Hi, appreciate anyone with info on running HD engines at higher revs, other than the increase in the engine, cams, exhaust sound levels and fuel consumption, anything else to be concerned about?

 

What do you consider to be higher RPMs?

 

Changing above 2500rpm is minimum and running/shifting above 3000rpm usually when shifting gears. But my query is, using the 999's, running at anything even at very low speeds in traffic, you have to keep the revs above 2500rpm and in 1st gear, just causes a lot more volume to other road users but wanted to understand if others have same queries? Changing to 2nd is not an option unless you are moving over 25/30mph as the revs too low and in very slow traffic jams at less than 25pmh as an example, you have to run in 1st and higher revs.

 

I don't think there's any issue with it other than the higher noise and heat. So it's not great for other road users at low speeds as you say - but shouldn't hurt the motor unless it is causing overheating in slow traffic which could definitely happen.

I used to ride my Twin Cam at 2.5K+ all the time - apart from in very slow traffic.

Sadly, it doesn't look like the 999 cams are a good choice if you are in slow traffic......

 

Around 5500 RPM is reaching the limits of a long stroke Harley engine.
For a couple of reasons.
Inertia-
and piston speed combined with rod ratio
With a long stroke it takes way less RPM to reach piston speed to the speed of sound than short stroke.
Inertia- I am told one gram weighs 30 lbs at 6000 RPM 3 inches from center.
Even if that is not right, it illustrates what the long stroke Harley engine is up against being there is no way to balance it.
Experimenting with small to big stokes on paper, one will readily see how the engine with the long stroke is up against as far as high RPM.
OK Race engines- Now for something completely different-
welded cranks, super lightweight this and that it can exceed the usual limitations, ...for awhile


https://www.musclecardiy.com/perform...mance-engines/

http://www.csgnetwork.com/pistonspeedcalc.html