U Joint Driveline question

[Lyle Laun]

Need some advice/wisdom.....
My bike developed a clank at low speeds (sounded like the kickstand was banging up against the exhaust). Noticably worse after another 60 miles of riding, started to vibrate a bit at speed. Shut down and called the tow truck. Fairly loud clanging and banging at low speed, assumed it to be the ujoint. Got it home and tore it down. The pinion cup and drive shaft shows some wear but didn't look too bad. Not an issue as I was still thinking u joint. Pulled the u joint and it looks good (no flop, no play). Put it in the vice and it seems tight. Had a good look at the differential, the drive flange teeth are very good and so is the teeth on the rim side of the wheel. I can turn the pinion cup freely and it feels smooth and doesn't seem to have any excess play in it. Everything looks ok regarding the grease, nothing was dry.

As everything is apart I plan to go ahead and put in a new u joint anyway and see if that cures it. If it doesn't cure it than I guess I will put in my spare differential.

Has anybody else had a bad u joint that seemed ok when you took it out ?
Any chance I've just got a wheel bearing going out ? Mine felt ok but I don't know what they sound like when they fail.

Thanks in advance
Lyle
Any info or experience would be appreciated.....

[John Schmidt]

You can't tell about a u-joint by putting it in a vise and twisting it. I use a large square shafted screwdriver and slip it in next to the cross piece and twist the screwdriver. That will try to separate the two halves longitudinally/lengthwise rather than by twisting the two halves. Often you'll not feel anything abnormal by just twisting, but by trying to separate the two sections as described it will show looseness not otherwise noticed. You need to pry them apart, most don't have the human strength to apply enough pressure at the right spot. If you need a picture of what I'm talking about, let me know and I'll post one here later.

[Bighead]

Helped a freind last summer and he swore it was his U-joint and ordered another we gore it down and all splines looked new and U- joint was good turns out it was the rim. The inside where the shaft goes through the bearings had broken some how when we removed the tire the bearings fell out.

[bill-jr]

Left side rear wheel bearing ....

[Smokinjoe-VRCCDS#0005]

Left side rear wheel bearing ....

My bet as well ( been there , done that ) even made the sound and feel you described. Go with the double roll bearing mod see Grumpy for a spacer.

[Lyle Laun]

Guys
Took John's technique and verified it wasn't the u joint. Re-assembled the u joint ( also used the roll up the boot trick -10 minutes).
Then took Billjr & SmokinJoes advice and checked the left wheel bearing. It's rough when I spin it, will put a new one in and should be back in business. In hindsight, I should have checked that first as there wasn't any slop in the driveline and the clanking wasn't consistant with on or off the gas.

This board rocks ! Thanks everyone for the help !

[mauigts]

How many miles are we talking on your bikes. I just croxxed the country, and developed a similar knocking noise, making me think u joint. My bike has only 45K on it. I just wore the rear tire out upon arrival and put a new tire o  the rear. I did take the rear wheel off, but didnt pull the bearings. I left the wheel with a local bike mechanic, who changed tne tire. He didnt mention anything to me about the bearings, and I reinstalled the wheel, and checked it for smooth rotation. The noise is definately coming from the areaa of the u joint, and you do feel as if there is some "gap play" making the sounds you here. I am just a bit confused as all the reading I'm doing is telling me that everyone is suspecting a bad u joint for this kind of knocking, then finding out, its not..... and my bike only has 45K on it. All the miles are long road trips of  3 to 8K trips. Any suggestions, and or input, thanks

[F6Dave]

My LR wheel bearing failed at around 50,000 miles.  There was a rash of failures and I think Honda maybe got a bad batch from a supplier.  The dealer sole me the wrong bearing so I bought a 6204-2RS from NAPA for half the dealer's price.  125,000 miles later that bearing is still fine, which supports my bad batch theory.

Guys
Took John's technique and verified it wasn't the u joint. Re-assembled the u joint ( also used the roll up the boot trick -10 minutes).
Then took Billjr & SmokinJoes advice and checked the left wheel bearing. It's rough when I spin it, will put a new one in and should be back in business. In hindsight, I should have checked that first as there wasn't any slop in the driveline and the clanking wasn't consistant with on or off the gas.

This board rocks ! Thanks everyone for the help !

[Lyle Laun]

Mine went at about 50k miles. Sounded like the ujoint but no real play in the driveline

[Gabriel]

I noticed today that I had a vibration above about 80 (I wasn't looking) and it would get pretty bad real quick, accelerate, decelerate, coasting changed nothing.
It felt like a bad u-joint so I tore it down (took about 30 minutes) and could not actually say I found anything bad?
however it felt so much like a bad u-joint that I studied the u-jount and it had what I would say was a barely detectable amount of play. (it would pass in the auto industry)
I could only see the movement but I could not feel it so I chucked it up in a vice on one end and locked some vice grips on the other and there it was, I could feel it now and it was about a 1/16th of an inch total movement in any plain.
A good u-joint should have no play what soever and will probably even feel stiff.
So now I have to find a new one, I may post in the classified because I know people bought spares and may now want to part with one?

[hubcapsc]

I noticed today that I had a vibration above about 80 (I wasn't looking) and it would get pretty bad real quick, accelerate, decelerate, coasting changed nothing.
It felt like a bad u-joint so I tore it down (took about 30 minutes) and could not actually say I found anything bad?
however it felt so much like a bad u-joint that I studied the u-jount and it had what I would say was a barely detectable amount of play. (it would pass in the auto industry)
I could only see the movement but I could not feel it so I chucked it up in a vice on one end and locked some vice grips on the other and there it was, I could feel it now and it was about a 1/16th of an inch total movement in any plain.
A good u-joint should have no play what soever and will probably even feel stiff.
So now I have to find a new one, I may post in the classified because I know people bought spares and may now want to part with one?

I saw your post on the classifieds... For a while, Honda didn't have any,
but there's plenty now... I just looked on partzilla and Amazon too...

-Mike

[Gabriel]

Thanks Mike,
I'm still wondering if a u-joint with only this much play could cause what I'm feeling.
The splines are tight on both ends, so that's not an issue. The joint looks brand new and I talked to the previous/original owner and he said he often had it to 100mph and it was butter smooth.
I've owned the bike for about two months and have put maybe 500 miles on it.
I'm going to put it back together and look elsewhere.
There is something else; two days ago I put dyna beads in the front tire, now this should not be a problem because I have used them for years, that is unless someone put in some liquid tire sealer!

That's what prompted me to contact the PO but he says he never used any of that stuff, I believe him however he does not do any of his own work so who knows for sure.
I don't recall this bike having vibration above 80 but I'm not there often and maybe never with this bike before yesterday?

There's something else; I don't believe I have ever felt a bad u-joint that only showed up at speed and was not effected by load. This vibration starts small and gets big quick, decelerating, accelerating, or coasting with the clutch in does not change it at all.

I'm thinking there is something that has those Dyna beads in a group, we will see. I'll be back!

[hubcapsc]

I felt a high speed shudder a few times last year, and thought u-joint.

I did the "vise/channel-lock" thing and felt a little give.

I replaced the u-joint.

I've never felt the shudder since... not scientific, but it makes me
feel good to have done it...

-Mike

[Bighead]

Gabriel I think Mike is on the right tract the U joint shouldn't have any play in it.

[Gabriel]

We will certainly find out, I don't feel bad about taking this bike apart, it gave me a change to lube all the splines and inspect a lot of parts and it's already completely back together.
If this application cannot tolerate this small amount of play then it is unique because as I said earlier if this were in an auto it would pass as good.
I did this for a living for 30 years and even though most of the drive lines I saw were equipped with constant velocity joints, I have inspected at least 500 drive shafts with u-joints and replaced about 100 of those, but that does not mean this design is the same and not less tolerant of clearances.
Of course I'm eyeballing the amount of movement exhibited while in the vice, I could have put a dial indicator on it I guess.
I'm OK with taking it apart again, it's not that difficult. I have a lift and all kinds of jacks and tools.
I don't see how some of you guys work off the floor, for example re-installing the drive boot was easy, I have a pneumatic stool I sat on with one hand under the bike and the other on top, it went right on.

I don't want to throw a lot of parts at this and not know what actually fixed it, so the only thing I changed so far is the three O-rings in the hub and differential.

Next; I'm pulling the front wheel, we will know what actually happened in time. I enjoy this stuff...

[Gabriel]

I decided to jack up the swing arm to get the tire off the lift and run it .
I took it to 5500 rpm in 5th gear and there is no vibration at all, well a little bit from tire balance but very little.
So I conclude from this that there is nothing wrong with the drive train. this simulation mimics the speed except for the engine load and the additional weight of me.
Surely I should have seen something if it were there?

Next; have a look in the front tire. 

[indybobm]

I decided to jack up the swing arm to get the tire off the lift and run it .
I took it to 5500 rpm in 5th gear and there is no vibration at all, well a little bit from tire balance but very little.
So I conclude from this that there is nothing wrong with the drive train. this simulation mimics the speed except for the engine load and the additional weight of me.
Surely I should have seen something if it were there?

Next; have a look in the front tire. 

Just something to think about, this also unloaded the rear wheel bearings somewhat.

[Gabriel]

I decided to jack up the swing arm to get the tire off the lift and run it .
I took it to 5500 rpm in 5th gear and there is no vibration at all, well a little bit from tire balance but very little.
So I conclude from this that there is nothing wrong with the drive train. this simulation mimics the speed except for the engine load and the additional weight of me.
Surely I should have seen something if it were there?

Next; have a look in the front tire. 

Just something to think about, this also unloaded the rear wheel bearings somewhat.

I think I mentioned that in an above post.
This vibration is speed related only, I can grab the clutch and nothing changes, I can let completely off the gas and nothing changes, I can modulate the throttle up and down real easy while this is going on and nothing changes.

I'm fairly sure I know what happened; I called Dynabeads this morning and the first thing he asked "did you leave the existing weight on the wheel" I said yes, he said that is the problem. I won't go into detail here as to why this is a problem but I have done this before and did not have an issue because I added a very small amount.
This time I put in what I thought was 1oz because I thought the bag of beads was a 2oz bag, it was a 4oz bag so I put 2oz in. So this amounts to my screw-up!
I pulled the weight off the wheel and will try it later, for now I pulled the rotors so I could polish the wheel, I also polished the lower fork legs also. 
I will post back soon

[Cracker Jack]

I decided to jack up the swing arm to get the tire off the lift and run it .
I took it to 5500 rpm in 5th gear and there is no vibration at all, well a little bit from tire balance but very little.
So I conclude from this that there is nothing wrong with the drive train. this simulation mimics the speed except for the engine load and the additional weight of me.
Surely I should have seen something if it were there?

Next; have a look in the front tire. 

Just something to think about, this also unloaded the rear wheel bearings somewhat.

I think I mentioned that in an above post.
This vibration is speed related only, I can grab the clutch and nothing changes, I can let completely off the gas and nothing changes, I can modulate the throttle up and down real easy while this is going on and nothing changes.

I'm fairly sure I know what happened; I called Dynabeads this morning and the first thing he asked "did you leave the existing weight on the wheel" I said yes, he said that is the problem. I won't go into detail here as to why this is a problem but I have done this before and did not have an issue because I added a very small amount.
This time I put in what I thought was 1oz because I thought the bag of beads was a 2oz bag, it was a 4oz bag so I put 2oz in. So this amounts to my screw-up!
I pulled the weight off the wheel and will try it later, for now I pulled the rotors so I could polish the wheel, I also polished the lower fork legs also. 
I will post back soon

I can see no logical reason why leaving the weight on the wheel or putting extra beads in the wheel could cause a problem. If you don't mind, I'd like for you to go into more detail as to why this caused a problem. Some others might like to know also.

[Gabriel]

The term he use if I remember correctly was harmonic oscillation, he said this would run throughout the bike and usually manifest itself in the front forks because they were the weakest kink and I have to say that is what it felt like.
The whole bike was shaking and then it felt like it moved into the front end but it still shook the whole bike.
I told him it bordered on violent and he said yes it could, he also asked if the bike had bags and I did not ask him why he asked that.
I said I thought the beads would not even consider the wheel weight in the process and he said that's wrong.
He was fairly adamant about it no matter what I threw at him, he said ditch the weights and your problem will go away.
Well here is what your waiting for; he was absolutely correct! I removed the weight and it no longer did that.
I do still have a little vibration coming from what feels like the rear, which is what I felt when I spun the tire up on the lift yesterday.
It feels like balance because it starts in at about 80 and fades as I approached 90, though it did not go away, it did change.
Of course that could be the slight play I saw in the u-joint doing this as well?
 
I will be chasing that also and time will tell...

[Gabriel]

Update;
As I last said I still had a small amount of vibration remaining @ 80MPH. I looked at the tire and discovered three wheel weights scattered around 1/3 of the wheel circumference!
I removed the weights and added 2 ounces of Dynabeads and then test rode it. I now only have a slight vibration at 80/85.
So I ordered a new U-joint and boot. (boot because it's 17 years old, even though it looks good).
results soon... Or I may weight until I replace the rear tire?

[Gabriel]

Well I got up this morning and decided to do some work;
I replaced the u-joint
Replaced the cush drive pads
Replaced the boot
Replaced the brake pads- lubed the pins
Replaced the shock grommets -polished the shock towers
Right as I was installing the second bag it started to rain! I cleaned my tools, put them away and shut the garage door.

A test ride is somewhere in the future. I'll be back!
 

[Gabriel]

Finally got a test ride in this morning and I can report that all is well.
No more vibration, smooth as glass.

[The emperor has no clothes]

Finally got a test ride in this morning and I can report that all is well.
No more vibration, smooth as glass.