dampening idea

GoldenMotor.com

Tim Mills

New Member
Oct 9, 2009
66
0
0
45
Mississippi
Hello everybody i will be starting my new build soon an have already gotten some great ideas from you guys. I thought of this idea the other day. i know these engines cause alot of vibration so i was thinking expando foam in the frame? My bike alraeady had holes made to run wires for taillight and headlight so i could actually fill most of the frame with this foam. Let me know what you guys think
 

philymitch

Member
Feb 7, 2009
95
0
6
Fresno CA USA
I have used expanda foam in my frame and my handle bars. using the foam in the handle bars reduced a lot of the vibrations in the bars. filling the frame with expanda foam really helped with vibs and noise from the motor. the foam will absorb alot of things you will be surprised hope this helped you.
 

xlite

New Member
Jun 18, 2009
735
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0
ny,ny
Two of the guys I built bikes for tried filling handlebars with Great Stuff. They both raved about the improvement but I saw no difference at all. My buddy who also rides these could not tell which bike had the foam in it during a blind test. Another fellow filled his tube with sand and it did make a difference.

The almost non existant mass of foam should not have any significant effect on vibrations.
 
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skjjoe

Member
Mar 9, 2009
393
1
18
Boerne Texas
be very careful not to get it in the bottom bracket that stuff is hard to get off.And i have heard of the stuff expanding into the bb and locking up the bearings.
 

bandito

New Member
May 22, 2009
783
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colorado
Youd be surprised how well a $20 suspension seat post helps and I weigh 215. I think GOD created gel grips just for folks on 2 wheels. I know theres better seats out there but Im satisfied with mine its leather and wide for the rear plus it has good padding.
 

Tim Mills

New Member
Oct 9, 2009
66
0
0
45
Mississippi
Hey guys thanks for your quick responses i will probably try all your suggestions and since i have to break my bike down to send it home i will jus be patient, paint it an all that good stuff i would rather take my time the first time so i will have more time to ride thanks guys .flg.
 

42blue15

New Member
Sep 18, 2008
136
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0
St Louis metro, USA
Somebody posted about the problem of the foam getting into the bottom bracket on motoredbikes.com.

I have tried to use this foam for filling other purposes and found that it does not fill nearly as consistently as you'd think.

What I would suggest would be to use some urethane sheet in your motor mounts somehow. It is risky to try to use rubber for motor mounts, because the fuel/oil spilled on them may chemically attack and degrade the rubber. Urethane is far more resistant to this problem. Stick to the harder durometers--60-70 or more.

Sorbothane is a premium type of urethane designed to absorb vibrations. It dampens much better than any other urethane or rubber out there. In the USA, Sorbothane (as well as plain sheets of urethane) can be ordered from McMaster-Carr.
~
 

bandito

New Member
May 22, 2009
783
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colorado
When mechanical engineers want to isolate vibrations they try to reduce the causes 1st, when that isnt possible due to the nature of the beast then they try to isolate the vibrations. I wonder why engine mounts on cars use rubber? Nuclear powered subs have almost every thing in them hanging or mounted by rubber mounts or other designs to minimize vibration travel. I wonder why they use rubber mounts instead of foam filled encapsulated hangars. Maybe automotive engineers havnt thought of foam yet.
 

xlite

New Member
Jun 18, 2009
735
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0
ny,ny
Nuclear powered subs have almost every thing in them hanging or mounted by rubber mounts or other designs to minimize vibration travel. I wonder why they use rubber mounts instead of foam filled encapsulated hangars.
Military has a propensity towards things that WORK.
 

Cabinfever1977

New Member
Mar 23, 2009
2,288
1
0
Upstate,NY
i used rubber under my mounts and taped them tight to the frame with black tape.
is still holding up and not wearing down and there is no engine movement.
 

diceman2004

New Member
Aug 26, 2009
564
2
0
Kitchener , Ontario
all the expanding foam i,ve seen gets hard when its cured ( harder than styro foam ) by harder i mean more brittle .

sorry if i sound so negative , but i don,t see how 5 ounces of brittle expanding foam can possibly make a difference that you can actually feel .

i think you would have better results by filling the ends of your handle bars with play-doh
 

GearNut

Active Member
Aug 19, 2009
5,104
11
38
San Diego, Kaliforgnia
A few years back I saw "liquid bar snake" sold in Harley aftermarket catalogs. It was some sort of epoxy rubber that you poured into the handlebars to reduce the infamous Harley hand numbing vibrations. I have only heard that it works, never a complaint that it does not. I haven't seen it for years. I wonder if it is still available?