2006 Electra Glide.

Between 1800-2000 RPM my fairing shakes like mad. Its ONLY in this range, but its violent enough to shake my instruments enough that I cant read them, my 3 cell pouch bounces and my windshield shakes. I took the fairing off tonight and found all the supports were intact. (I gave all the screws an extra 1/4 turn to snug them down). Other than at the 2K mark, vibrations seem normal. Ive seen the repair kits, but my mounts arent cracked. Is there such a thing as reinforcing them?

I recently replaced my motor mount with a Drag Specialties mount. That stopped all the engine shaking at idle, but seems to have made the 2K vibration worse. Im also running a 10 inch freedom shield and a Harley 3 cell fairing pouch.

Do I REALLY need to buy one of those 100 dollar engine mounts or should I be looking elsewhere at other possible causes?

 

Sounds like it might be motor mount related if all the braces are good. Aside from the rubber motor mount, have you checked the engine mounts? Unfortunately, some motor mounts cause more vibes when replaced. Might have to try a different one.

 

The drag motor mount sucks. You may have the center bolt too tight. You may need a better motor mount. I know I do. Have you checked inside the fairing for broken fairing mounts?

 

Yeah, I took the fairing off last night and all the fairing mounts were good. 2 of the Allen bolts were ever so slightly loose (I gave them another 1/4 turn) but I don't think that would be enough to cause this kind of rattle. Ill try and loosen the center bolt a smidge. I'm really trying to avoid spending 100 bucks on a engine mount.

 

I too have a rattle in my 2013 and have checked brackets etc. I have chalked it up to having added an amp and larger speakers. Everything is solid but at a certain rpm when slowing, I get a rattle.

 

By tightening up your motor mount you’ve just transferred that vibration elsewhere in the machine. The fairing just happens to vibrate at that particular frequency. The motor is supposed to move a good amount at idle, there is nothing wrong with that. My solid mounted shovel will damn near clear the front tire off the shop floor at idle. A rubber mounted V-twin is a beautiful thing. I’d get a new factory replacement mount and reevaluate. Harmonics are hard to diagnose. Everything that rotates or oscillates has a critical speed. Getting excess vibration out is good, but remember it’ll never be Honda smooth, not supposed to be.

 

Exactly. You've basically taken the torque frequency and transferred it from the engine to something else. I did power train engineering for years. I've seen people chase this issue in NVH (noise vibration and harmonics) test cells. Where the noise from the valves gets fixed, but now the crank whines at a certain rpm because the frequency is pushed to the next weakest point. With a HD engine they are a very long stroke which is why they shake so damn much. But if you dampen that too much you'll end up sending it elsewhere. Likely you'll end up chasing the tail for awhile as well. I've seen guys buy super strong engine mounts only to see their bars shake so bad their arms go numb. Look into different styles of engine mounts and read all the reviews. They should also give you stiffness of the mount isolator or you could always contact the manufacturer.

 

Yep, a mile long stroke and sheer rotating mass is what you’re working against here. I wish the offered some sort of hydraulic engine mounts. A heavy viscous fluid does a much better job than rubber in that application.

 

I would pull the front fairing & check ALL the braces. They are prone to breakage. I replaced a right side (of bike) internal brace 2 separate times on my '99 Ultra.

 

Good call dude. I went back tonight and put the fairing back on. (with everything inspected and tightened) I then backed the center bolt off and re-torqued to the factory recommended 20 ft-lbs.

The 'rattle' is now confined to about 1400-1500 RPM's and is 85% less than last night. It still has a small rattle 'sweet spot' but its now FAR more acceptable than before. Thank you!