U joint? Clutch, thumping

[Gavin_Sons]

Been having a thumping feeling in my pegs under slack drive line conditions. Rode 300 miles yesturday, and it was doing it again. But when I pull in the clutch it would stop. Everything in the drive line is tight. Could it be the clutch? Im open to any ideas, im about to forget about it and ride til it blows up then ill know for sure what it is

[matt]

if you have engine off bike in first gear does it have alot of movement if you roll bike foward and back?  If so check you dampners,and gears make sure there is no wear (splines,hub) if all looks good check pinion then u joint I think bike normally has about six inches of movement

[Patrick]

'Everything in the driveline is tight'.. OK,, but,, what does it mean ??  Have you had this monster apart to check everything ??  If so,, was it put back together correctly ??  Maybe a couple of dumb questions,, but,, had to be asked,, stuff happens.. I agree with Matt..

[Gavin_Sons]

It does only move about 6 inches in gear. And yes everything was put back together correctly. When I had it apart everything was tight and looked brand new. Splines, pinion cup u joint. But now the thumping feeling has started on a slack drive line. Like I said if you pull the clutch while its happening it stops. I would think it would happen with the clutch engaged if it was the u joint. Oh, dampners look good also.

[Ricky-D]

I would think it would happen with the clutch engaged if it was the u joint.

Not necessarily!

The slop (in the spline) between the u-joint and the output shaft at the motor is most likely the cause of what you feel,

Although, what you feel is also a precursor of a failing u-joint.

I'd suggest to look at the u-joint again.

***

[RP#62]

Worn rear wheel dampers will do it too.
-RP

[Gavin_Sons]

I would think it would happen with the clutch engaged if it was the u joint.

Not necessarily!

The slop (in the spline) between the u-joint and the output shaft at the motor is most likely the cause of what you feel,

Although, what you feel is also a precursor of a failing u-joint.

I'd suggest to look at the u-joint again.

***

Ill just order me a new one and replace it and see where we are then. Thanks Ricky-D

[scoobydoo]

Gavin, I'm having the same problem. When the drive line is slack, can feel it in the pegs. Kind of a bumpimg. It seemed to show up after I went Darkside. If I keep the slack out, everything is ok. Does not feel like a viberation.
Let me know what you find, I'm hoping to wait until winter the look for the problem.
Scoobydoo

[Gavin_Sons]

That is when it started for me too. I think it is from going darkside and having more traction, you feel the little bit of slack the drive line has. I have a spare rear wheel with a mc tire mounted. I may swap them out and see if it still does it. Other than that im not going to worry about it. If something blows up ill know then what it was. Rode 300 miles saturday with no problems, except for a killer hornet that decided to enter the vent of my IS and ride on the speedometer for 20 miles. At a stoplight in bloomfield I pulled up next to steve and flicked it off and it flew to the top of his motor. After stopping at DQ and using my pocket knife we finally got it out.

[Ricky-D]

I hate to be a conveyor of bad news but my feeling is you will not be able to rid you Valkyrie of this specific u-joint vibration.

It, the vibration, may alleviate with a new u-joint (mine did) but time was not long before the vibration returned.

I now live with the vibration.

Knowing that the vibration is ever present I find it easy to avoid those instances where it becomes annoying. It is all in throttle control and how you ride the bike.  It is normally only at higher speeds where it occurs, most my riding is local and on the interstate,,, it's easy to control.

***

[scoobydoo]

If I ease off the throttle instead of just rolling off quickly,  no sound or bumping. Just don't like not knowing for sure if something is going to break. Always in the back of my mind when on a trip.