Consider a single vertical cylinder with the piston going up and down. A crankshaft counter-balance weight is pointed down when the piston goes up. If the balance weight is the same as the piston & pin weight, the engine is balanced but only at that point. When the piston moves downward, the balance weight is now pointing towards the front or rear of the bike. So you trade up and down vibration for fore and aft vibration. So older bikes had counterweights that weighed something less than the piston and pin weights. That was called Balance factor and engine builders added or subtracted balance weights for strokers, etcetera. So the compromise was that you ended up with somewhat less up/down vibration and traded it for some fore/aft. The V-twin makes it more complicated as the crank has to be counterweighted somewhere in the middle of the crank opposite two pistons whose motions are separated by 45 degrees. A compromise, as always, but the 45 degree V-twin is challenging to balance completely. Now go back to that single cylinder engine and think about rotating balance shafts. Remember that the crank weight rotates and causes fore and aft vibration. A single counterweight on a shaft rotating in the opposite direction could balance out the fore and aft imbalance. That works out at the fore and aft points of engine rotation but generates another imbalance at any other point in the 360 degree crank rotation. Reduced overall vibration - yes, but the engine still vibrates but just a bit less. Without going into a long discourse, two counter balancers can work better yet, but still far from perfect. The fact that 45 degree v-twin reciprocating motion is in two separate directions makes it difficult to completely balance out primary vibration with rotating counter balance shafts. There are many articles of riders complaining about softail vibration at higher speeds and Harley says the left some vibration in to please the riders but the fact is the engineers had no choice. Rubber mounts can be designed to work for certain vibration ranges. So Harley's with rubber mounts shake at idle but smooth out at speed - a wise choice. Now take the M8 bikes with single counter balancer to reduce vibes at low speed and rubber mounting to reduce vibes at speed - a big step in the right direction. The 2018 Softail with solid mounts and dual counter balancers will vibrate just as much as the old Softail, so be careful buying one. The smoothest Harley motor is still the V-rod, with dual counterbalances and rubber mounting.

 

Welcome and thanks for that. I think you'll find that the knowledge base here is vast and there are many that understand exactly how these engines and engine mounting designs work. You've not really broken any new ground here.

 

Well, I wish my bike didn't vibrate as much as it does. At 70mph, the mirrors are pretty much useless, unless the vehicle way behind me has their lights on. If I could figure a way to make them more stable, I could make some money.

My wife might like how it vibrates but I don't.

 

My 2018 Softail has good vibes, but it is noticeable smoother than my 2014 Dyna at all RPM ranges. I can see what's in the mirrors for a start.

So I think HD has done a good job with the balancing, while retaining some of the typical HD ride character - but not the shaking at idle which I quite like. Although at least on the new bikes I can put my gloves on the seat without them shaking off in less than a second.

By the way - paragraph breaks in your posts would be a good thing if possible....

 

Shovelhead will numb your hands at 80mph, 2017 RK I've yet to feel any real buzz at any speed. It's a nice change from years of riding my bone shaker.

 

If you handlebars are excessively vibrating you may want to check or perhaps replace the mounting bushings.
Also, shorter stem mirrors seem to reduce effect of the vibrations and the mirror "shake".

Years ago, some guys (not I) riding Shovelheads were sliding rubber hoses inside the handlebars in attempting to reduce the vibrations. Not sure if it actually helped but obviously some thought

Some say that the "THIRD GEAR" vibration delivers the desired result for the passenger!

 

My ex used to lean in and yell in my ear " Don't shift yet ". And the hose didn't work...

 

Hands off my vibration Thessler!

A few complain, but most HD riders enjoy the good vibes. Personally my '92 FXR and my '18 Heritage both vibrate the perfect amount even though they use drastically different mounting systems. If it was as smooth as a Vrod, it wouldn't be in my garage.

 

My Honda had weights in the end of the handlebars to help counter vibration I don’t think either one of my Harley’s has that. That being said my 96 Evo softail vibrate so bad at highway speed but it comes through my foot pads more than the handlebars. I have replaced the floorboard pads thinking this would help but it didn’t. So now I’ll just ride her around town and save the Electraglide for the long hauls.

 

My bike is 3 years older than yours. Granted it's a touring model, with the batwing fairing. Your mirror vibration at 70 mph is most likely due to wind buffeting (I have none). At 70mph my bike vibrates less than at idle.