Some Basic Questions.....Horrendous Vibration
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Joined: Oct 2015
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From: Ft.Worth, Texas
Some Basic Questions.....Horrendous Vibration
Ive never done any engine work on a motorcycle to speak of and have been chasing a nasty vibration in my bike for awhile. It comes in at around 30mph and goes away at 70. The best way I can describe it is the way my Mercedes felt when the hydrolic motor mounts collapsed . It feels like the engine is sitting directly on the frame or, possibly a cracked frame. The vibration in the floor boards is horrendous . Its always had some vibration in the right floor board at highway speed but the left was always smooth. I have spent hours on my back with the bike in the air and cant find anywhere that the engine or exhaust is touching the frame. I cant find anything broken or worn. The front engine mount appears OK. I dont see any cracks. The vibration is definitely engine RPM related. I know these engines vibrate due to their design but, I dont think it should be felt this much throughout the whole bike. Now, to get to my questions. Remember, Ive never pulled a harley engine. besides the front motor mount and top engine mount, what else holds the engine in the frame?
Road Captain
Joined: Jun 2010
Posts: 533
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From: Fredericksburg, VA
I have only ridden an '80 FLT and a Twincam Ultra, as far as rubber mounted baggers. Even my shovel (FLT) was really smooth.... For a Harley. They both still shook.
The engine is connected to the transmission through a solid mount, and the transmission is tied into the swing arm bolt, right? I can't honestly say, I've looked at the underside of an Evo dresser. I'm trying to remember how my Evo Superglide was connected, but it's been a long time.... It doesn't necessarily have to be rubbing the frame, but, if either of the mounts is worn or misaligned/maladjusted, it will shake the whole bike. Isn't there something in the Service Manual about the engine mounts?
The engine is connected to the transmission through a solid mount, and the transmission is tied into the swing arm bolt, right? I can't honestly say, I've looked at the underside of an Evo dresser. I'm trying to remember how my Evo Superglide was connected, but it's been a long time.... It doesn't necessarily have to be rubbing the frame, but, if either of the mounts is worn or misaligned/maladjusted, it will shake the whole bike. Isn't there something in the Service Manual about the engine mounts?
Club Member
Joined: Apr 2011
Posts: 5,776
Likes: 7,811
From: SE Louisiana
Try loosening the center bolt on the front motor mount,
loosen the nut just enough to be able to turn the bolt with a wrench.
I double nutted mine,
learned that from a Glide Pro video,
I use their front mount also.
loosen the nut just enough to be able to turn the bolt with a wrench.
I double nutted mine,
learned that from a Glide Pro video,
I use their front mount also.
Outstanding HDF Member
Joined: Nov 2013
Posts: 2,358
Likes: 34
Been down this road. I would encourage you to do little until you get one of the guys in TX to swap rides with you so you get a good comparison and you of another Evo. I found tons of stuff wrong on mine chasing vibration but never cured it. It does run 1000 times better now though! I can't believe how many things I found wrong but like I said, nothing cured what I was looking to resolve.
Stellar HDF Member
Joined: Aug 2012
Posts: 2,664
Likes: 184
From: Indiana, USA
Not sure if you have what yo need but my $0.02
Vibration in a rubber mounted Evo is from mis-alignment in the rubber mount system. Your '89 is old enough the front rubber is most liekely squished or deteriorated. Basically the motor bounces on the front rubber as it pivots on the swingarm pivot shaft. Another common problem is the rubbers back at the swingarm under the football shaped plates with the chrome covers hiding the swingarm pivot shaft. If you don't have 1 get a good H-D Manual. After changing the (20 rubbrs in the rear and the 1 in the front align per the manual.
Basically, get it upright on a lift, place (2) weights in front of and outside each side of the front tire, (I use car jackstands). Tie string line to the top of a stand, go back around the rear tire and up to the other stand and tie it off. make the string line as high as possible on the front and rear tires. With the string just touching the front of the rear tire on both sides, the front wheel at rest straight should be centered in between the stringlines. Adjusting the front motor mount heim joint will correct misalignment. There is also a heim jointunder the tank to the heads. Get a manual before you decide to make any adjustments on the upper heim joint ASM
Vibration in a rubber mounted Evo is from mis-alignment in the rubber mount system. Your '89 is old enough the front rubber is most liekely squished or deteriorated. Basically the motor bounces on the front rubber as it pivots on the swingarm pivot shaft. Another common problem is the rubbers back at the swingarm under the football shaped plates with the chrome covers hiding the swingarm pivot shaft. If you don't have 1 get a good H-D Manual. After changing the (20 rubbrs in the rear and the 1 in the front align per the manual.
Basically, get it upright on a lift, place (2) weights in front of and outside each side of the front tire, (I use car jackstands). Tie string line to the top of a stand, go back around the rear tire and up to the other stand and tie it off. make the string line as high as possible on the front and rear tires. With the string just touching the front of the rear tire on both sides, the front wheel at rest straight should be centered in between the stringlines. Adjusting the front motor mount heim joint will correct misalignment. There is also a heim jointunder the tank to the heads. Get a manual before you decide to make any adjustments on the upper heim joint ASM
Stellar HDF Member
Joined: Aug 2012
Posts: 2,664
Likes: 184
From: Indiana, USA
But 1st!
Make sure the rear tire is properly aligned in the swingarm. The proper wat to do this is pop the chrome covers off the pivot shaft. You can bend a wire coat hanger to a long L and sticking the short end into the pivot shaft center hole, mark the center hole of the wheel axle on the long side. Take L Gage to other side and insert into pivot shaft to confirm axle is square in swingarm relative to swingarm pivot shaft
Make sure the rear tire is properly aligned in the swingarm. The proper wat to do this is pop the chrome covers off the pivot shaft. You can bend a wire coat hanger to a long L and sticking the short end into the pivot shaft center hole, mark the center hole of the wheel axle on the long side. Take L Gage to other side and insert into pivot shaft to confirm axle is square in swingarm relative to swingarm pivot shaft
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Outstanding HDF Member
Joined: Nov 2013
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On the dyna you need levels or angle finders to align the mounts. You don't need it for the other models?
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Joined: Oct 2015
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From: Ft.Worth, Texas
I suppose Im going to have to remove it completely to check it. It loos fine and is soft. I pried up on it with a pry bar and it seems OK.
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Joined: Oct 2015
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From: Ft.Worth, Texas
But 1st!
Make sure the rear tire is properly aligned in the swingarm. The proper wat to do this is pop the chrome covers off the pivot shaft. You can bend a wire coat hanger to a long L and sticking the short end into the pivot shaft center hole, mark the center hole of the wheel axle on the long side. Take L Gage to other side and insert into pivot shaft to confirm axle is square in swingarm relative to swingarm pivot shaft
Make sure the rear tire is properly aligned in the swingarm. The proper wat to do this is pop the chrome covers off the pivot shaft. You can bend a wire coat hanger to a long L and sticking the short end into the pivot shaft center hole, mark the center hole of the wheel axle on the long side. Take L Gage to other side and insert into pivot shaft to confirm axle is square in swingarm relative to swingarm pivot shaft