Reply to thread

Help Support Yamaha FJR Motorcycle Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Message: <blockquote data-quote="#Rocket" data-source="post: 1466800" data-attributes="member: 98498"><p>As a mechanical engineer and mechanic I have designed, specified, and maintained industrial, high performance, agricultural, and recreational machines for decades. Downshifting with moderate RPMs is factored into the design; however, the wear of unnecessary high RPM (especially sustained) is very real. Higher RPMs cause, among other stresses, additional oil shear degradation; therefore, it breaks it down faster--lubrication is less effective, rings wear more, cam lobes have less protection,  and bearings run hotter. The variables that affect wear are many and complex, but from a first principles perspective the influence of RPM is a nonlinear variable that becomes dominant at high sustained RPM (e.g., 70% to 100% or redline). These machines are optimized for a range of RPM that balances performance against acceptable reliability and longevity. If a rider can use reasonable downshifting for engine breaking and also cruise at 4500 RPM (50% or redline) the bike will last a long time with good maintenance; however, if the rider chooses an average RPM regime that is more like cruising at 6500 RPM and bouncing downshifts off redline, relative wear will be about 200% higher--instead of the engine lasting 150,000 miles it would be more likely to last 75,000 miles with  acceptable performance and reliability. These are general engineering principles, not beliefs.</p></blockquote><p></p>

Verification