Low RPM riding

General discussion of the BMW R1200RT/R1250RT
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jackronner
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Low RPM riding

Post by jackronner »

Seeking advice about whether it's OK to ride on a windless, level road at 2500 RPM or even a little lower?  I tend to do so around town to keep the noise down, but also used to love the slow burble of my prior big twins (BTW, is there any way to get an RT to burble like the old Beemers?  I loved their exhaust notes).  But is it more efficient fuel-wise?  As long as I don't feel it's lugging and there's sufficient power to maneuver, it's my "theory" that fewer RPM's means less wear-and-tear on the engine. Can someone with a greater technical grasp chime in?
bandytales
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Re: Low RPM riding

Post by bandytales »

jackronner wrote: Seeking advice about whether it's OK to ride on a windless, level road at 2500 RPM or even a little lower?  I tend to do so around town to keep the noise down, but also used to love the slow burble of my prior big twins (BTW, is there any way to get an RT to burble like the old Beemers?  I loved their exhaust notes).  But is it more efficient fuel-wise?  As long as I don't feel it's lugging and there's sufficient power to maneuver, it's my "theory" that fewer RPM's means less wear-and-tear on the engine. Can someone with a greater technical grasp chime in?

Well, set your dashboard to show instantaneous fuel consumption and monitor it in different gears at the same road speed, that will answer your question on economy. As to wear and tear, it could produce MORE wear and tear if the engine is running too slowly because you start to get a clunking effect which causes the gearbox to be working very hard with constant load reversal that it wouldn't see at higher revs. However, I OFTEN ride at engine speeds below 2500 when there is no load. When I want to pootle along, I don't want the engine to detract from that feeling, I want the engine just turning over slowly and effortlessly like the rider!
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David.
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Re: Low RPM riding

Post by David. »

The on-board computer (BC) accessed via the INFO button on the LHS handlebar switch only displays Average consumption.
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exportman
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Re: Low RPM riding

Post by exportman »

As long as you are not making the engine work ( eg just maintaining a constant speed on a level road) it will have little effect  just remember you have far less control.  You engine braking and next to no acceleration if needed.
You may get better fuel return but if I wanted better mileage I would by a smaller engine bike.
MEM62
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Re: Low RPM riding

Post by MEM62 »

Your engine will tell you if you are labouring it (ie not enough RPM)  Just learn to listen to it. 
bandytales
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Re: Low RPM riding

Post by bandytales »

David. wrote: The on-board computer (BC) accessed via the INFO button on the LHS handlebar switch only displays Average consumption.

Sorry.
Didn't spot the OP has a HexHead which only displays average consumption.
The Wethead displays instantaneous fuel consumption as well as average consumption.
gary45
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Re: Low RPM riding

Post by gary45 »

My 2018 has an up shift indicator you can turn on or have off, it has you shifting and driving at quite low rpms
jackronner
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Re: Low RPM riding

Post by jackronner »

As to the instantaneous fuel reading,  I'd always assumed re-setting this function by holding down the button while riding would start giving you real-time readings, no?  And, yes, I never get so low in the RPM range that I don't have a useful amount of acceleration handy at need.  I had noticed how the computer smooths out engine performance if you inadvertently slow down without shifting down.  On my old bikes, the bike would start balking to let you know.  So part of my concern was whether this tech would give me a false sense of security about low RPM riding.  I certainly don't go so low as to give me transmission lash, etc.
Dee Dub
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Re: Low RPM riding

Post by Dee Dub »

The boxer twin is very good at low rev cruising. 2500 rpm should be fine on a level road, constant speed. If you have previously owned high-revving Jap bikes, this may feel strange at first!
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