Clunk, Clack somewhere

[Knapdog]

I understand that our Valks make all sorts of noises and most I now ignore.
I will ask this question though to put my mind at rest as others must have heard it on their bikes...
When throttling off and coasting/slowing down at slow speeds I get some intermittent light clicks and clacks from somewhere that disappear if I pull the clutch in.
With only 14500 miles done I'd be surprised if anything is wearing away but does anything need tensioning, adjusting, lubricating or something?
Just asking in case someone can point me in the right direction.
I could live with it if it's not a problem.

[Jess from VA]

The two things that come to mind with clunks are wheel bearings and Ujoints.  

Maybe not when pulling the clutch in disappears the noise, but remember that takes stress (mechanical connection of gears to drive train) off the drive train, so those two could still be players.  Clutch in also quiets the bike, making noises easier to hear.

And worn (and aged) rubber rear wheel dampners can add slop to the drive train, most noticeable when goosing or releasing the throttle.
 
A failing Ujoint is often felt in the foot pegs as thumping.  Wheel bearing failure is more grinding than thumping.

IHMO, the most likely (of all) wheel bearing failures is the single row rear left.

And I've had a suspicious clicking at slow rolls turn out to be a chunk of gravel in a tire tread.  

[Chrisj CMA]

I agree with Jess and would add pinion cup splines. Either way the sound certainly seems drivetrain related. I’d pull everything and check. Have you had the rear end apart yet?  If not it’s something needed anyway and you need to read up. It’s a technical procedure. I posted a slideshow to guide you. It’s on shoptalk.

[Knapdog]

I agree with Jess and would add pinion cup splines. Either way the sound certainly seems drivetrain related. I’d pull everything and check. Have you had the rear end apart yet?  If not it’s something needed anyway and you need to read up. It’s a technical procedure. I posted a slideshow to guide you. It’s on shoptalk.

I've done a full rear drive service by changing all the o-rings and seals and moly greasing the splines and shaft.
I haven't done anything regarding removing the rubber gaiter and inspecting the u-joints.
If anything it's not so much a clunk as a lighter sort of intermittent tapping "tack" sound,  if you get my drift.
There's nothing loud, heavy, grinding or juddering about it.
It appears when I've throttled off and I'm coasting at slow speeds. It's as if there's some play somewhere and the sound is the "play" being taken up.
I repeat that it surely can't be something that's heavily worn with only 14500 miles done.

[Jess from VA]

Sometimes the brake pads click a little.  The pins they slide on can get corroded and dry.  The pins get grease, not the pads.

Chacing Valk sounds can be frustrating. 

Sometimes you put it on the lift and go around shaking, wiggling, banging, tapping.  And it can be run in gear carefully, while you walk around listening and inspecting.

[Doug B.]

My bet is the pinion gear and related drive shaft parts. Had the same problem recently with my 98 Tourer. Was indeed the “propeller shaft” and not the u-joints.

[Knapdog]

My bet is the pinion gear and related drive shaft parts. Had the same problem recently with my 98 Tourer. Was indeed the “propeller shaft” and not the u-joints.

What did you then do, Doug?

[Chrisj CMA]

My bet is the pinion gear and related drive shaft parts. Had the same problem recently with my 98 Tourer. Was indeed the “propeller shaft” and not the u-joints.

What did you then do, Doug?

Anytime I’ve seen a pinion joint fail. And I’ve it seen three times it was associated with a failure of the oil seal on the drive shaft. This repair requires a new drive shaft, new oil seal and new pinion cup. It’s around a hundred dollars for parts and installation is no harder than a normal rear end service.

[98valk]

My bet is the pinion gear and related drive shaft parts. Had the same problem recently with my 98 Tourer. Was indeed the “propeller shaft” and not the u-joints.

What did you then do, Doug?

from post on mine
https://www.valkyrieforum.com/bbs/index.php/topic,116696.40.html

So my conclusion is to make sure the U-Joint splines are correctly lubricated, to prevent the drive shaft to final drive splines aka spline coupling (SC) from wearing out. I also installed a new driveshaft to spline cup seal every other tire change.

The SC in a perfect application would have zero forward/rearward movement and would be submerged in oil which would result in zero wear and fretting. Fretting is a type of corrosion which gives that rust powder look. Is not from water intrusion. In some applications they actually glue the splines together to stop movement.

Honda provided the locking spring clip on the SC end of the drive shaft to help reduce movement of the SC, but it is still not a solid zero movement connection. So this is where the lubricated U-joint splines come into effect, thereby doing all of the movement, to reduce or actually eliminate any SC movement.

In a few of the links I provide it is stated that the SC splines should be hardened to greatly reduce wear.  Did Honda do this to the parts?, it doesn't seem like they did, since that would have been a much higher cost.

In my case I inadvertently mixed greases with different bases for the u-joint splines, by re-greasing and not cleaning off the old grease.
My fault, at the time, I didn't realize they had different bases. So what happened the greases started to dry out and not provide the easy sliding movement as needed and the SC failed in 17k miles.

For re-installing the U-Joint boot I coated the inside lips with silicone grease and it pops on with zero problems. suggest not to use a silicone spray which has petroleum products in it and other things which could degrade the boot material.

So to bring this all together, proper lubrication of the u-joint splines is extremely important and should be done every tire change to protect the SC. 
This time I used moly bearing chassis grease for the U-Joint for even more friction reduction and easier sliding.

For the SC I mixed TS-70 moly paste with some high temp grease so there would be about a 50/50 moly to grease ratio as recommended by the Dan Foss pdf which is a much higher percent of moly than the 3% moly grease the Honda manual calls for.

The following documents have some very good info about SCs and lubrication requirements.

https://www.machinerylubrication.com/Read/693/fretting-wear

https://www.powertransmission.com/issues/0214/spline-couplings.pdf

https://assets.danfoss.com/documents/76142/AI152986482538en-000304.pdf

https://www.eng-tips.com/viewthread.cfm?qid=423609

https://gearsolutions.com/departments/tooth-tips-a-brief-overview-of-splines/

https://www.eng-tips.com/viewthread.cfm?qid=383504