V-twin (specifically) cruising RPM? At 45 MPH, for instance.

[He Man]

What I don't understand is why Ducatis run lower RPMs than IL4s. I mean wasn't the desmotronic thing invented for higher RPMs?

I think you ment, why our 2 valve ducatis run lower RPMs than I4s. 2vs just stop making power at 8k.
4vs make power up to 11k.
GP bikes make power up to whatever k it is that it makes power at.
Your run of the mill jap bikes have heavy springs to prevent valve float (though its still there in some regard)
Everyone else in motogp is using pneumatic valves.

[Spider]

I'll run my 992ds at anywhere from 3250 to 5000, after that I usually shift just to quiet down the engine! I have noticed that most gears like 3250 but 6th only really likes 3900 upwards (she'll lug and chug otherwise). For city use it's better to be nice and high at 4500 - 5500 then down low at 3200 because sometimes you need to squirt her through.

But at 45 mph, well I'd be happy to cruise at 4000

[Gunner]

Reference:

Reg Pridmore in "Smooth Riding -the Pridmore way" suggests on page 59 that Ducati twins should be in the 6000- 8000 rpm range for street riding

Being on the gas keeps the bike in the middle of its suspension range and in the heart of its power band

[herm]

^ +1

i do almost all of my riding between 5500-6500 rpm.
the bike (s2r1k) is smooth from 3k up, it just feels happy between 5-6k.
also, since no one else has posted it, my rev limiter kicks in right about 8700rpm. cant miss it.

[hypurone]

What I don't understand is why Ducatis run lower RPMs than IL4s. I mean wasn't the desmotronic thing invented for higher RPMs?

Primarily (for all twins) the reason the RPM range is lower, is that you have 2 LARGE slugs pounding away vs 4 smaller slugs. The reciprocal mass is wicked at higher revs on larger pistons, the piston speeds become unmanageable and tend to tear things apart sooner at stratospheric revs.

[hypurone]

Oh, and my RS likes 4.5-5.5 for a sweet spot at any constant speed. 5.5-6.5 for roll-ons or accelerating.

[hyphen]

depends on gear and speed or what you consider to be "cruising".  my idea of street cruising is an average 40-50 mph.  in lower gears my rpm limit for a cruise is around 3.5k.  in 4th or 5th it'll be between 5-6k.

[superjohn]

I usually stay between 4k and 6k, though I run a little higher on the M620 since the torque peak isn't until 6500 or so.

[MadDuck]

4.5k is like buttah. '98 M900

    +1

[Goat_Herder]

I usually stay between 4k and 6k, though I run a little higher on the M620 since the torque peak isn't until 6500 or so.

Maybe I am missing some finer point here.  But from I can see, the Monster 620 generates over 80% of its maximum torque at 3500-4000 RPM.  If you are just cruising around town, traveling at the constant 35-40 MPH, what would be the advantage of running at a higher RPM.  I usually just run at 3500 RPM and it has plenty of pickup with just a flick of the wrist.  Maybe you just like to enjoy the sound of screaming exhuast cans. 

Below are the power curves of the 620 and 800, found on Ducati.com.