Vibration at 2000 RPM

[CongaJon]

2004 1500 FI, PCIII with dyno tune from Hulten Motorsports. Thunder air kit and V&H pipes. Runs beautifully, except within about 150 RPMs either side of 2K. Any gear, any speed including on the stand. I just did the horn cover key relocation and it shakes and rattles violently at that range! Keeps me in a pretty jumpy 2nd in town.

Last winter I replaced the driveshaft (tight U joint) with a used one (loose U joint). The bike was new to me that fall, so I didn't get much time on it, but I really don't think it was doing that before I tore into it. I had originally replaced the U joint on the original shaft, but installed the used one I had purchased after feeling the vibration. Nothing seemed sketchy doing the install (s). I lubed everything and torqued to spec. Tonight I changed the oil, redid the plug wire ends and installed iridium plugs.

I don't have enough knowledge of drive trains to know what is turning in neutral, sadly. Perhaps it can't be related to the driveshaft. Whatever it is, it happens every time. Nothing intermittent about it!

My last battery lasted 50 weeks. When I started it tonight it acted briefly as though the new battery was down. Quickly caught and spun strongly. It has done this occasionally in the past. I read the posts about the ground gang melting, but couldn't find that on my bike. Does anyone know if the 1500 has 'em?

Sorry for the length, but I know there are some sharp men and woman on here that might pick up on some small detail.

Thanks for any insight you may be able to offer. Oh, I recently questioned whether I should replace a rather squared-off rear tire or wait. To a person, the suggestion was to replace. I did and nearly turned off the road on the first curve I hit. So that's how it's supposed to handle! It was so pronounced that I'm now a little wobbly on my stops. I was a Darksider!

Jon

[Snake Ranch]

Originally Posted by CongaJon

2004 1500 FI, PCIII with dyno tune from Hulten Motorsports. Thunder air kit and V&H pipes. Runs beautifully, except within about 150 RPMs either side of 2K. Any gear, any speed including on the stand. I just did the horn cover key relocation and it shakes and rattles violently at that range! Keeps me in a pretty jumpy 2nd in town.

Last winter I replaced the driveshaft (tight U joint) with a used one (loose U joint). The bike was new to me that fall, so I didn't get much time on it, but I really don't think it was doing that before I tore into it. I had originally replaced the U joint on the original shaft, but installed the used one I had purchased after feeling the vibration. Nothing seemed sketchy doing the install (s). I lubed everything and torqued to spec. Tonight I changed the oil, redid the plug wire ends and installed iridium plugs.

I don't have enough knowledge of drive trains to know what is turning in neutral, sadly. Perhaps it can't be related to the driveshaft. Whatever it is, it happens every time. Nothing intermittent about it!

My last battery lasted 50 weeks. When I started it tonight it acted briefly as though the new battery was down. Quickly caught and spun strongly. It has done this occasionally in the past. I read the posts about the ground gang melting, but couldn't find that on my bike. Does anyone know if the 1500 has 'em?

Sorry for the length, but I know there are some sharp men and woman on here that might pick up on some small detail.

Thanks for any insight you may be able to offer. Oh, I recently questioned whether I should replace a rather squared-off rear tire or wait. To a person, the suggestion was to replace. I did and nearly turned off the road on the first curve I hit. So that's how it's supposed to handle! It was so pronounced that I'm now a little wobbly on my stops. I was a Darksider!

Jon

When you say on the stand, is it in neutral and not moving? Both wheels are on the ground and not turning?

[CongaJon]

That is correct! Basically, it does it under any and all conditions.

[DragonLady58]

OK, all bikes are different. Around town, you can get by without hitting the 1800-2200rpm mark, not easy, but its doable. Yes, these big twins vibrate, but it shouldn't be uncomfortable or scarey unless your coming from a wing or a bimmer. The only things that can cause a bad vib in that range, without serious engine damage occurring swiftly is warn or loose engine mounts, which I've seen. Loose frame members (broken weld/motormount/cracked motormout attaching point). or bad wheel balance, either loosing a wheel weight, possibly even wheelbearing, cracked brake rotor, etc.
Also, the counterbalancer rubbers (engine) might be going away or are damaged.
Does this happen in any gear? Or a certain gear? At just certain engine rpms? Or a certain road speed?
Does it do it when its in neutral?

We really need more information....

If it does it regardless, even in neutral on sidestand, at a certain rpm, could only be engine bearings, counterbalancer problems, broken/loose mtr mount, maybe nuts are removed, vibrated loose, cracked frame....maybe even a loose flywheel....
Could be alot of diff. things....if happening going down the road.

To verify its something seriously wrong, wouldn't be a bad thing to get one of our members close by to listen and look to this vibration....might help locate it, might also help put you at ease if its nothing seriously wrong....

[Travelingnomad]

I am having roughly the same issue, I have been told the stock exhaust causes a vibration also around 1/4 throttle, I'm planning on switching​ exhaust soon and see if that helps , if not I'll be changing the counter balance dampeners to see if that is the issues. 08' 1600 nomad

[DragonLady58]

The Nomads vibrate, but not bad. yes, it shakes some but its not uncomfortable....
Damn, ya'll wanna experience shaking, ya'll should've rode my ole early 80s ElectraGlide 'Blackie'....
Now, she shook!!!!! Old S&S 96" wheel kit in her.....aaaaaahhhhh.....65-95 on the interstate....smooth as glass....she wasn't made for idling, she was made for hauling ass down the road....every 45,000 miles I was putting fresh rings in her....

Idling the 1500 down to get that Harley sound isn't good on the engine, oiling wise, also, beats the hell outta those counterbalancer rubbers, also. Will make them loose after awhile. Though theres usually no long term damage to them, my bike does lope up above the specified idle rpms....of course I'm not running stock cams either....

[MAS Tequila]

When is the last time you cleaned the throttle body?

How at the plugs, the plug wires?

Are the injectors clean?

There are so many different things that can cause a vibration it's not funny.

Try one of the Indians which were put together in NC.

Those things shook horribly.

[CongaJon]

The one thing you mentioned that I'm unsure of is the injectors. I'll run some cleaner through it. As I've never done this before, any recommendations as to what product to use?

I probably should replace the plug wires also, since all I did was cut back the ends at the plugs and screwed the boots back on.

[MAS Tequila]

SeaFoam

Add about 1/4 of a can to a full tank.

Remove the air cleaner, and with the bike running, put some SeaFoam in a Windex type sprayer and spray into the throttle body liberally until the bike almost dies.

Do this 10-15 times.

You will get a tremendous amount of white smoke, so make sure you have plenty of ventilation.