Ok so I take my bike in to have the wheels powder coated black as well as have the front sprocket changed from a 16T back to stock. When the bike is all done I go pick it up and take the long way home because it's been a few weeks. All is well until I come up to about 95 mph on a straight and I notice what feels to me like the front tire out of balance. Call up the shop and inform them of my findings, and they said they'd like to rebalance the tire. Bring it in to have that done and it doesn't fix the issue.

Next he wants to try the silica BB's in the front and rear as well as go over the bike one more time to check for anything obvious. We do this and it still vibrates starting at 95 mph and up. At this point I'm thinking that maybe some powder coat got behind the rotors causing some run out so I break out my dial indicator and commence to checking things out. Front rotors had .009-.010" run out and the rear had a staggering .023". I think to myself, this has to be it so I bring the wheels back to the guy to have the rotors removed and the mounting surface checked for excess paint. While he had them he rebalanced them with the cush drive installed just to try something different. I reinstall and check runout once more, and to my surprise the rear now had .002" and the front was now .007" on both sides (spec is .011" iirc).

This made no change in the issue whatsoever so im starting to think that maybe the tire is at fault here. I mean its probably within 1000 miles of being at the service limit, so just last week I have a new front Michelin PR4 installed and as you can guess... no change. The rear is a Dunlop Q3 with several thousand miles left in it. The wheels do no appear bent just by spinning them on the stand, and the bike itself has 10,578 miles on it.

I've done as much online research as I can and can find nothing on this exact issue. I would like to add that the vibration doesn't seem to get more "heavy" with added speed, only increasingly frequent. I actually brought the bike up to 175 after the tire change to see what it would do, and the bike was stable as always just vibrating like a mfer.

Someone dropped one of your rims?

Runout would explain to my mind why it doesn't get worse at speed. If you lived near me you would be borrowing my rums to see if that made it go away. Then one at a time to be dead certain which one it was.

If someone has a decent balancer maybe mount them and spin them on that?

I just don't know at this point. I do know that he had to send the wheels out to be blasted before powder coating so its possible something happened there. I'm about to pull my hair out.

Hmmm could be a loss of suspension control. Have you done any suspension work or changes since the last time you didn't have any issues?

Back tire's pretty old, it's at least slightly suspect at this point.

Only other thing I can think of is roadway.

* Last updated by: VicThing on 6/13/2016 @ 5:04 PM *

No suspension changes have been made by me nor requested. The rear Q3 while worn a bit has only been on the bike 10 months. It does this vibration on any road, so I know that's not the case. Bike was butter smooth before having the wheels powder coated, and front sprocket changed back to stock.

* Last updated by: Nastynotch on 6/13/2016 @ 5:10 PM *

So if I read this correctly, you remounted teh used tires after powdercoating? IF so I would think the problem could well be the rear tire, especially since you mention it is worn.

Can you tell by laying your hand on the fork and tehn somewhere on the rear of the bike ( during vibrating) where the vibs are strongest?

* Last updated by: chrly on 6/13/2016 @ 6:34 PM *

They had to remove the bearings to powder coat, maybe they screwed up the new bearing install or maybe forgot to reinstall the spacer in between the bearings.

* Last updated by: wfozx14 on 6/13/2016 @ 7:44 PM *

Have your wheel/tire combo statically balanced by a different shop.

Maybe your regular guys are using a fooked dynamic balancer?

Possibly damaged bearings removing and reinstalling?

It could be the rims. But if they've been balanced, they should be balanced you know? At most the powdercoating added maybe a 3-4 ozs of weight to the rims. Frankly can't see anything happened to it that would make it impossible to balance.

I'd either check the bearings or wait until you replace the tires.

Also what Hagrid said. Shit I mount and balance my own tires and haven't had one balance issue using the hand balance method.

* Last updated by: VicThing on 6/13/2016 @ 8:02 PM *

First off, thank you for all the input fellas. I'm starting to suspect the bearings as well here. I know I told him to inspect them and replace if needed, but he told me they looked great so they went back in. Even though I'll be replacing the rear tire here pretty soon, I just don't think it's the culprit here. Also something I forgot to add is that when the bike is cold, the vibration is not near as noticeable as when the bike has been ridden for say 20+ miles. So yes it's heat dependant to a certain degree. I guess I can order new bearings, I just hate throwing money at an issue until I know for certain. That method never has paid off in the past.

Shit I mount and balance my own tires and haven't had one balance issue using the hand balance method.

Everything worked fine on the bike before but it's been a while since you used that sprocket. Maybe it has to reestablish a new pattern with the old chain. The chain takes a long enough time to make one rotation. I would expect it could cause a noticeable oscillation if something was out of whack.

* Last updated by: Rook on 6/14/2016 @ 7:11 AM *

Vibration/noise under floorboard GM Bulletin:
When transfer cases are rebuilt, time the hyvo chain to the gears.

Hub's Bulletin Factor Apply:
So since about 1989 I've timed my rear sprocket to my link. That's now 3 tire changes and the link to sprocket tooth wind up back in the same tooth to link position = Smooth Running w/out any new/induced vibration just throwing on link on a tooth and obtw.

The 16T was on the bike for approximately 1,000 miles. Couldn't stand the stutter so it had to go. Other than going back with all new parts, or just waiting on it to establish a new wear pattern, is there anything I can do about it? I have noticed the the chain rollers look like they're being worn on the outside alot more than the inside. The outside of the rollers look really shiny compared to the inside.

I'm thinking they were just sloppy with your reassembly.
Techs tend to love impacts and hate torque wrenches.

Have you made sure the rear wheel is aligned properly to the bike ... ie parallel to the line of travel?

I don't understand which part of your chain is looking shinier ... ? But if you mean the outside (left) ends of the rollers are shiny compared to the inside (right) ends, that sounds like the rear wheel could be not aligned, possibly aimed to the right (when sitting on the bike like normal). Doesn't seem like a shop would miss something that simple, but it's gotta be something.

If you don't know how to check that, it's a quick, easy visual: Count the number of lines on one side of the swingarm as to where the axle is sitting, and make sure the other side is sitting on the exact same number of lines. See the little tick marks on the swingarm above the axle:

* Last updated by: extrapolator on 6/14/2016 @ 3:04 PM *

Is the front sprocket side sensitive? Does it have a spacer on one side either separate or actually part of the sprocket? I have not had mine off so do not know but if the sprocket is backwards, even if the rear wheel is straight in the swingarm, the chain will show those marks.
Just looked at OEM parts.. THe front sprocket CAN be installed backwards.. Might want to check it, if rear wheel alignment is ok.

* Last updated by: chrly on 6/14/2016 @ 4:02 PM *

I honestly didn't know it was possible to remove and replace the same bearing. I think I would replace them. Most people pound them out, what tool/technic did the powdercoater use to remove them?

Same here. In fact, lost one of my stick on weights a while back and noticed no difference.

I kid you not, I have not even moved one wheel weight yet. I read that tires are very even today and that most imbalance is in the rim itself. My findings, with 2 sets of rims is this must be true. All I've done is follow the red>yellow dot and honestly have not had to move one wheel weight from where Kaw originally put them.

I'm sure the time will come but so far I haven't.

Thanks for all the input guys, I believe I've found the problem. Put the bike up on the stands and got the rear spinning at idle in first to do some inspecting. I immediately noticed the rear sprocket wobbling side to side (probably at least .200" run out). The chain was moving side to side just as bad. Just finished loading it up for drop off tomorrow. I would pull it off myself, but he also has a chip to fix in the powder coat on the front wheel. Stay tuned......

I immediately noticed the rear sprocket wobbling side to side (probably at least .200" run out). The chain was moving side to side just as bad.

How did the shop warped the rear sprocket? Maybe the rear sprocket hub spacer is not properly installed or one of the cush drive rubbers is missing??

I guess I'll have to see what he finds. I'm bringing him the bike complete.

Call first thing and hope the garbage is not picked up. No call from the shop, obtw? I'd look in Kofla's camera bag for the bumperettes. That, or the center collar is in the 25gal barrel or whatever they set the wheel on.

If they got the wheel with the sprocket, could have dropped the coupling out of it..or dropped the wheel on the sprocket. Sucks to think that could be it but that's what I'd be wondering. How'd the powder coat chip? If I were them, I'd be digging into my pocket for a new sprocket. That's why I'm such a horrible businessman. You fuck it, you fix it. There goes the profit on that one.

LOL reminds me of the last time I ever brought a wheel in for tire change. The guy dropped it on the floor on purpose right in front of me and the VP of the dealership. No harm to the wheel with rotor down but I was totally shocked he would do that to me because he was having a bad day at work. That was the last time I saw that guy at the shop.

They got the whole bike to do the powder coating, so I'm not sure what caused the sprocket issue. The chip was put there by the tech that installed my new tire last week. At this point I'm not mad, and feel like I owe it to them to make it right. We're all human,and shit happens.