balancing universal joint?

Happy new year to all.I have replaced the bearings in my final drive,a 1994 R1100RS,and noticed that the pivot bearings need to be replaced.I found little rollers and the plastic housing was damaged.So,I ordered the updated kit from Mr. Cutter,while waiting for them to arrive I pulled the rear portion of the rear universal joint from the pinion gear splines.Once I had the joint(universal and no others, Ha Ha) out,I noticed markings on the pinion gear face,numbers.Is it important to have the universal joint go back on in the same position?Do the #'s on the gear be alligned with any markings on the universal joint?I am not certain that I have not moved the the gear shaft.Thanks in advance

No; the rear part of the driveshaft is not phased to the pinion splines. It should be phased to the front part of the driveshaft just on principle, but that wasn't done at the factory and most bikes are fine without it.

Phasing is pretty easy to do, and is worthwhile in my opinion.

Look forward into the swing arm and note the position of the front universal joint. Engage the splines so that the rear universal joint is the opposite (90 degrees different).

I take the transmission out of gear and turn the shaft until the front yoke on the front universal joint is horizontal making the rear yoke on the front universal joint vertical; then put it into gear to hold it.

I then turn the final drive until the rear universal joint is the opposite: that is the front yoke is vertical and the rear yoke is horizontal. I then put a reference paint mark on the hub for visual reference.

When I engage the splines and slide the unit forward I make sure that my paint mark is lined up where it is supposed to be.

Paul,
Is this type of phasing unique to the BMW driveshaft? From what I have read, the two universals are "in phase" when their orientation is the same.

Anton,

Are you saying that they come from the factory with a random orientation?

MrFrank said:

Are you saying that they come from the factory with a random orientation?

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Yes, except for the GS Adventure which is keyed.

MrFrank said:

Paul,
Is this type of phasing unique to the BMW driveshaft? From what I have read, the two universals are "in phase" when their orientation is the same.

Anton,

Are you saying that they come from the factory with a random orientation?

Click to expand...

No - this is not unique to BMW. You want the acceleration through the first joint to be offset by equal deceleration through the second joint and you accomplish this by orienting the "input" yoke of each joint 90 degrees different.

My source for this wisdom, among others, is an engineering paper by Barry Ardell titled "Diagnosing Machines with Universal Drives" by Barry Ardell presented at Enteract 2000. It is an excellent detailed piece on universal joints and drive lines. I have it in .pdf format and can send it by email to anybody who would like to read it.

The illustration below shows two universal joints correctly phased. The intermediate shaft between the two joints is a bit longer on your Paralever bike though.

Thanks for the picture link, Paul. I misread your text to mean just the oposite.

MrFrank said:

Thanks for the picture link, Paul. I misread your text to mean just the oposite.

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Here is another illustration, from a bit more of an agricultural source, but a good illustration of correct and incorrect nonetheless.

I have found trying to explain this in words a bit daunting on more than one occasion. I have now gone back and captured a couple of illustrations which make trying to describe it a bit easier; for me at least.

I am curious of the benefit of the "phasing". Could you forward the paper to me? Thanks,
Jim J

shoeman said:

I am curious of the benefit of the "phasing". Could you forward the paper to me? Thanks,
Jim J

Click to expand...

Jim,

PM me your email address and I'll send it to you.