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I recently purchased a 2014 Street Glide SG with 2650 miles on it. The bike runs fine but after riding it while it seemed like vibration at speed and idle was excessive. I thought even though this bike has low mileage there may be an issue with the motor mounts. I decided to inspect them.
I started by removing the upper engine support bolt that attaches the support rod to the left frame downtube. When I removed it the top of the engine shifted to the left about 1/4 in. I don't thing this is normal. I followed the instructions in the service manual on how to remove the front motor mounts and inspected them. They appeared in like new condition I did not remove and inspect the rear motor mounts or inspect them.
I decided to relieve the side loading stress at the top of the engine and see if it makes any difference. Here are some pics of what I did.
This is how far off center the bolt was after being loosened. It looked like about 1/4 inch. It sprung over to this position after the last thread was loose.
I removed the whole bracker assembly.
I put it in my drillpress and drilled out the head mounting holes using a 1/2 inch drillbit.
I re-installed the mount with the head mounting bolts loose. I was able to install the arm support bolt easily by hand.
After tightening the bolts I started the engine. The handlebars seemed to vibrate less. With the engine running, I loosened the two cylinder head bracket mounting bolts. The handlebars came to a complete standstill. I retorqued those bolts with the engine running and the handlebars had minimal vibration. I would say about 75% less then when I started.
On the test drive it seemed to me to have less vibration at speed and a lot less vibration at redlights. It seemed to be more neutral going through corners with less understeer.
I think I made an improvement here but I still can't help to wonder why there was so much side loading at the top support bracker in the first place. Is that engineered into it and if so why. With that stress relieved at the top of the engine like that will that create some other sort of issue. I don't know and am not recommending to anyone to do this. I have been riding around with it like this for weeks now and I do enjoy the ride a lot more. Does anyone else's top mount have this same side loading? Any feedback would be appreciated.
The engine is rubber mounted, it will move to the left if you remove the link bolt while on the kick stand. If the bike is standing straight up and down when you remove the bolt there should be little to no movement. Hope that makes sense.
Great post, great work. Just want to say, the 14 and below bikes have almost always had that little left sided pull when you relieve the top motor mount (been said it's the weight of the primary etc), but if you really want to see it way worse, just pull one on a 2017. It will move over near an inch. This is with the bike straight up, not side stand.
I took some pictures (that I cannot find now) of the left front motor mount (on a 17) and it's center stud is already compressed downward nearly to the side wall. I showed this to a shop and they showed me 3 more just like it - apparently normal...
So... like you and based on what I thought was too much vibration transmitted into the frame/neck, thus handlebars, I bought an adjustable bottom engine link off a 90's Dyna.
I used it in place of the one size fits all top mount link on my 17 (which is just like yours). I adjusted so you could hand screw in the frame bolt, and bam... just like your's, less vibration.
Still running it that way today with no apparent issues in something like 15K miles and 1.5 years.
Thanks for the replies. This was all done with the bike held upright by my scissors jack and it does make sense to check this with the bike upright. I haven't checked my 18 Limited because it does have the same vibration issue. I am curious now though since IP's efforts reduced some vibs. Thanks again.
I noticed the bars on my 16 RGS vibrated a lot when stock. Once I changed them and switched out the rubber riser bushings for the poly ones, the bars dont vibrate near as much. It was a big improvement. Youd think that youd feel more by going to a more solid point of attachment but I saw the opposite happen. They still vibrate some when you take your hands off of the bars at idle, but at speed, I dont feel a thing.
Interesting post. I traded in my 13 RGU for a 16 RGU. Although I road the bike before purchasing, I didn't notice excess handlebar vibration. However, once I got the bike home and did a long ride I really noticed the difference. My 13 was smooth as silk, but the 16 was very objectionable. I tried balancing the tires to no avail. Then I re torqued everything that the engine touched. The torques were off quite a bit. That made a tremendous difference, but the vibration was still worse than my 13.
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Handlebar vibration
