Engine mounts, yes again I hear you say.
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Joined: May 2009
Posts: 52
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From: Boston, England.
Engine mounts, yes again I hear you say.
2009 fxdc. 15000 miles. Front engine mount had had enough, rubber on front mount tight and sending vibes back into frame, could feel it in deceleration at around 2500rpm. So replaced front and rear mounts using lifts and jack as per usual to support engine, ran bike for 30 seconds with bolts loose, tightened everything up. Did the shimming on front mount as gap not big enough, now 0.40 as in manual.
I'm still get vibes at around the same revs, any ideas where I wanna be next, I've not done anything with stabilizer link on the top???
Thanks Paul.
I'm still get vibes at around the same revs, any ideas where I wanna be next, I've not done anything with stabilizer link on the top???
Thanks Paul.
Tourer
Joined: Feb 2017
Posts: 361
Likes: 56
From: Lancaster, CA.
I got a very similar vibration in my 2003 WG that would come and go. I finally traced it to low oil in the pan. I was new to Harleys, and this one used a bit of oil. When I checked it, no oil showed on the stick. My guess the vibe was the oil pump sucking air. Filled oil to the proper level and never got the vibration again. Best of all, my engine survived my stupidity.
Road Master
Joined: Aug 2008
Posts: 1,246
Likes: 251
From: Belle River Ontario
Power train alignment is crucial if you want the best handling and vibration free ride...you also have to understand how these bikes are designed and why using anything other then stock for your front mount...
There are two distinct halves to a Dyna: The front wheel, fork, and frame are one assembly. The rear wheel, swingarm, engine and transmission are a completely separate assembly. The two assemblies are connected to each other purely by the two rubber engine mounts, one in the front of the engine, the other on the back of the transmission. The top link is really just a stabilizer/locater for alignment purposes, and isn't really a structural link between the two halves. Any and all movement incurred by the engine is directly carried through the transmission to the swingarm and the rear wheel. If the engine vibrates in the longitudinal chassis plane, this isn't much of an issue. If it vibrates left to right, the swingarm and rear wheel move left to right. If the engine swings like a pendulum from the top link, the rear tire actually rolls onto it's sidewalls a little bit, back and forth. The purpose of all the different aftermarket stabilizers is to limit lateral engine movement, while allowing enough longitudinal movement to keep unwanted vibration in check. This architecture explains why a Dyna is much more sensitive to all chassis adjustments/issues than some bikes are... Air pressure, wheel bearings, steering bearings, swingarm bearings, and particularly drivetrain alignment... That's why the same outcome can be difficult to diagnose from bike to bike.
The good news is that when properly setup, a Dyna chassis is actually a very good handling platform.
There are two distinct halves to a Dyna: The front wheel, fork, and frame are one assembly. The rear wheel, swingarm, engine and transmission are a completely separate assembly. The two assemblies are connected to each other purely by the two rubber engine mounts, one in the front of the engine, the other on the back of the transmission. The top link is really just a stabilizer/locater for alignment purposes, and isn't really a structural link between the two halves. Any and all movement incurred by the engine is directly carried through the transmission to the swingarm and the rear wheel. If the engine vibrates in the longitudinal chassis plane, this isn't much of an issue. If it vibrates left to right, the swingarm and rear wheel move left to right. If the engine swings like a pendulum from the top link, the rear tire actually rolls onto it's sidewalls a little bit, back and forth. The purpose of all the different aftermarket stabilizers is to limit lateral engine movement, while allowing enough longitudinal movement to keep unwanted vibration in check. This architecture explains why a Dyna is much more sensitive to all chassis adjustments/issues than some bikes are... Air pressure, wheel bearings, steering bearings, swingarm bearings, and particularly drivetrain alignment... That's why the same outcome can be difficult to diagnose from bike to bike.
The good news is that when properly setup, a Dyna chassis is actually a very good handling platform.
Cruiser
Joined: Jul 2011
Posts: 169
Likes: 13
From: Bay Area, CA
that above is helpful - so ideally what is the best setup for a late model dyna, stock front and rear mounts + a stabilizer?
Extreme HDF Member
Joined: Jun 2014
Posts: 11,448
Likes: 2,299
From: NW Ohio
The Vibratechnics Predator mount is a popular alternative that tries to be a magic bullet but many find it less ideal that stock for damping.
OEM mounts plus stabilizers, such as Sputhe, seem to be the best overall solution for performance and NVH (Noise, Vibration, Harshness) but the large(ish) front stabilizers can be an issue for some setups.
A very popular combination is a Predator front, OE rear mount, and Sputhe rear stabilizer. However many (including myself) report a vibration around 2200 RPM. The clean appearance and excellent handling outweigh that for most of us.
There is a new mount from Kinetic Structures that looks interesting but owner reports are very scarce right now.
Depends on your budget and requirements.
HDF Community Team
Joined: Aug 2018
Posts: 3,070
Likes: 1,229
From: New Hampsha
My first Harley and my impression was "I didn't think it would vibrate this bad..."
Over the winter I put the Predator, a new rear OEM mount and rear Sputhe stabilizer. My subjective opinion: it is much better. Handling is much more precise, too.
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Joined: May 2009
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From: Boston, England.
I think for starters im going to go with my stock mounts and have another go but this time do a full alignment with the top stabilizer link, just not sure on the process. Do i want to be loosening the mounts again and run the motor for a short time whilst rear wheel of the ground and bike level before i touch the stabilizer link or do i just go with alignment first.
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Tourer
Joined: Oct 2017
Posts: 300
Likes: 45
From: Calgary
Reading this made me think of a related question I have.
I just replaced both front and rear motor mounts with OEM mounts. Vibrations didn't really change, maybe in low rpm settings but not noticable when I'm actually riding. Gonna shim it anyway because I noticed a space in the front when I was changing them.
With the new mounts my handling definitely improved. I went on a trip over the weekend through the rockies into BC (Canada) and got to ride some super fun twisty roads. I noticed that in the real twisty bits where I'm constantly shifting my *** from one side of the seat to the other to really lean into corners that for the moment while my weight was more on my pegs I would get a bit of a wobble. Nothing major and as soon as I sat back down it went away completely. Am I right to assume a stabilizer would help with that?
I just replaced both front and rear motor mounts with OEM mounts. Vibrations didn't really change, maybe in low rpm settings but not noticable when I'm actually riding. Gonna shim it anyway because I noticed a space in the front when I was changing them.
With the new mounts my handling definitely improved. I went on a trip over the weekend through the rockies into BC (Canada) and got to ride some super fun twisty roads. I noticed that in the real twisty bits where I'm constantly shifting my *** from one side of the seat to the other to really lean into corners that for the moment while my weight was more on my pegs I would get a bit of a wobble. Nothing major and as soon as I sat back down it went away completely. Am I right to assume a stabilizer would help with that?
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Outstanding HDF Member
Joined: Mar 2015
Posts: 2,840
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From: Philly Suburbs
I certainly won't claim this to be the "best" or "only" way to do this, but you may find my process helpful. Everything in this thread may not apply to you, but it'll give you the general idea: https://www.hdforums.com/forum/dyna-...top-mount.html
I'll also add that my goal was always handling first, vibration control second. Your preferences may be different!
I'll also add that my goal was always handling first, vibration control second. Your preferences may be different!
Last edited by F86; Aug 30, 2019 at 03:44 PM.
Cruiser
Joined: Jul 2011
Posts: 169
Likes: 13
From: Bay Area, CA
Probably, yes. The stock front mount is particularly susceptible to failure from heat, fatigue, and oil contamination but seems to be best current solution for proper vibration damping. It is somewhat less ideal for controlling lateral motion.
The Vibratechnics Predator mount is a popular alternative that tries to be a magic bullet but many find it less ideal that stock for damping.
OEM mounts plus stabilizers, such as Sputhe, seem to be the best overall solution for performance and NVH (Noise, Vibration, Harshness) but the large(ish) front stabilizers can be an issue for some setups.
A very popular combination is a Predator front, OE rear mount, and Sputhe rear stabilizer. However many (including myself) report a vibration around 2200 RPM. The clean appearance and excellent handling outweigh that for most of us.
There is a new mount from Kinetic Structures that looks interesting but owner reports are very scarce right now.
Depends on your budget and requirements.
The Vibratechnics Predator mount is a popular alternative that tries to be a magic bullet but many find it less ideal that stock for damping.
OEM mounts plus stabilizers, such as Sputhe, seem to be the best overall solution for performance and NVH (Noise, Vibration, Harshness) but the large(ish) front stabilizers can be an issue for some setups.
A very popular combination is a Predator front, OE rear mount, and Sputhe rear stabilizer. However many (including myself) report a vibration around 2200 RPM. The clean appearance and excellent handling outweigh that for most of us.
There is a new mount from Kinetic Structures that looks interesting but owner reports are very scarce right now.
Depends on your budget and requirements.