Yes, it will. Bad enough that you have to worry about everyone else out to kill you, sometimes your own bike is trying to do it too!
On Fri, May 13, 2011 at 11:07 AM, Kyle Munz <[email protected]> wrote: > If it's a light that I know is a long one I'll pop it in neutral, otherwise > I'll just hold the clutch. One word of warning though, sometimes that > neutral light with LIE TO YOU. Always assume it's in 1st or 2nd and let off > the clutch slowly just in case. > > @ Hank, on the topic of lugging killing engines more quickly than high-revs: It's the relationship between BMEP (brake mean effective pressure) and mean piston speed that determines this, really. In order for an engine to produce power at lower RPM (which it's trying to do if you're lugging it) the average cylinder pressure over time has to be higher. This pushes the rings more firmly against the cylinder walls (since cylinder ring tension is a function of cylinder pressure) which causes higher wear. At higher RPM, even higher power outputs, you actually have lower average cylinder pressure. Valve timing and fluid dynamics, coupled with mean piston speeds, means you actually get lower compression for a lower base effective pressure (BEP) and lower BMEP. Ring tension is lower, and thus your normal forces against cylinder walls are lower, but you're covering so many more strokes in a given amount of time that your gross wear is higher. Typically cylinder wear @ RPM maps have a peak early on, then take a bit of a dive, then start climbing again rapidly as RPM goes higher than typical "cruising" RPM for that engine. They also have a peak @ idle, which is less a function of pressure and more a function of poor lubrication pressure and poor fuel/air mixing. An interesting thing to note, with regards to all this, is the apparent disconnect between this information and the longer lifespan of diesel engines (historically speaking). Diesel BMEP for a given power output can be /3-4x that of a gas engine's/ rating, because it produces the power so low in the RPM band than the typical gas engine. Early diesel lubrication standards addressed this, and the more regular use patterns (more steady-state running and such) helped naturally overbuilt designs last for what felt like forever, giving us things like a Detroit Diesel two-stroke that would run for a million miles while the vaunted SBC would need almost ten rebuilds in that same lifespan. As gasoline technology has improved and gas engines have started producing more torque down low, their wear ratings have naturally improved by the simple fact that they don't /have/ to operate at 5k+ RPM to produce a usable power level anymore. That's also provided a lot of FE improvement as engines downsize for the same market segment. Was a time when a mid-size car would have had nearly an 8L engine... anywho. TL; DR is this: Engine technology is frikkin awesome! -Kurt -- You received this message because you are subscribed to the Google Groups "Nighthawk Motorcycle Lovers!" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/nighthawk_lovers?hl=en.
