Author Topic: skid plate resonance?  (Read 129 times)

Offline Eville Rich

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skid plate resonance?
« on: July 17, 2017, 11:49:00 am »

I have an Altrider skid plate on my 2016 S10.  I get what I think is a resonance from the skid plate, most obvious between 3k and 4k rpm in 4th through 6th gears and in the first half of throttle.  It's there at other times, just most obvious in those conditions.  While I'm pretty sure it's just the skid plate, I want to make sure I might not be overlooking something else, like something in the clutch.  I ride with earplugs and it's still pretty loud.

I've been able to ignore it, but this morning was a little overboard.  It also helped me hone in on the skid plate as the likely offender.  I was following a dump truck at a reasonable distance for about 5 miles.  I could "hear" the changes in the dump truck's speed via the resonance.  There's not too much else on the S10 that would vibrate like that, other than the skid plate.  My guess is that the low-frequency rumble was getting picked up.

I see that folks have used Dynamat and maybe other materials to reduce skid plate resonance.  Any other tips for the Altrider skid plate?  I'm going to check all the connections, but it felt solid after my commute.  On my WR250R I improved things a lot by adding rubber washers to the connectors, but that is a totally different setup to the S10, and I don't think a viable solution.

Thanks much,
Eville Rich
2016 S10
2015 WR250R

Offline AVGeek

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Re: skid plate resonance?
« Reply #1 on: July 17, 2017, 12:25:24 pm »
I think the resonant damping material is the way to go.  Everything has a harmonic frequency, so changing the mass will change that frequency, usually to one below our audible threshold.
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Offline Sierra1

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Re: skid plate resonance?
« Reply #2 on: July 17, 2017, 01:54:08 pm »
I'm thinking it may be a combination of the skid plate, and something else....tires?  I have that skid plate, and Battle Wings, but no noise.  AVGeek is right about EVERYTHING having a harmonic frequency, but there are a bunch of Teneres with Altrider skid plates without the buzz.  Logic would indicate there must be something, however minor, different with yours.  Good luck.
In the stable:'17 TENERE ES; '14 FJR ES; '86 FJ 1200
Out to Pasture: '77 XS 360; '81 SECA 550; '00 KZ 1000P; '04 BMW 1150 RT-P; '11 ST1300PA; '11 KLR

Online WJBertrand

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Re: skid plate resonance?
« Reply #3 on: July 17, 2017, 02:53:55 pm »
I think the resonant damping material is the way to go.  Everything has a harmonic frequency, so changing the mass will change that frequency, usually to one below our audible threshold.

Agreed.  I lined the inside of my skid plate with Dynamat and it really quieted it down. I think a lot of noise is just reflected engine noise.  Besides a quieter ride, I think the presence of the Dynamat material will help cushion the sump a little should there ever be a large enough impact to force the plate into contact with the engine.

All of these bash plates seem to be made of large, flat pieces of featureless material, this is bound to act like a sounding board.  I think a ribbed design would not only be quieter but potentially stronger as well.
-Jeff-
Ventura, CA
2015 Yamaha Super Tenere ES
2005 Honda ST1300A

Offline Ironhand

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Re: skid plate resonance?
« Reply #4 on: July 17, 2017, 03:47:54 pm »
I had the same complaint about my Altrider.  I stuck a strip of neoprene padding intended for race bike seats on the inside of mine and solved the problem.  A Dynamat-like product should do the trick. 
2015 Ural Gear Up
2012 Super Tenere
2003 FZ1
1974 RD350

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