That shake is a byproduct of the two-connecting-rods-one-crankpin arrangement. This design makes is near impossible to counterbalence the engine to smooth things out, so instead of trying, Harley leans into it.
Harleys have a 45 degree Vee design that by nature will vibrate more than most any other motorcycle engine design plus they are larger than most other bike engines.
As a result, after the first cylinder fires, the second has to wait until the shaft has completed 315 degrees of rotation. Then there is a 405 degree gap until the first cylinder fires again. This asymmetrical arrangement is what gives Harley engines their distinctive, deep bass rumble.
Lightening the flywheels is a common performance trick, so the engine can accelerate faster, but the idle speed has to be turned up higher so it doesn't stall. As to why they idle rough, it's because the two cylinders share a common crankpin on the crankshaft, so it fires irregularly, much like your heartbeat.
Some say it only happens on Harleys (mostly on the Road King, Ultra Classic, the Electra Glide and FLH series), but actually the wobble can happen on any bike and can happen with either the front or the rear of the bike.
And, after reading a whole bunch of stuff about the matter, I found a pretty clear online consensus: Motorcyclists rev their engines because they don't want to stall — especially with new or recently repaired engines that have not been “broken in” yet — or, in the cases when that probably isn't an issue, because they' ...
Mainly blipping the throttle is used on the downshift to avoid the rear wheel compression-locking. Without getting too technical, the lower the gear the higher the engine revs for the same bike speed.
It's simply a way of showing camaraderie with other riders. A wave or nod is our special way of saying hello and showing solidarity. Motorcyclists are often outnumbered on the road, so it's nice when riders show that we have each other's backs.
Undoubtedly, Harley-Davidson motorcycles are some of the loudest in the market. The sound level of the average Harley is around 70 decibels to 80 decibels.
Larger motorcycles, like Harley-Davidson, can usually take more miles without their engines being worn down as quickly. For these bikes, the high mileage point is around 40,000 to 50,000 miles.
It is associated mostly with low back pain and is one of the strongest risk factors for low back disorders. It occurs when workers sit or stand on vibrating seats or foot pedals. Prolonged exposure to high levels of WBV causes motion sickness, fatigue, and headaches.
Vibration can be caused by one or more factors at any given time, the most common being imbalance, misalignment, wear and looseness. Imbalance - A "heavy spot" in a rotating component will cause vibration when the unbalanced weight rotates around the machine's axis, creating a centrifugal force.
Phantom vibration syndrome (PVS) refers to the false perception that one's mobile phone or other technological device is vibrating when it is not. Most often associated with excessive mobile phone use, it has been described as a tactile hallucination as the brain perceives the vibration that is not present.
According to the YouTuber, Honda CB350 has the least vibration among the three bikes. At number two is Meteor 350, which had increased vibrations at higher rev speeds.
In order to reduce vibration and improve the dynamic performance of the shafting, a flexible coupling is used to connect the engine crankshaft with the generator input shaft, which is composed of a spring and a damper in parallel.
We checked with a Harley factory technical expert on lubrication and were told there is no scientific reason for long idle times before riding.
Engine speed up to 3,500 RPM (7,000 RPM for VRSC™) in any gear is permissible. Drive slowly and avoid fast starts at wide-open throttle until the engine has warmed up. Avoid lugging the engine by not running the engine at very low speeds in higher gears. Avoid hard braking.
Generally, most motorcycles will comfortably shift at an engine rpm of 5,000-7,000.