I have a strange anomaly that happens right around 3000 rpms and I can't figure out what it is.

It's a sort of quick vibration spurt. I only feel it through the highway pegs on the crash bar. I don't feel it anywhere else on the bike; foot boards, handle bars and I've placed my hand on the frame and can't feel it. There are no unusual noises coming from the engine when it happens either.

It's kinda random and doesn't happen all the time and it is very short and may be one or two or a few right together and it only happens right around 3000 rpms and happens in every gear. It feels like a short vibration, like something came out of balance and quickly righted itself or like if you were to run over real tight rumble strips. If I drop below 3k rpms it doesn't do it and if I accelerate above 3k rpms it doesn't do it.

Is there anything in the engine or elsewhere on the bike that could display this type of action?

I've checked that the crash bars are secure but I gotta believe if it was something loose it would happen all the time not just at around the 3000 rpm mark.

It started after I changed my front tire about 2000 miles ago (I used dyna beads). But again I don't feel it through the handle bars only the highway pegs on the crash bar so I'm thinking this is only coincidence?

Thanks for any help in advance,

Robert

 

Could be the dyna beads sticking to whatever was used for lube during the tire install.

 

That's strange. I have the same phenomenon going on only through the pegs and it's right at 3K. I don't use Dynabeads and my bike is stock. At first I thought it was a plug misfire and I replaced the plugs...no change. Hopefully one of the geniuses around here can explain.

 

I have the same thing going on at 2800 RPM. Only feel it when feet are on cruise pegs and happens in any gear. 2010 Ultra Classic with 15000 miles. First notice it probably around 5000 miles but could have been happening since new. Just didn't notice it until later. Has never gotten better or worse since first noticing it.

 

My 03 RK does the same thing. I've just assumed it is a demon of rpm harmonics right around 28-2900 RMP. Most noticeable around 60-62 MPH and when kicked up 3-5 mph or lowered the same, the vibration goes away and it once again is a smooth cruiser. Looking for an answer but otherwise it runs great and has been a great bike (13K miles).

 

Okay, well at least I'm not crazy. Hopefully someone here can give us some idea of the cause.

 

Bumping this up for more visibility.

Here's a question, I still would like to know what is causing the issue but wonder if I used some type of rubber strip to mount the pegs on the bars I wonder if that may absorb the vibration and not transfer to the peg?

 

I've had the same issue on my 09 from the beginning. Harley replaced the engine mounts, checked the eng alignment as well as checking everything else possible. I have also replaced the compensator with an SE version.
I have been through multiple tires over time and the vibration is still there.
33,000 miles and no issues so I stopped worrying about it.

 

What you are describing is a frequency sensitive harmonic vibration. At the rpm you describe, the powertrain, chassis, and all the related parts are sensitive to whatever frequency that (likely the engine and drivetrain) is producing and creating a tuning fork affect that you can feel. Lower frequencies tend to be 'felt' where higher frequencies tend to be 'heard' I doubt that what you feel is of any concern, as it is merely the combination of bolted on parts reacting to a frequency vibration created by the motorcycle itself.

 

Well, I think I may have fixed this problem I hope. Was only able to get about 5 miles on it after the fix. I did two things but not sure which may have been the solution:

1. I replaced the rubber bushings on the rear exhaust hangers.

2. Since I was feeling the vibration through the highway pegs I figured I'd try and insulate them somehow. I picked up some of the thin foam sheets you can get at craft stores. I got the one that is sticky on one side. Cut out a piece to put on the inside of the clamps and then put the on the bars.

Hopefully, this is the fix for it. I'll verify tomorrow on a longer ride.