Gyrobob wrote on 02/09/13 at 11:07:01:Max cylinder temp happens with a perfect stoichiometric ratio, approx 14.7:1. If you are rich (maybe 12:1) or lean (maybe 16:1) of that point, the cylinder temp goes down.
The danger from lean mixtures is from detonation, not heat. Lean temps can burn unevenly, or even too rapidly which can lead to detonation, even though the temps are not as high as with a 14.7:1 ratio.
...Im thinking Bob meant to say Lean Mixtures can burn unevenly blahdeblaaahblaah & so on,,....
Anyway, if the fuel gets hot enough to catch on fire before the spark plug fires, thats detonation. If its doing that while the piston is still headed up, then thats pounding the POO outta bearings at the very least. What other damage mite it cause? I Dunno,, Thats just MY imagination at work there.
What does it matter that flame front propagation is uneven? I can see it affecting power, but I dont see it hurting equipment. Bob may well correct me on that.
I hope others will explain further the problems detonation can cause.
I understand. Like a diesel engine fires with out a spark plug due to pressure. So on an extremely lean engine there can be a detonation happen before the actual "ignition".
What would cause of such a lean setting that would cause this? I would think that at some point would the bike even run with so little flue? Would you know it if you heard it?