I was out ripping around on my FXDWG yesterday, actually doing carb tuning, and did a full WOT run from 1st>2nd>3rd. When I hit third, I felt something give and immediately got vibration through the pegs and handgrips, just like has happened before when the front motor mount failed. Motor is running great, so I'm pretty sure nothing went wrong there.

Checked the front motor mount this morning and, sure enough, the rubber is touching the motor mount bracket at the top of the rubber. Just replaced it about 1300 miles ago with a stock HD motor mount. Guess its time to go with a Vibra-Technics. Would like to get feedback from anyone who has installed the Vibra-Technics on a Dyna with a Jagg 10-row oil cooler (no fans) if there are any problems with clearance or interference with the adapter plate, oil lines or cooler radiator.

Also, can anyone tell me the symptoms of the rear motor mount failure?

 

My front motor mount did the same thing today.

Closer inspection shows the rubber has been cracked. Must have finally just died.

 

I can only tell you what a dealer told me regarding a rear mount failure. Two ways to check are put a passenger on the bike with you and do some slow corners in a parking lot. A bad rear mount will make the back end wander.

Second way is to jack the bike up by the frame and check to see if the rear wheel comes up perfectly vertical. If if comes up leaning to either side the mount is bad.

 

When my rear motormount let go and pothole or driveway entrance would cause a clunk from the rear end. When I got underneath it I could see the motor was leaning on the frame. The vibratehnics hadn't been invented yet so I went with stock front and rear , that was 2 years ago.