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Vibrations, shutter, passenger - what's it all mean?


Indy Dave

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I've hesitated to share my suspected driveline vibration, preferring to let the dealer have a shot unhindered by my second guessing. Diagnosing without riding isn't a science, especially when it comes to vibrations, ect.

 

For some time - meaning I had this issue with the last set of tires too - I have a subtle low speed vibration down low on low speed turns. Not every time (of course). One buddy last year dismissed it as being the larger gap on the tires, which I doubt - typically low speed does not have one leaned over a bunch.

 

A week ago Sat, I took the wife for a short ride and about a mile down the road, started to get a strong, unmistakable vibration. Previously when I'd ask her if she "felt that" [referring to the subtle vibration] she'd say - "felt what?" This time she could. Primarily on low speed turns - we were gently exploring an adjacent neighborhood. But also on braking. I nursed it home. SO - not constant, under braking and turns - may have done it in a straight line, if so, intermittently. I remember my concern was when I'd turn.

 

Setting was for 2 up. Wilburs shocks.

Rebuilt driveshaft 9 months ago (I had the subtle intermittent vibration prior to that)

Final Drive seems tight at 9-3 and 12-6.

No drive fluid leaking.

 

Dealer rode solo, found no issue. Says they've never heard of a FD failure without leaking first. I advised they needed to ride two up and the noise/vibration would be unmistakable and offer to bring in my top case to facilitate. I arrive and service manager says the Gen Mgr says insurance won't cover two up riding and that they have never had to do that to diagnose a problem. I counter that the bike is made for two up riding, etc and he agrees. But hands are tied. Assures me there is no problem and to just ride. Or -he added - it might be the driveshaft's spot welds. Hmm. Maybe, but I think I'd have felt that at my ankles. And it's the wife has been on the bike many times since the driveshaft without issue. But possible, maybe?

 

I tell him OK, I'll settle up :shake:

 

Then I see some bags of salt on a skid and ask why doesn't he put a bag in the top box and lash a couple of bags to the back seat? He agrees to try that, but hasn't yet due to weather and or time. I called him Friday and said he had till Wed to diagnose, then I was going to need to get the bike. I have a surgery coming up that means I need to do my Winter maintenance now - which included pulling the driveshaft to lube.

 

Any ideas from the collective wisdom? Is a final drive failure only possible after it starts leaking?! :dontknow:

 

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No I think the could fail without leaking also.

But you could also have a u-joint going out on the rebuilt drive shaft.

What brand tires and how many miles?

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I'm using PR3's, approx 3000 miles

 

Driveshaft still under warranty. :)

Edited by workin' them angels
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Morning Dave

 

I have seen a number of hexhead final drive bearing failures without any signs of gear oil leakage.

 

The number one failure item in the hexhead final drive is the crown bearing & that doesn't run in the gear oil (has it's own sealed chamber)

 

It sounds like you need to find a new dealer with an experienced service manager (your present dealer doesn't seem to have a clue)

 

Is your problem an actual VIBRATION or more of a growl without the shake of a vibration?

 

Can you feel it in the riders foot pegs or more in the seat & handlebars?

 

Your problem sounds somewhat like a crown bearing going out but those don't usually cause an actual vibration but more of a felt buzz or growl in the foot pegs.

 

In any case you need to find a dealer or technician that will spend more time checking your problem out than trying to talk their way out of doing anything.

 

Added: can you feel your "vibration" ONLY under engine power or can you reproduce it by coasting through the offending speed with the engine off & the clutch lever pulled in?

 

 

 

Edited by dirtrider
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Good Morning Dirtrider - Thanks as always for your insightful and helpful response.

 

My impression has been the subtle/intermittent has been foot pegs.

 

The two up was certainly a vibration with a shake (that wasn't limited to the pegs and is considerably more severe than the subtle vibration I'd catch from time to time), and with accompanying noise as well. The noise I don't remember as being 'clanky' - like the driveshaft hitting the housing for example. I didn't think to pull in the clutch or cut power. The noise is so obvious and repeatable (with 2 up) that I didn't analyze it as much as I now know I should have. :dopeslap:

 

I'll get the bike back tomorrow and Shawn and I will go for a short ride and I'll pull clutch and see, and pull clutch and cut engine. I'll report back.

 

My uninformed impression was crown bearing based on other threads - but I've tried not to push in that direction as I have zero experience.

Edited by workin' them angels
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Morning Dave

 

Do you get the very SAME noise & vibrations no matter the bike's lean (both left & right lean as well as different lean angles?

 

That might help us define what is going on from afar.

 

 

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Not sure if it is related or not, but there was an interesting article in MC News - actually a response to a reader's question about tires. The reader said that they experienced vibration with Pirelli's and said when they changed out the vibration went away. The question was along the lines of, are some tires better for some bikes than others. The answer was yes. The reader said once he swapped out the tires the vibration went away and said he had recently changed out tires again to Michelins and again it was gone.

 

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I was thinking along similar lines - vibration caused by front tire cupping. The tread blocks on the PR3's develop some interesting shapes, especially if they are run under 40 psi or so. But I'd expect the vibration to be present on all low speed corners, not just two-up. If it is the tire, it really is not a safety problem, it will still brake

and corner very well.

Edited by lkraus
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Sonor and lkraus - Thank you for taking a minute to help out. Another board member also has tires on his list of considerations. There may be something to this. My tendency has been to discount tires some in this instance because the slight/subtle vibration that is intermittent has transcended tire sets, a set of PR4's - which were cupped badly up front (and I felt the rear was sloppy as it wore - hence my switch back to PR3's), then a set of PR3's that I went through quickly last summer and now this set of PR3's.

 

 

Reconsidering tires yesterday (while trying to reproduce the vibration) the subtle vibration that's intermittent may in fact be a result of the Wilburs shocks. They are not as 'dampened' as the factory shock, by which I mean they transmit more road feel to the rider. I Believe this is a good thing, but it's unnerving at first as you suddenly feel all kinds of things you didn't use to. So it's possible - or likely even that subtle intermittent vibration is the shock transmitting feedback of the road surface or perhaps cupping tires. But that does not in any way explain the loud and jerky shudder we had last week.

 

UPDATE: I picked up the bike yesterday. Dealer said they put 100lbs of salt on back seat and rode and found nothing. While I'd considered a career in weight guessing at the caravel at one time, I've never even played one to TV (so what do I know?), but a 100 lbs is at least 50lbs short or probably more of my two up weight. The mechanic is a short slender guy.

 

Mrs WTA is out of town till tomorrow night, so I rode to my buddy's house and he hopped on the back. He's 6.4 and 80 - 100# more than Mrs WTA. The unavoidable loud/jerky vibration from last week was a no show. HOWEVER, we were able to hear and feel a vibration and our conclusions are:

 

1) I feel it more often then he did.

 

2) It happens more turning left or weaving left - almost always just off center or at the beginning of the lean. I could replicate the vibration right as well, but to the left was pretty repeatable. It also seemed at times to go from no vibration (straight up) to vibration as lean transitioned and then sharper lean perhaps vibration disappearing. The vibration didn't always disappear through the lean through.

 

3) Killing engine and clutch did not stop vibration. Clutch alone did not stop either.

 

4) Hard to attribute noise - may have been a scoring sound, but that seems like it could be brakes.

 

5) I could not invoke the alarming shudder/vibration and noise of last weekend. So I'll recruit Mrs WTA and repeat this Sat.

 

6) In regards to tire and shock road condition transmission to rider, that simply cannot account for the shudder that was repeatable with turns and braking when Mrs WTA was on the back.

 

7) Perhaps significant - the vibration I'm feeling through the seat. I'd thought earlier I was getting it from the pegs.

 

Lastly, my buddy is not very mechanical. Had I not pointed out the the vibration, he's not sure he would have noticed. Even allowing for 'knowing your own bike' and the shock - the elephant in the room is still the significant shudder we had last Saturday.

 

 

 

 

Edited by workin' them angels
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Afternoon Dave

 

With your 'new' noise appearing as you lean the bike but then go away the more that you lean it that sort of points to tire wear. (you might have some tire wear induced noise on top of your other noises/vibrations)-- Tire wear noise usually shows up first just off center in a mild lean. Front tire wear (cupping/feathering) can also usually be felt in the handle bars as you lean the bike in a mild turn (usually worse to the left as L/H side wear is usually worse than R/H wear.

 

As to feeling it in the seat more than foot pegs-- That can be tires, or drive shaft, or mechanical.

 

If you can get the noise/vibration consistently with a passenger on the back maybe try another short ride with the tire pressures let down to 22 psi. If that changes the noise/vibration then that points to a tire wear issue.

 

You might also ride the bike to warm the gear oils, then put on center stand, then lightly pry rear brake pads back a bit to remove contact from rear brake rotor.

 

Now slowly spin the rear wheel looking for bearing growl or disturbance.

 

Then put trans in 2nd gear, use a zip tie to hold clutch lever all the way pulled in, then again spin rear wheel looking for a change in turning resistance as you spin the wheel (this could point to drive shaft phasing or U joint issues.

 

 

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Dave,

When is it tire time? that would/could eliminate/narrow down.

The Wilbers.

Come with bike?

Or did you order?

If came with, prior owner size etc and did they order or acquire.

I ask because mine were set up for me, in ATGATT, with bag weight, and adjustable for when Beth was pillion.

We set up sag with her, etc, so I could just make a minor remote adjustment. They are solid.

They are rebuildable also.

Herman at wheels n wings did mine, and numerous others I know of.

Factory trained, very good work.

You need a ride to Florida, right?

Good luck.

Edited by tallman
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Thanks again for the input

 

Dr - I'll pursue you ideas and report back.

 

 

Tim: I had Herman (great guy) build the Wilbur's for me - with consideration to my weight and topbox for normal riding, but also with consideration of two up riding - with the understanding that Mrs WTA doesn't 'travel' by bike, only short rides. I'd need to look at miles, but just started year 3 of the Wilburs in Sept.

 

 

 

 

 

The alarming incident - which caused me to post - was that shudder and noise that was repeatable at the time and not subtle at all. It now seems to be on holiday :P:S:ohboy:

 

And YES, I do need a ride to Florida!

Edited by workin' them angels
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Dave, do you increase the preload on the rear shock when you add a passenger? If not, that could cause the balance to shift and may add some vibrations from the front wheel.

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The Mrs returned and I convinced her to putz around the neighborhood in temps cooler than she'd like - for the sake of posterity.

 

The aggressive shudder that we'd felt and heard before was again suffering from stage fright and couldn't be coaxed out of hiding.

 

We did get the rear vibration, repeatable at will, in both directions (left and right). We did learn one thing - the vibration doesn't present itself above 18 mph.

 

Back tot he garage, I lowered the tire pressures to 22 psi. As suspected by DR, this moved the vibration to mostly center riding - going straight down the road.

 

I put the bike on the center stand and turning the rear wheel forward, get a slight clunking sound - clutch in/out, and in 2nd gear, clutch in - same sound. Not present spinning backwards.

 

I recorded the clunking. And in color!

 

http://vid1130.photobucket.com/albums/m540/indycar89/bmwst/final%20drive%20wheel%20spin.mp4

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Yeah, there is a regular little thunk that I do not hear on my '06. My next best guess is a worn universal joint. I don't know if you can pull the boot back from the drive housing and see if the shaft is in the same position each time it thunks? If it is, the noise is a u-joint; if not it's the FD. Next, I'd probably drop the final drive to separate it from the drive shaft and see how they feel apart.

 

Edited by lkraus
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Morning Dave

 

That clunking noise root is difficult to tell as I can't see the tire rotation in relation to the clunking.

 

It sounds a bit like U joint clunk but with no real reference to tire rotation vs clunk I just can't tell. Can you do that tire spin test again with a chalk mark on the tire for reference & showing that reference as you spin the tire? Also do the same spin test as well as a slower constant spin (as constant as possible anyhow but "just" fast enough to hear the clunk)

 

Did you pry the rear brake pads back slightly before the spin test?

 

Some of the 1200RT's do have some normal noise in the drive shaft with bike on center stand as the wheel travel is at max & drive shaft angles are not as ridden.

 

On the tire pressure effecting the noise to center riding (center tire) that part point to tire wear just off center. Can you feel anything by lightly running your hand around the tire tread on-center then just off-center.

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Thanks guys for your feedback. I'll do some additional investigations tomorrow and report back.

 

DR: I did pry the rear pads back. After spinning the wheel and getting the clunk, I removed the caliper to remove the possibility of brake interference.

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Setting was for 2 up. Wilburs shocks.

Rebuilt driveshaft 9 months ago (I had the subtle intermittent vibration prior to that)

Final Drive seems tight at 9-3 and 12-6.

No drive fluid leaking.

 

I nearly asked him about the bike's mileage, but I found the rebuild mentioned back in the first post.

 

Also considered that the aftermarket u-joint might have a bit larger outer dimension which could touch the inside of the swing arm at certain angles, but that doesn't fully explain the intermittent, low speed nature of the vibration. Unless it's wearing it's own clearance as the miles build up...

 

:dontknow:

 

Feel like I'm kind of reaching here, probably better to wait and see what Dave can find.

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We did get the rear vibration, repeatable at will, in both directions (left and right). We did learn one thing - the vibration doesn't present itself above 18 mph.

 

Since you only feel vibrations when turning, that would point again to the tires. Look for cupping or a ridge between compounds of the tire. Check both tires.

Edited by Bernie
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I managed to get a quick ride in to the post office yesterday, just as the snow began to fall. With FD and transmission fluids warm(er), I set about trying to video the spinning wheel, showing the chalk mark. Unfortunately, after several attempts, I wasn't able to capture the chalk reference and document the sound in the same clip - the phone being out of audio range when including the chalk reference mark. Using a much different angle (now that I think about it) with the phone near the DS housing looking back at wheel might provide the magic of both at the same time.

 

My impression was that the 'clunk' sound was in the driveshaft housing area and not in the FD area - which I think DR and Larry were thinking would be U-joint?

 

Should I compress the rear suspension with a floor jack to change the pitch of the driveshaft and spin the wheel to see if the clunk disappears?

 

Tires: The rear tire is cupped. I should have 'felt' the surface to begin with. I wasn't seeing the type of obvious cupping I'd previously seen on the front tires (previous set of PR4's cupped badly in front) when I looked at the rear, so I discounted cupping. But sure enough, the 'blocks' of tread on the rear tire rise right at the leading edge of the tread, so running my hand counter-clockwise around the tire, my hand feels the 'sharp' edge of the blocks of tread - on both sides. Using just my finger starting at the leading edge, I can feel the drop in surface area as I move my finger from the leading edge.

 

 

Edited by workin' them angels
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Should I compress the rear suspension with a floor jack to change the pitch of the driveshaft and spin the wheel to see if the clunk disappears?

 

Tires: The rear tire is cupped. I should have 'felt' the surface to begin with. I wasn't seeing the type of obvious cupping I'd previously seen on the front tire when I looked at the rear, so I discounted cupping. But sure enough, the 'blocks' of tread on the rear tire rise right at the leading edge of the tread, so running my hand counter-clockwise around the tire, my hand feels the 'sharp' edge of the blocks of tread - on both sides. Using just my finger starting at the leading edge, I can feel the drop in surface area as I move my finger from the leading edge.

 

Morning Dave

 

It would sure help to compare the clunking noise a full suspension extension to partially compressed--- BUT! it is ever so easy to knock a bike off the center stand & all the way over when using a floor jack under just one wheel. I have seen some light (normal) thumping sound even on normal 1200RT's when rotating the rear wheel at full rear suspension extension.

 

I would suggest that IF you want to try a partially compressed rear suspension then ONLY apply force on the bike (not to a remote surface)

 

I usually use 2 ratchet straps between or under the final drive & the frame. That way ALL the upward forces are exerted ON THE BIKE itself so no external forces to push bike over.

 

On your rear tire wear-- that fits with the change in noise when you let the tire pressures down & also fits with added weight effecting the noise as well as lean angle effecting the noise.

 

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Thanks! I should have time to compress the rear suspension this weekend - just to run that to ground.

 

I should have felt the tires first thing. Although in my defense, the intense and noisy shudder is still MIA.

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  • 2 weeks later...

Just to follow up: I'm at a stand-still till April or so. I have a new set of rubber in the garage, but haven't had time to mount it. Starting tomorrow, I'll be nursing a wounded wing and that'll dampen/halt most meaningful activities for the near future.

 

I'll report back in late April with tire and driveshaft info.

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