New member here! I have a 2012 Ultra Limited. It have just under 29,000 miles on it. I bought it new so all the miles are mine. In the last month it has started with a vibration while riding an almost any speed. I took it to the dealership and they could not find anything wrong. They suggested replacing the back tire. So I had the tire replaced and also did the prescribed 30,000 mile service. A little early but since I did not do a 20,000 mile one thought I should. $1034. later they said it was done and I took it home. The vibrations are still there. I had already replaced the plugs and air filter so I know they are good. On the way home I decided to engage the clutch and turn off the engine at about 40mph and sure enough the vibrations stopped. This seems to indicate to me that it's something in the engine. Has anyone else had this issue and if so what was the solution (other than trading in the bike)?

 

Check you motor mount bolts. My friends Road-King front motor mount nut came loose and fell off. He was starting the bike and I saw the motor rock all the way to the front frame. Only took a few minutes to see nut was missing.

Have someone start motor and watch it. Also rev it up to about 2000 in gear. You should fill that idle rock smooth out.

Does the front tire look good? Be sure you are spinbalanceing tires with fixed weights. No bead damping BS

 

get a real tech to determine where the vibration is coming from. could be wheel bearings, motor mount, head adjustment pipes, etc. A good tech will figure it out.
dont ride it with strange vibs

 

Check the motor mounts. Is it making any clunking sounds when you hit the gas?

 

Thanks Ripsaw: I have it scheduled to go back on Monday and that's what I told the service writer to do. The motor mounts were my first thought also. I just took it for a ride and you can feel a lot of vibration if you reach back and feel the bags. I tried shutting it down again doing about 40mph and coasting and the vibrations again stopped. Tried reving it up in the driveway and vibrations continue. The new rear tire has the fixed weights I checked them out, front tire looks real good with no cupping. Running 40lbs. in rear and 38 in front as per Harley specs. I switched out the plugs again today and could see no difference. I have been using NKG Iridium for the past 4 years and they work great but Harley says I should only run with Harley plugs so I put them back in and saw no difference so I put the NKG's back in. Also I use StarTron gas treatment about 4 times a year in the fuel tank so I assume the injector jets are clean.

 

Cut the injector or any other additives out. Plan mid-grade or premium fuel. 10% ethanol no problem. Ethanol is good since it cleans up any trace of water in tank. Use Harley's plug, not NKG unless Harley recommend them in service manual.. Plugs easily go 20-50K but just change the what owners manual says. Harley's system use the resistance of the plug to control ping with timing. Even look alike plugs have more resistance in them. They only work if you drive easy and do not WOT load it up. That is why mid-grade or even regular will work if you drive super easy or on flatland like I do. All that gas treatment will destroy the pre-sock in the fuel tank and cause all kinds of problems.
If it was missing, it would tell you by throwing a code. It know when a plug is not firing. I have see an engine problem with a shake that indeed was a bad injector. It actually took the dealer a while to figure it out. That is truly rare.
Keep in mind, these heavy wall tires actually run pretty rough. Would not be reaching back to the bags for vibration think it was motor. I would attach a stiff rod to motor and see if it truly is motor. Don't be a cash-cow to a service center. They will love you for it however.

Get one of your riders in your group to ride it and ride along to watch it.

 

No unusual noises. Besides the vibrations that make my teeth chatter and hands starting to go numb I find nothing else unusual.

 

I called my old service rep. in PA. and he said the same things about the plugs so I guess I'll put them back in before taking it back. I do only run 92 or 93 octane. I guess the fuel additive was an old habit from Pennsylvania when it sat for the winter so I just continued using it here in Florida although not as much as the bike never sits more than a week at a time. If they don't find the problem this time I will find a good local indi.

 

I retired 5 years ago. I never put up the bike since there is always a few days even if the bike sits months. However, I quit riding last year before Nov since we were traveling. Just got back last week.

First ride today and the bike started up fine and I even failed to fill tank when I parked it last year. Did take few more turns then normal. All we have had around er is 10% for longs as I can remember. I have worked on this stuff for 46 years and truly see no need for it especially in modern FI stuff since that does not dry up like vented carbs.

I have pulled tanks with the screes gone on petcocks and the sock gone on FI bikes and it's always on the once that people throw additives in there. However, they may have thrown too much. Not sure about that.

 

OP good luck with that and keep us posted as to the cause.

Probably something simple like a motor mount as mentioned.

Just stinks the dealer has you throw money at it not really knowing the cause and then let's you pick it up when it is not actually fixed. Hope you needed a new rear tire!

Good luck