A few issues
I don't have a TT (although it gets such high praise here that I've been close), but my bikes builder advised against it for exactly the experience you are having - excessive vibration.
Hope you figure it out.
I had very much the same problem when I first installed the front TT, swore it was a bad front mount. Went through the trouble of pulling the mount completely out and nada, it was fine.
Then I tried spacing the front bracket away just by sticking some washers underneath it. That totally fixed the problem but to be sure it was OK, I took the attached shots (first three) and sent them back to American Cycle. They didn't like the fact that I put shims under the bracket. Told me to take them out.
Then I found a post on the V-Twin forum by 84FXRP that showed how to remedy similar issue by putting the shims between the frame and the bottom of the front mount, more attached pics.
Actually just tried to get everything into this first post, won't fit, so will post the fix I found in the next section, this guy deserves the credit so I'm going to try to put all his text and stuff in there too. I can't find the link to his post or would do that, but I did copy from there and pasted into a Word doc so I have all that.. anyway, next post.
Hope this helps, good luck.
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Last edited by Robottom; Oct 17, 2023 at 12:15 PM.
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 âBar Snakeâ, 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 Dynaâs, 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 â 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 â 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!
Picture "A" shows the gap between the unstressed front motor mount and the frame of my bike â 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.
NOTE: He had to use a jack below th eengine to get enough clearance to get the shims inserted. I did the same but made mine slightly thicker than he did to be sure I was buying clearance between the two pieces of the TT.
Picture "C" shows the final result. I cut some brass shim stock to fit and used longer bolts to accommodate the shimâs thickness.
Picture below 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 â 16 tpi â 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
Last edited by Robottom; Oct 17, 2023 at 12:15 PM.
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