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Install Final Drive


Steve_Reinig

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I just had my final drive re-built. Taking it off was easy. How is the re-install in terms of lining splines up etc. Is that difficult? Any helpful hints would be appreciated. Thanks

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I just had my final drive re-built. Taking it off was easy. How is the re-install in terms of lining splines up etc. Is that difficult? Any helpful hints would be appreciated. Thanks

As they say in English manuals... Assembly is the reverse of disassembly. Basically straightforward. There are only two things to watch for...

 

- Grease the splines with a 60% moly grease such as Honda's "Moly-60". Do not use ordinary grease!

 

- Take great care to tighten the 2 pivot bolts (on on each side) in the manner stated in the manual, and to the proper torque. The left one is tightened first to a very high torque, th4en locked with a big locknut, then the one on the right (the outside one) is tightened only to a very low torque to preload the pivot bearings. Excessive torque on that one will distort (and probably crack) the housing, and/or damage the bearings. Be sure you get the torque specs before you start! I have them for the K1200RS, and can pass them on if you want (they are probably the same), but best is to get the specific ones for your bike.

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Well, one more... When re-mating the FD's spline to the drive shaft, be sure to index it so the rear U-joint is 90 degrees from the front U-joint. This will minimize the potential for vibrations in the shaft.

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Ken:

 

Noticed your lead in.... This is the second drive on this 96 RT. The first one failed at 62,000 and the second at about 80,000. I am thinking there will not be a third failure......

 

Thanks everyone for the good advice and link to advrider.

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Well, one more... When re-mating the FD's spline to the drive shaft, be sure to index it so the rear U-joint is 90 degrees from the front U-joint. This will minimize the potential for vibrations in the shaft.

As I recall, they are perminently attached to either end of the driveshaft that way, are they not? Anyway, in my comments, I was assuming he left the U-joint on the end of the driveshaft when he pulled the angle drive off.

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The hooke's joints on either end can be rotated relative to each other to different degrees via the spline connection. You need to have these joints in phase to minimize the inherent speed variation and thus vibration.

 

The correct and incorrect phasing is shown in the attached.

766927-ujphasing.gif.366f633492d5cc2b37a379be9f4d2bdc.gif

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Well, one more... When re-mating the FD's spline to the drive shaft, be sure to index it so the rear U-joint is 90 degrees from the front U-joint. This will minimize the potential for vibrations in the shaft.

As I recall, they are perminently attached to either end of the driveshaft that way, are they not? Anyway, in my comments, I was assuming he left the U-joint on the end of the driveshaft when he pulled the angle drive off.

The rear set of splines will reconnect the front 2/3 of the drive shaft to the rear 1/3 (the part that stays with the FD) at several different places in the splines' rotation. It is important that they be engaged in incerments of 90 degrees, the rear U-joint relative to the front U-joint (the one up by the transmission).
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Flars, simple, the U-Joint caps on the center (drive) shaft must be in the same plane (ie. line up with each other)..

 

What happens on a U-joint equipped shaft when the joints are run at any angle other than straight in line is that the dive input onto the jointed shaft spins at a fixed & steady speed,, BUT as the power is transmitted through the first angled U-joint & into the drive shaft the shaft speeds up & slows down as the U-joint changes angle as it rotates.. So to get the output shaft to spin at the same (& constant) speed as the the input shaft the rear U-joint MUST be phased the same as the front U-joint.. If the center caps are phased at opposing positions the shaft will speed up & slow down as the front shaft rotates & the rear output shaft will speed up & slow down even more than the shaft (or at least at a different phase than the front angle.. Basically set up a shake & vibration problem.. Sometimes that phasing offset can be use to an advantage & is sometimes used if the shaft is also angled latterly in relation to the input shaft plane, a slight phasing offset can also sometimes cancel some off order vibrations..

 

Bottom line here is: line the center caps up with each other & you can't go wrong for most applications..

 

Twisty

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confused.gif

 

You need to look at them again, closely.

 

The first attachment shows both right and wrong with labels. The second attachment shows the correct orientation similar to the first one, just a more realistic drawing of a typical cardan shaft with a spline instead of square connection.

 

With a spline connection in the center of the shaft you can clock the joints relative to each other in as many ways as there are teeth on spline but there is only one position where the joints are phased correctly. From the side (which on the bike you cannot see due to the tube the shaft fits in) the front joint and back joint should be a mirror image.

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Bart Anderson
...Take great care to tighten the 2 pivot bolts (on on each side) in the manner stated in the manual, and to the proper torque. The left one is tightened first to a very high torque, th4en locked with a big locknut, then the one on the right (the outside one) is tightened only to a very low torque to preload the pivot bearings. Excessive torque on that one will distort (and probably crack) the housing, and/or damage the bearings. Be sure you get the torque specs before you start!...

 

Bob's instructions are exactly right, except they're exactly backward. Should be:

 

Take great care to tighten the 2 pivot bolts (one on each side) in the manner stated in the manual, and to the proper torque. The right (outside) one is tightened first to a very high torque, then the one on the left (the inside one) is tightened only to a very low torque to preload the pivot bearings, then locked with a big locknut. Excessive torque on that one will distort (and probably crack) the housing, and/or damage the bearings. Be sure you get the torque specs before you start!...

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WTF - I could have sworn that those two attachments showed different 'correct' phasing. Perhaps I had exceeded the 'do it till you need glasses' limit for that day, cuz the two 'correct' pictures now look the same dopeslap.gif...

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WTF - I could have sworn that those two attachments showed different 'correct' phasing. Perhaps I had exceeded the 'do it till you need glasses' limit for that day, cuz the two 'correct' pictures now look the same dopeslap.gif...

 

You're not alone. I too had the same initial reaction, but upon closer inspection........that's just wierd.

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