I read a review from Motorcyclist magazine about the 1986 Softail Custom, which is an EVO. The review was done in the mid-80s. The review said some interesting things. See quotes below:

"We had been lulled into thinking the 1340cc Harley engines had to be rubber-mounted to be livable; the FXSTC proved us solidly wrong with its rigidly mounted and more than tolerably smooth engine. The bike feels tight-much more so than the FXRD with Rubber-mounted engine that we tested last month."

"Engine-vibration control is superior than on any of the rubber-mounted FX twins we've tested..."

I always thought the solidly mounted bikes had the most vibes. Does the above sound accurate?

 

I had a 1987 low rider and a 1988 softail custom. Both bought new. Rode both many times. By far, the rubber mounted low rider is a smoother ride.

 

It's odd the reviewers would be so off. Both types of bikes are from the same manufacturer. Maybe they didn't rev them too high and the softail was smoother in low and mid RPM ranges.

 

It has always been that way with reviews of any product. You always have to consider prejudice no two bikes are created equal. I for one never focused on vibration simply because a Harley twin is a big bore long stroke odd firing engine some vibration is a part of the lure for me always has been.

 

My current Evo Softail Springer is much smoother than my Shovelhead was. There's a little buzz to it on the highway above 75mph.

Newer twinkies are smooth of course. As are Honda Goldwings. "Yawn!" I don't ride Harleys for smoothness though. The slow, lumpy, big block feel to them is part of the allure.

 

I had a 91 FXSTC and a 93 FXLR. No comparison, the Softail shook like a ***** in church. My mirrors were a blur at highway speeds and the dash mounted speedo shook so bad I didn't bother to look down at it. The FXR was by far a smoother ride but by no means a touring bike. Having said that, I'd like to have both of them back.

 

I had a 1980 FLT and a 1992 FXR. Both rubber mounted, 80", 5 speeds... Both smooth as a baby's butt at any kind of speed. Both rumbled nicely at low RPMs. Both were set up with single fire ignition. The FXR still had a nice rumble at highway speeds.

I spent a lot of saddle time with a friends 90's Heritage Softail. It vibrated more than either of the rubber mounted bikes. But was far from intolerable! In fact, it was really pleasant to me. Realistically, it wasn't crazy different to me either. It just had a little bit more of a vibration to it... a little bit.

I also used to own a '68 flatside shovel that was in a rigid frame. That guy shook pretty good.... A heck of a lot more than the others I've mentioned!

I am always confused when reviewers complain about the vibrations of a Harley. It's part of the charm to me. Sure, it makes Loctite your friend, but I've never found it uncomfortable. I just finished an MSF course on a little Honda 250... now that buzziness was irritating! LOL

 

Rubber mounted bike engines will shake more while idling due to the mounts. That's not really vibration. But riding along at 60-75mph on my EVO Softail will numb my hands after a while. Not so with a rubber mount. I know. I put over 50K miles on both my 88 FXSTC and 87 FXLR. I even added a Dynatek 2000 ignition with single fire. It helped a lot. But the FXLR was still smoother.
It's anybody's guess where these reviewers get their ideas. I ignore them.

 

I've had three different motors in my Softail during the time I owned it. Each one had totally different vibration characteristics. I think it depends on the tolerances of the individual parts, and how well balanced they turn out to be. In my experience, it's pretty much "luck of the draw" whether you get a smooth Evo motor or not, as the factory doesn't really "balance" each one individually.

 

It seems like they should balance each one. "Luck of the draw" doesn't sound too good to me. I want to know what I'm getting. I guess a shop could "balance" it if need be. It shouldn't be necessary on a new bike though.