What's your RPM range?

[Shadow]

machines have been really good to me, what kind of a heartless bastard would I have to be not to return the favor.

It's a machine, it's designed to be used, not babied.

You will not hurt the engine, a good rev now and then does it the world of good, babying it just clogs it up.

A modern bike will take a lot of flogging and most sell their bikes well before they need engine work, so get out there and give it the berries.

 

[greywolf]

+1 lugging is worse for an engine.

With the FJR 88% of the torque is available from 3500-6000 and the torque curve is relatively flat , so for reasonable power this is a logical "normal " range of operation with little chance of detrimental side effects. 6000-8000 is where it makes a significant jump.

Past that both torque and hp drop quickly so not much need to beat the engine ..

 

[charismaticmegafauna]

With the FJR 88% of the torque is available from 3500-6000 and the torque curve is relatively flat , so for reasonable power this is a logical "normal " range of operation

As seen in the accompanying dyno-chart for the, much vaunted, 45* V-Twin:

The 'sweet spot' in the torgue curve is about 1,000 rpm wide. Compare that with the FJR's that's 2 1/2 times wider.

So much for: "the massive torgue of the v-twin"....?

These are the engines (the reportedly 'torquey' ones) that need a 6-speed tranny (just to be near the engine's operating range).

Good marketing -- you can't believe everything you hear.... :blink:

 

[Rolavine]

machines have been really good to me, what kind of a heartless bastard would I have to be not to return the favor.

It's a machine, it's designed to be used, not babied.

You will not hurt the engine, a good rev now and then does it the world of good, babying it just clogs it up.

A modern bike will take a lot of flogging and most sell their bikes well before they need engine work, so get out there and give it the berries.

Hey, I'm old this could be my last bike, going to one day make the transistion to the rascal scooter, maybe this is why I want it to last forever.

My bike does get to redline once in a while and a few rural roads where I have explored the limits of my own courage, but not the bikes (yeah I ride like a pussy but at least I'm faster than the cruisers).

I just don't do it all the time, heck if I did they would have put me on the traffic equivalent of death row.

 

[UselessPickles]

With the FJR 88% of the torque is available from 3500-6000 and the torque curve is relatively flat , so for reasonable power this is a logical "normal " range of operation

As seen in the accompanying dyno-chart for the, much vaunted, 45* V-Twin:

The 'sweet spot' in the torgue curve is about 1,000 rpm wide. Compare that with the FJR's that's 2 1/2 times wider.

So much for: "the massive torgue of the v-twin"....?

These are the engines (the reportedly 'torquey' ones) that need a 6-speed tranny (just to be near the engine's operating range).

Good marketing -- you can't believe everything you hear.... :blink:

How are you defining "sweet spot"? You also can't directly compare RPM ranges between bikes; you have to compare relative RPM ranges as percentages of the available RPM range. Like this...

I'll define "sweet spot" as the RPM range where 90% or more of peak torque is available. Using the dyno chart from a stock FJR here, I came up with the FJR's sweet spot ranging from 4.9k to 8.2k RPMs. That's a 3.3k RPM wide "sweet spot".

Using the dyno chart you supplied for some unidentified Harley/Buell, it's "sweet spot" ranges from somewhere before the beginning of the dyno run to 2.8k RPMs, then again from 3.4k to 5.3k RPMs. This Harley/Buell has 2 "sweet spots", one being at very low RPMs. The low "sweet spot" is what gives the perception of a "torquey" engine, because much torque is available almost immediately off idle. The higher sweet is 1.9k RPMs wide.

Ignoring the Harley/Buell's low end "sweet spot", the FJR's "sweet spot" is 1.7x the size of the Harley/Buell. But let's convert the RPMs to percentage of available RPMs:

FJR "sweet spot": 54.4% to 91.1% of available RPMs (covering 36.7% of the RPM range)

Harley/Buell "sweet spot": 59.6% to 93% of available RPMs (covering 33.4% of the RPM range)

The size and location of the "sweet spots" are actually pretty similar, with the Harley/Buell having an advantage of another "sweet spot" at very low RPMs. The difference comes from the overall RPM range and the gear ratios required to translate those RPMs to reasonable road speeds.

Comparing the dyno charts, there's a decent difference in peak torque values: ~86 ft-lbs for the FJR and ~76 ft-lbs for the Harley/Buell (FJR has ~13% more torque). However, the FJR can have lower overall gear ratios to convert its larger RPM range to road speed; this lower gearing further multiplies the torque advantage that the FJR has over the Harley/Buell. If the Harley/Buell was geared to achieve the same theoretical (RPM-limited) top speed, the Harley/Buell's gearing would be 1.63x that of the FJR, which leads to the FJR's actual torque at the wheel being multiplied by 1.63 relative to the Harley/Buell. That 13% torque advantage now becomes an 84% advantage.

 

[sporto]

Hey, I'm old this could be my last bike, going to one day make the transistion to the rascal scooter...,

Based on your comments on this thread, I have some bad news for you...I think it is time for you to head on down to the scooter dealer.

 

[UselessPickles]

If the Harley/Buell was geared to achieve the same theoretical (RPM-limited) top speed, the Harley/Buell's gearing would be 1.63x that of the FJR, which leads to the FJR's actual torque at the wheel being multiplied by 1.63 relative to the Harley/Buell. That 13% torque advantage now becomes an 84% advantage.

I should point out that cruisers are not actually geared that high, so the true advantage is less. If they are geared low enough, then the cruiser actually has the advantage in 1st gear (especially since it has a "sweet spot" at very low RPMs where our engines are relatively weak), but quickly loses that advantage when it has to shift into 2nd gear at 25-30mph while the FJR reaches its sweet spot and doesn't have to start shifting until about 60mph. Then if you launch the FJR at 4k RPMs, the cruiser is just screwed.

 

[charismaticmegafauna]

This Harley/Buell has 2 "sweet spots", one being at very low RPMs. ...almost immediately off idle. The higher sweet is 1.9k RPMs wide.

Aah, 2 power bands -- AKA a "flat spot"...

(nice work with all the numbers, tho...)

 

[UselessPickles]

This Harley/Buell has 2 "sweet spots", one being at very low RPMs. ...almost immediately off idle. The higher sweet is 1.9k RPMs wide.

Aah, 2 power bands -- AKA a "flat spot"...

(nice work with all the numbers, tho...)

If it weren't for that "flat spot", that bike would have one "sweet spot" that would cover almost the entire RPM range.

 

[v65]

For the record I prefer the FJR in the 5.5k-7k rpm range, lots of power there and still room before the rev limiter. Cruising down the highway 4.5k is good too.