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Old 11-20-2012, 09:20 PM   #211 (permalink)
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Motor Mount Shims

I did my new to me 96 all stock Super Glide with 34K miles on it. I put 4 1/16th shims in last week and got a very noticable reduction in vibes. This was with a new front motor mount. The top bolt hole in the original front mount would only take about 5 pounds of torque do to stripped threads so I replaced the mount. When I shimed it last week it looked like there might be room for 1 more 1/16 shim so tonight I got back out there and put in 1 more shim for a total of 5/16" . This made a noticable difference too. The bike is now MUCH smoother then it was through the RPM range (no tach) I still get a seat buzz between 60 and 70 in top gear, will probably try an Air Hawk to see if that helps with the seat buzz.

Thanks 84FXRP for all your efforts on this. Bruce
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Old 11-21-2012, 05:45 PM   #212 (permalink)
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Thumbs up been there, done that.

Quote:
Originally Posted by 84FXRP View Post
Sorry for the long post, but I have cured my Dyna’s vibration problem for about $10 in materials and I thought others might benefit from my approach.

I have a 2005 FXDI with a HD 95 inch Stage I kit.

Like some others on the Forum, my bike had, what I consider, excessive engine vibration transmitted to the handlebar, foot pegs, and seat. The vibration was especially evident below 3000 rpm. At idle, the handlebars jumped around excessively.

I followed the Service Manual procedure for vehicle alignment in an attempt to reduce the vibration. Alignment includes loosening (but NOT removing) ALL the motor mount attachment bolts, and then running the motor for 5 seconds during which allow the mounts to align themselves to the frame. The motor mount attachment bolts are then retorqued to spec. The procedure helped a little, but did not cure the problem. I also looked at other changes that might address the vibration problem such as “Bar Snake”, different length handlebars, handlebar mount bushings, etc. All these are Band-Aids on the fundamental problem of too much vibration.

A few weeks later I was thinking about the motor mounts and the alignment procedure and was struck by the cause/cure of the vibration problem. Any elastic motor mount, like the Dyna’s, has a limit to how much vibration it can absorb. Engine movement in excess of this limit is transmitted through the frame to the handlebars, foot pegs, seat, etc as vibration.

What struck me was that when I did the alignment procedure and the mounting bolts were LOOSE, there was a gap between the mount and the frame. Tightening the mounting bolts caused my front motor mount to be PULLED forward to the frame as the mounting bolts were tightened. I noticed that when the mounting bolts were torqued, the frame was also deflected somewhat.

THE ELASTIC TRAVEL OF MY MOTOR MOUNTS WAS LARGELY USED UP JUST BY BOLTING THE MOTOR MOUNT TO THE FRAME.

Any movement of the motor would not be absorbed by the mount – the elasticity of the mount is already used up before the motor is even started. Hence any engine movement is transmitted to the frame and is felt as a vibration. This would also explain premature failure of Dyna motor mounts – they are under stress to begin with.

My solution was to shim the gap between the UNSTRESSED front motor mount and the frame. THE ENTIRE INHERENT ELASTICITY OF THE MOUNTS IS NOW AVAILABLE TO ABSORB ENGINE MOTION. MY VIBRATION PROBLEM WAS GONE!

EDIT ---------

Try this site for photos: http://spotks.blogspot.com/

EDIT --------


Picture “A” shows the gap between the unstressed front motor mount and the frame of my bike – it is almost 0.2 inches. The solution is to shim this gap.

Picture “B” shows my test where I used washers as shims to test my theory. Result - excessive vibration is GONE. The bike is very smooth and the handlebars don’t jump around at idle.

Picture “C” shows the final result. I cut some brass shim stock to fit and used longer bolts to accommodate the shim’s thickness.

Picture “D” shows a scissors jack and block of wood I used to hold the engine up when I had the mounting bolts removed. I had my wife steady the bike and hold it level while I worked on the mount.

Picture “E” shows the shim stock I made and the bolts I used. The stock HD fasteners for the motor mounts are chrome plated, grade 8, socket head screws, 3/8 inch – 16 tpi – and 1 1/8 inches long. [CORRECTION: THE 2005 PARTS MANUAL LISTS THE BOLT LENGTH AS 1 1/8 INCH, THE MEASURED LENGTH IS 1 1/4 INCH] I obtained quality grade 8 bolts, (local caterpillar dealer) slightly longer than stock, to accommodate the shims and still retain the same purchase in the mount


EDIT ---------------

See "Thorns" great suggestion at post #30 to simplify this process.

EDIT --------------


Some Hints:
--- Don't force shims into the gap, you don't want to create a problem in the opposite direction.
- Have a Service Manual available for the alignment procedure.
- When initially measuring the frame to mount gap DO NOT LOOSEN THE REAR MOTOR MOUNT BOLTS. You want to determine the total mount to frame gap.
- After you shim the front mount, be sure to do the alignment procedure in the Service Manual as the rear mount now will need to be able to align itself.
- Be sure to keep the bike VERTICAL when you are working on these mounts. I attach a level to the front and to the rear brake disks to make sure the bike is level.
- My bike tracks straight, I did not need to mess with the alignment adjustment under the tank.
i tossed some washers in there some time ago. works as you say. good! the downside is i get that solid mount grumble at low r's in mid gears. not bad, just enuff to know what i did does have an effect. main issue is the bars no longer wobble around like a drunken whore at idle. it is a somewhat known fix. i am glad u stumbled upon it and shared the info. others should try it.
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Old 11-21-2012, 11:06 PM   #213 (permalink)
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Hacksawsgarage, Mine didn't much bar shake at idle but from reading this whole thread it looks like a lot of guys did. Mine just had heavy vibes between 60 and 70 most noticably in the seat. It's greatly diminished now and the vibes at other RPMs are less too. It's got a sweet spot at 65 now where it gets really smooth. Wish I could talk about RPMs but I got no tach. I really like this bike and consider myself very fortunate to have found this thread. Bruce
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Old 11-22-2012, 10:01 PM   #214 (permalink)
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Quote:
Originally Posted by Bprigge View Post
Hacksawsgarage, Mine didn't much bar shake at idle but from reading this whole thread it looks like a lot of guys did. Mine just had heavy vibes between 60 and 70 most noticably in the seat. It's greatly diminished now and the vibes at other RPMs are less too. It's got a sweet spot at 65 now where it gets really smooth. Wish I could talk about RPMs but I got no tach. I really like this bike and consider myself very fortunate to have found this thread. Bruce
Glad it helped.
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Old 06-20-2013, 03:58 PM   #215 (permalink)
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AWESOME! thanx...

Awesome results... thanks so much for figuring this BS out...
(laffs)

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Old 06-21-2013, 02:41 PM   #216 (permalink)
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I wondered about the vibration on mine... Now this makes sense!
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Old 10-02-2013, 12:41 PM   #217 (permalink)
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Some good info, but it isn't really anything new. Did read the whole thread and don't know if this has already been discussed. But, Norton rubber mounted their engines LONG before Harley ever figured it out. Back in the 70's I had to re-shim a 750 Norton I owned. Went to the Norton Dealer back then to buy a shim kit. It only goes to figure a Harley with a rubber mounted engine might need the same. Wonder if Harley even offers a kit or is aware of the problem and how to fix it.
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Old 10-02-2013, 02:50 PM   #218 (permalink)
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Quote:
Originally Posted by tenfive0 View Post
Some good info, but it isn't really anything new. Did read the whole thread and don't know if this has already been discussed. But, Norton rubber mounted their engines LONG before Harley ever figured it out. Back in the 70's I had to re-shim a 750 Norton I owned. Went to the Norton Dealer back then to buy a shim kit. It only goes to figure a Harley with a rubber mounted engine might need the same. Wonder if Harley even offers a kit or is aware of the problem and how to fix it.
I don't think it would be in the best interest of HD to offer a shim kit. That would be admitting there might be a problem and leave the dealer network unable to use the excuse that 'It's a Harley' when the motor is vibrating out of the frame with a real life vibration causing issue.
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Old 10-29-2013, 02:16 AM   #219 (permalink)
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I see a few post where it stated going 65 mph the bike smooves completely out. Since you don't have a tach, what gear are you in at 65 mph?
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Old 10-29-2013, 06:48 AM   #220 (permalink)
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I see a few post where it stated going 65 mph the bike smooves completely out. Since you don't have a tach, what gear are you in at 65 mph?
Mine starts smoothing out at 65 in 5th (2005 Dyna) and stays pretty smooth up to about 85. Then it will start vibrating again.
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Old 10-31-2013, 10:18 AM   #221 (permalink)
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Talking It worked for me!!! 04 FXD

My first FXD and I was to the point of thinking about buying another bike! I shimmed the top bolt with 2 1/8" washers and the bottom with 1 1/8" washer and my vibrations are gone!!! Thanks!!!
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Old 10-31-2013, 06:57 PM   #222 (permalink)
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Quote:
Originally Posted by scmuniz View Post
My first FXD and I was to the point of thinking about buying another bike! I shimmed the top bolt with 2 1/8" washers and the bottom with 1 1/8" washer and my vibrations are gone!!! Thanks!!!
Glad it worked well for you.
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Old 11-03-2013, 01:29 AM   #223 (permalink)
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Just to clarify, this is for the front motor mount only correct?
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Old 11-03-2013, 08:26 PM   #224 (permalink)
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Quote:
Originally Posted by TacoBellMan View Post
Just to clarify, this is for the front motor mount only correct?
Yes.

See "Hints" at the bottom of the original post. AFTER doing the shims, you will want to do the Alignment Procedure as described in the Service Manual.
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Old 11-07-2013, 02:55 PM   #225 (permalink)
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Quote:
Originally Posted by Bprigge View Post
I did my new to me 96 all stock Super Glide with 34K miles on it. I put 4 1/16th shims in last week and got a very noticable reduction in vibes. This was with a new front motor mount. The top bolt hole in the original front mount would only take about 5 pounds of torque do to stripped threads so I replaced the mount. When I shimed it last week it looked like there might be room for 1 more 1/16 shim so tonight I got back out there and put in 1 more shim for a total of 5/16" . This made a noticable difference too. The bike is now MUCH smoother then it was through the RPM range (no tach) I still get a seat buzz between 60 and 70 in top gear, will probably try an Air Hawk to see if that helps with the seat buzz.

Thanks 84FXRP for all your efforts on this. Bruce
Good to know the PO took good care of my bike. Thanks Bruce.
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