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.
Does anyone ride between 6-7k rpm's?
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Anyone seen the Fortnine video on high rpms? Interesting stuff there.
Here's a belief and not an engineering principle.... get on your bike, take a ride and enjoy the thrill of motorcycling without worrying about engine wear if you exceed 2000 RPM. 
As an engineering minded rider I find the discussion about pros and cons and side effects of different operating regimes fascinating. Nothing wrong with having a civil thread about it and getting some insight from people with first hand knowledge of the physics of it
Hooligans will still hooligan
Cruisers will still cruise
And we’ll all enjoy our rides
Hooligans will still hooligan
Cruisers will still cruise
And we’ll all enjoy our rides
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Absolutely! As is typical nowadays folks want to make it either/or when it's not so extreme as implied by some here. Hooligans might (likely) sometimes cruise and cruisers might (likely) sometimes hooligan. I love riding twisties in the hooligan zone but folks seem to think I ride at 85mph down the interstate in 3rd gear just to ride in high rpm. WTF, who does that? When appropriate for my amusement I'll crank up the rpms. When not, I won't. It never seems to bother my 140K mile 2007.
I've been taught to run the RPMs higher when doing Twisties, maybe 6-7k. The thought here is if you need to drop your speed, you can do so by throttling down. If you apply brakes, it stands the bike upright which you don't want in a turn.
Other than that, if I'm on a 55 mph road, doing 60ish, I typically don't use 5th gear, just leave it in 4th. My rmps are around 4k.
Just my 2¢.
Other than that, if I'm on a 55 mph road, doing 60ish, I typically don't use 5th gear, just leave it in 4th. My rmps are around 4k.
Just my 2¢.
nu-uh.
classicrocker
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This is part of the reason that I asked the question
nu-uh? You disagreeing with his statement? How do you ride the twistes then?
RossKean
Well-known member
Don't think the bike "knows" whether deceleration is due to engine braking or wheel braking. Physics is physics and deceleration will have the same effect on lean (and trajectory) no matter what the input source might be.
Edit: Riding at higher RPM in the twisties provides better acceleration control to power out of turns or handle rapid elevation changes. Engine braking is easier than coordinating manual braking although trail braking (rear brake) can help with control.
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The bike does know whether you're rolling off or hitting the brakes. There will be much more nose dive using the brakes entering a turn as opposed to rolling off. In a higher RPM there is minimal need for using your brakes in the twisties. Read about The Pace. You can just roll on and off the throttle and thus eliminate upsetting the chassis.
The nu-uh was referring to Dafish disagreeing with tschutter. I'm interested in hearing Dafish's take on it.
The nu-uh was referring to Dafish disagreeing with tschutter. I'm interested in hearing Dafish's take on it.
RossKean
Well-known member
Not with typical rear brake trail braking. Yes for the front brake.
Keep in mind the FJR brakes are linked so you are actuating part of the front brakes while trail braking.
On the topic of what the bike knows, I would also assume that things like abs and traction control would have no authority over engine breaking.
Not sure how’d you’d end up locking the tire using engine breaking, just a thought about control authority
Another slightly off thought: on my V85tt there was a noticeable difference in lean-in when the rpm’s were higher that was presumably caused by the inertia of the rotating shafts (transverse mounted vtwin). I haven’t noticed anything similar on the FJR, might have to run some tests
RossKean
Well-known member
My Gen II doesn't have traction control and engine braking can absolutely cause you to break traction (although the wheel doesn't fully lock) - less so if you have a slipper clutch. Obviously, ABS would have no effect.
RossKean
Well-known member
Yes, but not especially strong braking on the front when lightly trail braking.
Should be doing most of your braking before entering the curve anyway and then power out.
Ross’s answer is near perfect IMO. I suppose i can add I find it smoother using throttle vs the brake, and there is a TINY amount of shaft jack that occurs at throttle up, but to 99.9% momentum is what it is. Of course the farther over we’re leaned the less “up” we feel on decel (either kind) and the more suspension loading occurs, but that’s not really the point.
Of course if somebody punches the brakes harder than engine decel, or is less smooth, than it will feel stronger, but as has been said physics is what it is, and aside from minor niggling the bike doesn’t know what force is slowing the wheel.
So why did you nu-uh tschutter? I'm confused because you basically said the same thing he said.
perhaps I communicate poorly. Let’s call it my fault and I’ll try to be more clear: I find engine braking and rear wheel braking indistinguishable. Tshutter stated braking stands a bike up while engine braking doesn’t. These are different thoughts, although he’s certainly welcome to his opinion.
Truthfully, mild front braking won’t either. Relative of course to how you have your compression set and your lean angle.
However, nu-uh was meant to imply to imply I didn’t care to write war and peace too, so imma gonna respectfully bow out now.
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