Skid plate sound dampening

[octane25]

I recently installed an SW-Motech skid plate after reading a few positive reviews on here, and have been really happy with it - aside from one thing. The second I started the bike up I noticed a very annoying resonance/vibration sound reflecting off the skid plate. I could still hear it despite wearing earplugs inside my helmet, and even while accelerating at speed. I almost got used to it, but after two separate people asked me why my bike sounds like sh*t I decided I should probably do something about it.
 
I searched for a few options for sound deadening, but the results of each method seemed inconclusive. Then I remembered about a product I used a few years ago on a few car audio installs that I did, and thought I would give Dynamat a try.
 
Their new product, Dynamat Xtreme is supposed to be an improvement over the older version. Thinner, stronger adhesive and more heat resistant - so I'm told. I picked up a speaker kit for $30 CDN and gave it a shot.
 

 
The installation is very straightforward, just ensure that the surface is clean and that you leave cutouts for the brackets. You can see where the brackets were mounted from being installed for a few weeks, if you're doing this to a new skid plate just install the brackets and mark around them with a sharpie.
 

 
I also left a void where the exhaust headers come into close contact with the skid plate. The Dynamat is good for 300*F and probably not an issue when the bike is moving, but I can see that area getting too hot while sitting in traffic. It's a peel and stick product, that can be easily cut with scissors or a knife. The key is to cover as much surface area as possible, the instructions stating a minimum of 30%. Just do the best you can to get good coverage without going crazy. I spent some extra time to align the pattern but that's just my OCD. I was left with about an 8x12" piece left over for future use.
 

 
The end result looks great, with perfect amount of clearance around the brackets and directly under the lowest part of the headers.
 

 

 
Having started the bike, the improvement is immediately noticeable. The annoying sound is completely gone and the bike now sounds the same or better than it did before I installed the skid plate. I'm not sure if this is an issue on the Higdonion product also, but I imagine this would work great as well if it is. Just thought I would pass this on in case it helps anyone. Cheers. 
 
 
 
 
 

[troll]

I haven't noticed any resonance from my Higdonion urban cage, might be because they are steel. A few years back I put an aluminum SW Motech skid on my Super Tenere and it was very loud. Nice solution

[suncoaster]

Good solution, but is it flammable ?

[adjuster]

I like it.
 
Anything is flamable. Even the alluminum if you get it hot enough, and add enough oxygen.
 
But on this subject, I'd just get some longer mounting screws for the alloy plate. And cover the ENTIRE plate, cut out the holes for the vents, use what you have with a second layer along the lower part, it's going to "lower" the skid plate by the thickness of the Dynamat, but who cares? It's a few MM at best.
 
The entire thing covered would also allow you to put some edge trim around the alloy plate and the dynamat. (Car door edge trim for example.) Warm it up with a heat gun, and install with some 3M adheasive, and it's not going to move. And it will make that edge where the mat and alloy plate meet nice and tidy, while also keeping the mat from ever peeling loose.
 
The mat will further insulate the plate from the mounts, reducing noise even more than it has.
 
If you are worried about heat from the exhaust, get some alumimum duct sealing tape, and apply a few strips where it's near the dynamat. Should help to protect it from heat, and the underside of the plate will radiate any heat away pretty quick as well.
 
If you want to test it, take a small piece of mat, stick it on a similar scrap of aluminum and cover with alloy tape. Then hit it with the heat gun on high, and see when it melts, or catches fire. Temps can be monitored with a simple laser aimed infared meter that gives surface temps. (I have a Fluke copy from Craftsman, but Harbor Freight sells them pretty cheap and they work fine. Nice for checking tire temps across the tread, exhaust temps etc.)

[adjuster]

PS: Throw/stick some of this stuff on various parts on your bike. Air box? Panels that make noise? Windshield mounting areas that can resonate. Side panels. Underside of the gas tank. Underside of your seats. Line the "tool tray" plastic.. Lots of sources of NVH on motorcycles that are too expensive, considered too heavy for Yamaha or others to worry about.
 
It's like filling your bars with lead shot, it's dang effective as a dampener, but it's heavy and costs some money. Thus it's not done. Live with the vibes right?
 
Dynamat on the outside and inside of the air box in places would help reduce engine noise and vibrations too. Heck, apply some directly to the valve cover, and it would be interesting to see a resulting reduction in noise there too. (And if done right, you'd never even see it, especially if you removed the AIS system anyway.)
 
Sort of off topic, but a buddy of mine about 10 years ago, had a Polaris ATV that he bought second hand. It was bright red, and he wanted it darker, or camo even. He was asking me about painting the plastic, and it had some broken fenders and tabs, and the "poly" racks were pretty beat up. We pulled all the plastic with heat welding used on plastic bumpers etc. No sweat, but it did not look the most appealing. (And using typical automotive repairs on the parts would be fine till they flexed, then it would most likely crack the surface and look like crap.)
 
I sent him over to some buddies at the local Line X shop.  They shot it with Line X. Two versions of dark green on the fenders and dark brown on the racks. He put some new bars on the ATV, with dark grips etc. Even the head light cover was coated dark brown. The trick is it made some of the panels nearly 2x as thick as stock. And they shot both sides to cover the "red" base. The poly racks were black, so they only needed the brown to cover them, but it really made them super nice. The texture of the bed liner is perfect for hauling stuff if you don't want it to slide around much. Strap it on and it does not move around much.
 
It cost about 400.00 for it all, but dang it was a cool looking beast after that, no decals, just dang cool and talk about durable!
 
But the really super crazy part? It was WAY QUIET. The tire noise was much more noticed now than before, because the engine noise was nearly cut out by the bed liner. (He fixed that with a performance pipe, so it was loud again, but only at the muffler exit.) I swear it rode more secure feeling too.