is in these precise areas where it is the strongest.

 

I have my recall work done next week. I'm sure the guys will take it out for a run and tell me if they think there is a problem. I would love to ride a lot of V11s to really get a feel for these bikes.

[al_roethlisberger]

No worries, I'd just check into it, and it sounds like you are doing so next week

 

 

Again, it's hard to tell much from another's verbal description, so it's just guess-work on my part

 

Let us know what they say though!

 

al

[TX REDNECK (R.I.P.)]

Cap'n I gotta agree with Al, it's detonation. At any rate I would take it easy & not dog it until somebody can look at it

 

Tell me how do you like that sailor term " Thar she blows "