4V K bikes have a two piece drive
shaft with a U-joint at each end. It is not uncommon for
one of these U-joints to fail and 'splode after about
90-100,000 miles of use, leaving you stranded by the side of
The original drive shafts used to
be available either as a set or front (part 26111458480) or
rear (part 26112312851) half. These have since been
superceded by a
newer (possibly better?) drive shaft that includes both
front and rear halves - part 26112325746.
What Can You Do To Prevent U-joint Failure:
Since the U-joints are sealed at
the time of manufacture, without having them rebuilt ($$$),
there is no good way repack the U-joint bearings with fresh
grease to prevent them from failing.
However, when reassembling the
swing arm, drive shaft and final drive, you can minimize the
strain on the U-joints by properly
phasing the drive shaft.
Also, once the bike has reached
75,000 miles or so then it's probably not a bad idea to
check the condition of the drive shaft U-joints when
performing a spline lube or installing a new rear tire.
If any "lumpiness" is detected in either axis of rotation
then that's probably a sign of impending doom and an
indicator that the drive shaft should be replaced in the
© 2013 Drake Smith - Please do
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