This thread now has value only as a historic problem-identifying issue....

1999 Road King (Classic, if that matters) No engine modifications.

I'm feeling something strange here. Keep in mind, the vibration is felt ONLY in the left floor board. It happens when I'm engine braking in either 1st or 2nd gear, not so much in 3rd, and not at all in 4th or 5th. If I'm decelerating or coasting, if I hit a moderate bump or dip in the road, it feels as if the entire engine/transmission assembly is jumping up in the frame. So far, I've not noticed any vibration or clunk/thud when the bike is accelerating or under constant, steady power. I've inspected the mounts/stabilizers, and they seem to be fine. The frame does not appear to be cracked anywhere. I cannot wiggle the motor in the frame either on the floor or on the lift. I cannot wiggle the rear wheel, again, either in the air or on the ground.

This is really baffling to me. Any suggestions or, better yet, solutions from someone that's experienced this same thing before?

Thanking you all in advance!

 

Have you pulled your Primary cover,may be something loose behind it !!!

 

Wheel bearings or motor mounts. Possibly neck bearings. Wouldn't ride it till you find out though.

Mark

 

Yeah, I just closed up the primary. Everything is in order in there. Good thought, though! Thanks!

 

Not that either, as far as I can tell. As I said in the original post, the mounts were the first things I checked. The wheel bearings are solid, as is the neck bearing.

What is weird to me, is that the vibration can be felt ONLY in the left floor board. I would think, that if it were the wheels at fault, I'd feel it on both sides.

Any other ideas?

 

Had the same symptoms,only felt it in the left peg.When slowing by downshifting.Same thing on bumps.Couldnt figure it out till the rear motor mount finally fell apart.

 

I found it!!!

Turns out I was so fixated on the stabilizers, that I overlooked the forward main bolt. It is directly below the oil filter, and to the left & rear of the forward stabilizer link. I had tried to wiggle it a couple of days ago, before I tore into the primary, transmission & cam chest. It seems that when I went for a check ride after getting it all back together, the BROKEN BOLT had worked its way up about 1/4 inch. Well, I went & got a new grade-8 nut, bolt & lock washer, and everything's just dandy now.

Thanks for all the help and ideas, and I apologize for telling you that I had checked something, when, in fact, I had only glanced at it.

Now, if only the weather would cooperate....

 

Come on up to Salem HD and stop in, I'll buy you a cup of coffee. Glad you found the clunk.

Mark

 

Glad you were able to find the prob.
Some times it can be a real nightmare .