Weird noise

[johnnyb]

I just changed the speedo light on my wife's R60/7. Rehooked everything and took it for a short ride to make sure all was functioning correctly. When I started riding, there was a noise coming from the rear tranny area. The faster I rode, the faster the noise. I unhooked the speedo cable from the tranny, and the noise still happens. With the engine off, I pushed the bike forward and back in neutral, no noise. With the bike in gear, the noise is louder pushing the bike forward than it is backwards. From the sound and area, I'm guessing that the bolts that connect the driveshaft to the output flange have come loose. I'll check that first. If that's the case, can I just replace them and cross my fingers? Or is possible that there is more serious damage?
Also, (Stupid Question), is overfilling the driveshaft fluid slightly an issue?
Thanks for any help,
John

 

[krpntr]

noise at u joint?

Is the swing arm centered?

 

[johnnyb]

Just checked using feeler gauges. Looks like a difference of .039 inches from side to side. I know they are are supposed to be even, but with that difference, do you think something may be damaged?

John

 

[toooldtocare]

Just checked using feeler gauges. Looks like a difference of .039 inches from side to side. I know they are are supposed to be even, but with that difference, do you think something may be damaged?

John

No, I do not think that 40 thousands will not damage it. Remember, there is a U-joing there and no bearing in the swing arm at that point.

Drain the fluid first and look at it before you start tearing things apart. If it looks clean and the drain plug is also clean, than check other things such as the driveshaft.

Another question, since this is your wife's bike, do you normally ride it? Maybe you are not used to the noise it makes?

Wayne

 

[johnnyb]

This is a pretty obvious noise. My wife actually heard it from inside the house. Sadly, I found this issue on my last day of vacation, so it'll be a few days before I can start on it. Just looking for opinions right now.
Thanks,
John

 

[69ZEFF65]

What kind of noise

A grinding would indicate a bearing, Clunk clunk during back and forth motion would indicate loose drive shaft bolts or a wiped out universal, kur chunk kur chunk would tell me a lot of bad stuff could be happening down there. I would pull the boot back and take a look to see if its something obvious and fixable without major surgery. If your bolts are loose I would get new ones and not even try to tighten them. Check very carefully that one of the bolts has not sheared off or that a chunk of anything isn't rattling around in there.

 

[ccolwell]

A grinding would indicate a bearing, Clunk clunk during back and forth motion would indicate loose drive shaft bolts or a wiped out universal, kur chunk kur chunk would tell me a lot of bad stuff could be happening down there.

You should start the motorcycle version of Car Talk.

 

[bikerfish1100]

a description beyond "weird noise", "obvious noise" and "the noise" would be real helpful if you want some greater precision in the diagnosis.
whine, clatter, chatter, klunk, rattle, screech, ticking ????

 

[na cl k9]

Loose drive shaft flange bolts

. From the sound and area, I'm guessing that the bolts that connect the driveshaft to the output flange have come loose. I'll check that first. If that's the case, can I just replace them and cross my fingers? Or is possible that there is more serious damage? Also, (Stupid Question), is overfilling the driveshaft fluid slightly an issue?Thanks for any help,
John

It is possible to check the u-joint connection by simply grabbing the drive shaft boot with your hand, squeezing it untill you feel the u-joint and then see if it is loose in its mount by attempting to move it. If you don't get a reaction to that test then pull the spark plugs, put the transmission in gear and again, squeeze the boot this time while you turn the rear wheel. You can feel the u-joint move and, if it has bolts missing or loose, it will wobble / jump around and there will also be an accompanying noise.

If there is noise due to a partial disconnect, then there are probably several drive shaft bolts loose and perhaps "missing". It will be important to fix this problem before the bolts damage the threads on the output flange. If one or more of the drive shaft mount bolts have completely backed out then they will be found in one of two places ~ sitting in the bottom of the rubber boot or lodged between the drive shaft and housing down inside the swing arm. That will require removal of the final drive and, using a stick, push the bolts back towards the u-joint to recover them. Get new bolts, clean the area and install them with a dab of thread locking compound. Torque them to the correct spec if you can otherwise, tight as you can get them with the size wrench you'll be able to use.

When a bolt loosens, the stress of rotation will begin to loosen the other bolts in sequence. As the drive shaft flange begins to wobble, corners of the drive shaft just barely contact the heads of the bolts and cause them to unscrew quickly and also potentially wallow out the threads on the transmission flange. If a bolt has lodged between the shaft and the housing, there is a possibility the drive shaft may be scored in one or more places. Under extreme conditions, a shaft can break right on the score like it was cut with a knife. In rare cases, your u-joint may be failing. They hardly ever do but that will be the subject of a later post if it becomes necessary. Slightly over filling the drive shaft housing is not a problem.

 

[lmo1131]

Quote:
Originally Posted by 69zeff65
A grinding would indicate a bearing, Clunk clunk during back and forth motion would indicate loose drive shaft bolts or a wiped out universal, kur chunk kur chunk would tell me a lot of bad stuff could be happening down there.

You should start the motorcycle version of Car Talk.

no kidding!

 

[johnnyb]

Sorry about my inabilitity to describe a noise on the computer. There is a clunk. I did say (from sound and location), it did sound like the bolts coming loose at the tranny output.
Thanks for all the input. When I get a chance, that is the 1st thing I will look at. I was just concerned that there might be more damage if those bolts came loose. (I will check for damage also).
And now, back to Car Talk,
John

 

[lmo1131]

I was just concerned that there might be more damage if those bolts came loose.

That might be putting it lightly johnny....

 

[na cl k9]

Complete drive shaft disconnect...

What the photo was intended to illustrate is a slightly more pressing problem created by a loss of the connection between the transmission and the drive shaft. Namely that when it happens ~ that's where you are going to spend the next few hours until you either fix it or have the bike carted off. In the case of my BMW dirt bike, I too heard "the noise". Because I ignored it initially, I wound up with the bike apart as you saw, in a spot inaccessible to anything but the most robust 4WD vehicle about 80 miles west of the middle of nowhere. Rest assured if it is the bolts loosening, they will come completely out. My output flange suffered damaged threads and as a result, I could only replace 3 of the 4 bolts but that got me home and I was eventually able to get all the bolts back in place.

Shall we have a "NAME THAT NOISE" contest? Here's one you will all probably recognize: "Snap, Crackle, Pop".
If you answered "Rice Krispies" you get a gold star.

 

[bikerfish1100]

Shall we have a "NAME THAT NOISE" contest? Here's one you will all probably recognize: "Snap, Crackle, Pop".
If you answered "Rice Krispies" you get a gold star.

and i was going to go with "the sound of a 1960's Brit bike's electrical system".

 

[johnnyb]

Well Gents,
I pulled back the driveshaft boot expecting to see some bolts loosened up. No go.
I felt the u-joint. No play. I then took the bike to my mechanic, (Thoroughbred Cycles). He found that at some point, there was water in the transmission case. The noise was bearings going bad. He is trying to get the bike ready so my wife can take her own bike to the Dells Rally.
My thanks to toooldtocare, 69zeff65, and to s09rwmb for their replies to the issue. (Especially the latter). I do appreciate your input.

Thanks again,
John

 

[ebeeby]

Well Gents,
I pulled back the driveshaft boot expecting to see some bolts loosened up. No go.
I felt the u-joint. No play. I then took the bike to my mechanic, (Thoroughbred Cycles). He found that at some point, there was water in the transmission case. The noise was bearings going bad. He is trying to get the bike ready so my wife can take her own bike to the Dells Rally.
My thanks to toooldtocare, 69zeff65, and to s09rwmb for their replies to the issue. (Especially the latter). I do appreciate your input.

Thanks again,
John

Do you pressure wash your bike? How does the boot for the tach cable look?

 

[johnnyb]

No pressure washing here. I can't recall if the speedo boot was cracked when my wife bought it. I may have replaced it back then. There was no water in the tranny when Glen at Thoroughbred pulled it apart. It was his opinion that this is something that occurred with a previous owner. It just took this long for the bearings to go bad.

John

 

[helmut_head]

Next time take a picture of the noise.