Weird isolated rpm vibration?
Tourer
Joined: Apr 2006
Posts: 358
Likes: 0
From: Northern VA
I also had a vibration at the same RPM's found out that the top bolt in the engine guard was broken. Drove me nuts to find too because it would happen in every gear at that speicific RPM range. Hope that is is something simple as the bolt to replace.
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Road Captain
Joined: Jul 2009
Posts: 578
Likes: 0
From: Tea, SD
Too busy to start with it this weekend. Mama and the kids took over. So I will check over and test this week.
Sturgis has all the dealers around here just swamped with bikes broken down.
LOL's
At least for now my bikes not there yet.
Sturgis has all the dealers around here just swamped with bikes broken down.
LOL's
At least for now my bikes not there yet.
Advanced
Joined: Jul 2006
Posts: 72
Likes: 0
From: Arkansas
Just picked up a low mileage 2005 FXDXI with excessive high freq. vibration in the same speed range [2800-3100 RPM].
Interesting, uh?
I think I see some damage to the front mount rubber isolator. Going to get some help checking the motor mounts as that is the most likely cause from what I've read.
Interesting, uh?
I think I see some damage to the front mount rubber isolator. Going to get some help checking the motor mounts as that is the most likely cause from what I've read.
Advanced
Joined: Jul 2006
Posts: 72
Likes: 0
From: Arkansas
Dealership said that the top motor mount was loose and that they performed the alignment where you loosen the motor mount bolts, run the engine, and then re torque the bolts.
The service tech thought they had improved it but after riding it today, I can't tell much difference -- still really buzzy 2800-3100 rpm. It's very smooth at 3400 and up so I'm keeping the engine wound up a little more than usual for cruising.
May try the front motor mount shimming trick next.
Love the bike, but it is the buzziest of the five TC88 based Harleys I've had.
The service tech thought they had improved it but after riding it today, I can't tell much difference -- still really buzzy 2800-3100 rpm. It's very smooth at 3400 and up so I'm keeping the engine wound up a little more than usual for cruising.
May try the front motor mount shimming trick next.
Love the bike, but it is the buzziest of the five TC88 based Harleys I've had.
Road Warrior
Joined: Nov 2007
Posts: 1,984
Likes: 7
Still something loose.
Check handle bars, risers, floorboards, exhaust bolts.
could be anything that can come loose.
If a solftail, there is a lower engine bolt behing the right floorboard mount. gotta take the thing off to get to it.
Pushrod adjustment can cause vibration if not correct.
Primary drive system and clutch if something out of adjustment.
Wheel balance and trueness can cause problems.
I have found when tuning the tune can cause engine vibration as the cilenders can be just too different, timing and VE and such.
Many things, but if it is a new thing, something is out of wack and it is maybe dangerous.
Check handle bars, risers, floorboards, exhaust bolts.
could be anything that can come loose.
If a solftail, there is a lower engine bolt behing the right floorboard mount. gotta take the thing off to get to it.
Pushrod adjustment can cause vibration if not correct.
Primary drive system and clutch if something out of adjustment.
Wheel balance and trueness can cause problems.
I have found when tuning the tune can cause engine vibration as the cilenders can be just too different, timing and VE and such.
Many things, but if it is a new thing, something is out of wack and it is maybe dangerous.
Last edited by Old Gunny; Aug 24, 2009 at 02:18 PM.
Advanced
Joined: Jul 2006
Posts: 72
Likes: 0
From: Arkansas
Thanks Gunny.
I bought the bike used so I don't know how long it's been doing this. I suspect it was doing it all along and the previous owner just thought it was normal as it really isn't that bad. If I hadn't owned several recent model TC88's, including two Dynas, I might not have noticed it.
The symptoms are very much like those reported by other Dyna owners -- down to the specific RPM range. and several have had success shimming the front motor mount.
I also suspect the tuning. It may have a flat spot in that RPM range.
If tightening some other bolts and trying the shim doesn't do anything, I may get the tuning looked at. It has SE II's on it and I was told it had the Stage 1 download. The bike was immaculate so I doubt the previous owner put the SE II's on and didn't
do the Stage I. It "feels" like Stage 1 bike.
I bought the bike used so I don't know how long it's been doing this. I suspect it was doing it all along and the previous owner just thought it was normal as it really isn't that bad. If I hadn't owned several recent model TC88's, including two Dynas, I might not have noticed it.
The symptoms are very much like those reported by other Dyna owners -- down to the specific RPM range. and several have had success shimming the front motor mount.
I also suspect the tuning. It may have a flat spot in that RPM range.
If tightening some other bolts and trying the shim doesn't do anything, I may get the tuning looked at. It has SE II's on it and I was told it had the Stage 1 download. The bike was immaculate so I doubt the previous owner put the SE II's on and didn't
do the Stage I. It "feels" like Stage 1 bike.
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Road Captain
Joined: Jul 2009
Posts: 578
Likes: 0
From: Tea, SD
Update
Two weeks ago tried taking the hw pegs off.
Vibration still there.
Took it to a shop and had the comp tested.
No it's not a motorcycle shop but one of the techs there works on bikes after hours.
I work there part time for mad money.
Tested at front 160.
Tested at rear 151.
Leak down test brought forth indications of a weak exhaust valve seal on the rear cylinder.
I am seriously now thinking of doing an after market big bore.
The main cause of the isolated vibration was the top motor mount.
It was shot.
So with that worn mount I am also thinking of getting the crank welded, pinned, and balanced.
Took it to the dealership to get the mount replaced for nothing.
Vibration still there.
Took it to a shop and had the comp tested.
No it's not a motorcycle shop but one of the techs there works on bikes after hours.
I work there part time for mad money.
Tested at front 160.
Tested at rear 151.
Leak down test brought forth indications of a weak exhaust valve seal on the rear cylinder.
I am seriously now thinking of doing an after market big bore.
The main cause of the isolated vibration was the top motor mount.
It was shot.
So with that worn mount I am also thinking of getting the crank welded, pinned, and balanced.
Took it to the dealership to get the mount replaced for nothing.
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