View Single Post
Old 01-03-2013, 12:23 PM   #36
def
I've little to say
 
def's Avatar
 
Joined: Feb 2004
Location: The woods and mountains of Alabama
Oddometer: 8,774
Quote:
Originally Posted by Jim Moore View Post
Yeah, sure. As my 02 GS approached 100K miles I decided to do a little refurbing. Brake lines, fuel lines, pivot bearings, etc. I decided to pull the driveshaft and send it out aslo. The back end was pretty notchy when I pulled it. The front end felt fine.

I sent off to Machine Service Industry in Green Bay, WI. They sent if back a week or so later. The whole thing looked new. The u-joints rotated like butter. I was pretty pleased, thinking I had maybe dodged a bullet.

A few months later (5K miles or so) I felt a weird little vibration when I was riding, for just a few seconds. I didn't really think about it, but that night I happened to be in the garage, so I bent down and turned the rear wheel. I heard / felt the immistakeable "clunk-clunk, clunk-clunk" of a bad u-joint. I pulled the swingarm off and found the front u-joint nearly sheared all the way through. It was obviously about to give way. I replaced it with an old front half. About 10K miles after that I was accleerating from a stop light and I heard / felt a loud "CRACK," then a sound like a ball bearing rolling around in a coffee can, except a LOT louder. The bike was still under power, so I limped it home a few miles. I pulled the FD and the u-joint literally fell apart in my hands. It somehow held together enough for me to get home, but it collapsed into pieces as soon as the pressure was released. It looked like someone had thrown a grenade into the tunnel. There were pieces everywhere. The inside of the swingarm was trashed. It was a mess.

My guess is that the refurb company took too much metal away during the process. Maybe the installation of the grease fitting left the shell of the u-joint too weak to tolerate the stresses of use. I don't know.

People seem to have good luck with Bruno. I would definitely try him instead of the other guys if you plan to go that route.
My 2001 GS has a separate, removable rear u-joint that joined by splines to the rear of the driveshaft and FD pinion shaft. During assembly, the pair of u-joints must be phased correctly to eliminate rotational acceleration and deceleration speeds from the u-joints and resulting flexing of the driveshaft.

Here is the excerpt from my REProm regarding phasing...not very well explained:

Caution:

The universal joints for universal shaft and rear
wheel drive must be installed in the same position.


I am not familiar with the 2002 driveshaft design. Does the shaft/u-joint require phasing or are the splines keyed so that phasing takes place with assembly?

If not, did the shaft get installed with proper phasing when you installed the refurbished shaft?

You don't perhaps have some photos of the failed refurbished shaft do you?
def is offline   Reply With Quote