There are definitely some Dynas that seem to have issues with vibrations. I've got one. While most find it an irritation to say the least, I'm curious as to which RPM ranges the vibes seem to be the worse..

For instance, for my bike most of the vibes are from 2000 to 2500 and mostly during decel tho it can also vibrate pretty good on light acceleration while going up hill.. The bike I have is pretty heavily modified so I'd expect some increase in vibes.. I would guess it's also important to note when the vibes started. Not really sure when my Dyna vibes began to bother me but they seem to be creeping up. Could simply be me..I've even pulled the cam cover to check crankshaft runout and it's still good. Added the front spacer can help but it's still there. New front mount made no difference. Vibratechnics seemed worse in the 2000-2500 but better 3000-up. Heck I swapped the road rage for a set of pro-streets thinking the weight of the RR was causing it.. Second ride on with the new pipes and the rear exhaust bracket broke on the front pipe.. Heck I've even rubber mounted the CV51 / SnS tuned induction air cleaner to see if it would help.. Might even try pulling off the SnS air cleaner and going back to the original cv51 AC to see if it helps.. The only reason I bring up the AC is that the ends of the filters vibrate up and down pretty good at 2300.. Might be part of the issue.

Another instance, I guess that Switchbacks had the issue early on and some mods came up to help.. The vibes may simply have been noticed at one time.

Anyone else want to add information about vibration issues on their Dynas?

 

I've been through it all myself as well. Several muffler and entire exhausts from light to heavy, different mounts now running vibra technics, engine is no longer stock now 106 w s&s crank, entire vehicle alignment. I can't tell you when exactly it happened but I used to be smooth at 2400 and had a nasty vibration around 2800, then smooth 3200 and up. Now it's like you pretty vibration heavy close to 2400 but nice everywhere else. I much prefer it this way. 30T pulley up front, adding a 68T rear soon and i won't be at the low rpm range anymore. I believe the motor mount swap was the main contributor to the shift in RPM at which vibration is heaviest but i have no data to confirm.

 

I feel it on my Switchback on acceleration, as the engine passes through 3000-3100 rpm. not enough to bother me.

 

I get the obvious "chunky" vibration at idle. You know, where it look like it'll shake the mirrors, and controls right off the bars. Everything smooths out once, I take off. Then, as I bring it up to about 2800-3000, I get a kind of nasty buzz vibration. Oddly, this seemed to happen once I put my full fender on let month. Well, I actually can't say for certain that the fender was the cause, but I noticed the "buzz" vibration the same day that I put the fender on.

I popped the HD 1/4 fairing off about 2 weeks ago to change the headlight, and now it seems that thing shakes a lot on decel... I am little less concerned with that, because I can't remember if it did it before, or not. Plus, it's a removable part, so it's bound to have some vibration.

The biggest change in vibration was when I did my "stage 1" upgrade. The stock bike had a terrible vibration between 2500 -2900. Stage one got rid of that.

 

I have some vibration as the RPM's rise and fall through the 2000 - 2400 range. Above 2400 she begins to smooth out quickly and 2500 and up are surprisingly smooth but above 4800 RPM I'll begin to pick up vibration again.

The vibrations are not at all excessive, just noticeable as the bike is so smooth in the 2500 - 4800 range. If your vibrations are more noticeable on decel you may want to check the vehicle/engine alignment. Before I did the alignment the vibrations were much more pronounced, especially on decel. But a new front isolator, alignment, and shimming the front isolator so it could sit where the alignment wanted it to be turned this bike in to a very smooth machine...

 

My bike is smooth from 2200 rpm to 5500 rpm in any gear but 5th. It is not to bad but you can tell it is there but she will smooth out in 5th gear from 3000 to 4000 rpm then she will start vibrating again. Now when I ride 2 up she most definitely vibrates more. I was thinking just more load on the motor. Thinking of trying the Predator mount but do not want to spend $250 and make the vibration worst. Anyway it really does not bother me expect 2 up.

 

Mine is pretty bad in the narrow band between 1900 - 2200 rpm, then again around 2800 - 3200. Above that it gets very smooth, and it's pretty good between those two ranges. I've tried all sorts of things... Shimmed mount, Predator mount, rear wheel alignment horizontally and vertically, tire pressure, etc. At this point point I've pretty much ruled out most chassis vibration and believe it all to be actual engine vibes. I've adjusted and checked both belt and primary chain tension, loosened and re-torqued everything exhaust related, even played with different ignition mapping. My engine just vibrates in those ranges. I don't really believe it would be different if the engine was on a bench. For this reason, I don't think of all the different mounts etc. as things that will change the engine's vibration, but rather as things that separate the vibration from the frame. I like the predator mount a lot, because it did improve handling noticeably. But engine vibration still comes through the pegs and seat noticeably in the same ranges. I recently swapped in the OEM front mount for a couple of days; handling declined, vibes were almost the same.

I just installed a Custom Cycle Engineering top mount (which is rubber mounted), but I haven't really had a chance to ride it yet... It's this damn heat and humidity...

 

I am thinking like you are. The engine just vibrates. That's why this winter I am going to have my crank trued lightened and balanced. By the way my vibration is only in the pegs. Seat and bars are smooth.

 

FWIW I wouldn't lighten the crank but balancing may help.. Lightening will likely make it worse.. If you can lighten the reciprocating weight, pistons, upper ends of the rods, etc, that will help.. When HD first start making twinkies, they used pistons, pins, rings and clips somewhere around 1200 grams. When they went to 4 3/8 stroke they dropped the weight to about 1000 grams. I've been thinking about redoing my motor as a 117/113 with a 4 3/8 crank and using lighter pistons.. It currently has a 4 5/8 stroke crank that has been balanced to heavier pistons. I'll probably weight until the motor needs a rebuild tho.. It runs great and runs nice and quiet..

 

Mine is seat and pegs, but bars are completely smooth as well.