Quieting a skid plate on a DS bike

[Mark P]

This isn't related strictly to Pentons but I have a noisy skid plate on my KLX 250. Right now I have four coats of 3M undercoating on the top of the plate and will reinstall it with rubber spacers at the mounting points. Any suggestions how to quiet it more are welcomed. It howls at certain cruising speeds on pavement. Thanks!

[t20sl]

I have always used RTV silicone.  Depending on your tastes put a layer of cling type sandwich wrap over the part (skid plate or frame rails) you don't want RTV to stick to.  Put a HUGE bead along bottom of frame tubes.  Bolt on skid plate with extra washers (1 thick or 2 thin ones at bolt locations that draw plate to frame on bottom.  Snug bolts and let RTV cure for 2 days.  Remove plate, remove extra spacer washers, remove cling wrap and reinstall plate with standard mounting hardware.  The etra thickness of washers that you remove will allow skid plate to draw tight against the RTV and thus provide good dampning and should reduce sound and vibrations.  If you don't use cling wrap you won't get skidplate off without cutting RTV.  
Ted

[Mark P]

Thanks Ted! Aside from the oil drain plug hole on the bottom, this plate is completely solid(no holes). Do you think drilling some 1" holes in it might help also?

[Mike Hufnagel]

I always used strips of rubber.   Does the noise occur with the engine off?  

'12 Husaberg TE300
74 Yamaha TY 250
84 Yam IT200
75 Jackpiner w/ 250 eng.
82 KTM GS250II (import)
82 KTM 495 (2)
98 KTM 300mxc
04 KTM 125 SX
00 KTM Duke 2/rd. racer
06 KTM 950 Adv.
08 Suzuki DR70Z

[t20sl]

Mark:
I don't think holes would make a difference.  It might change the resonance of the noise but I think the silicone works great and have never heard any noise other than rocks hitting the plate.  On my PUCH I used an old aluminum street sign which is very tough aluminum and  attached skid plate with silicone (no cling wrap) because there is no drain and no reason to remove it.  Still, if I were you I would make it removable.
Ted