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The Red K75S

Changing Alternator Drive Bushings on a K75
By Ted Verrill

Parts You Will Need:

  • 3 Alternator Bushing Sets, Part # 12-31-1-460-306 (~$9.00)

Parts You MAY Need and Should Probably Have:

  • 1 Alternator Drive Clutch Part # 12-31-1-460-302 (~$8.00)
  • 1 16 mm Spring Washer Part # 07-11-9-933-155 (~$0.70)

Tools/Things You Should Have:

  • 1 Tube Dielectric Grease
  • 1 Lubricator s/a Armour All
  • 1 tube Red Loctite

For the Battery Tray and Mounts:

  • 4 Battery Mounts, Part # 61211233028 (~$1.20 Each)
  • 4 6mm Wave Washers (~$0.15 Each)
  • 4 6mm Nuts (~$0.15 Each)
  • 1 Krylon Spray Paint Black (~$3.50)


Part I: Disassembly

  1. Put the bike on the center stand.
  2. Remove the seat.
  3. Whenever I do a job like this I use a clear plastic multi-compartment box to keep all of the screws and circlips both separate and in one place. Try Wal-Mart, around $3.00.
  4. Remove the alternator shield (2 hex bolts)
  5. Remove the computer and the housing.
  6. Remove the coolant overflow tank.
  7. Carefully examine your overflow tube at the overflow tank connection, mine was so dry-rotted it almost broke in half!
  8. Remove the battery.
  9. Check your water levels while the battery is so accessible!
  10. Remove the battery tray (and mounts if have decided to replace them.)
  11. Disconnect the alternator electrical connection.
  12. Then, Remove the three 6mm allen bolts that hold the alternator.
    An Allen extension is quite handy on the top and especially the bottom bolts.
  13. Optional: Remove the battery tray. Remember that removing the battery tray makes removing and replacing the bottom bolt much easier, plus yours probably needs new nuts, bolts, mounts and a good repaint like mine did. Brush down the battery tray with a wire brush to remove old paint and oxidation. Wash it with a really good scrub-brush and a good cleaner (I used Simple Green), and thoroughly dry it. To paint the tray, hang it from a stretched-out coat hanger through one of the mounting holes and repaint it using newspaper behind/below to catch stray paint.
  14. Carefully pull the Alternator slowly out, toward the back of the bike. Make sure to remove any bits and pieces of the alternator clutch or old bushings that fall out.

Part II: Examination

Remove and examine the bushings. If they are deteriorated, melted, or even missing you will have to very carefully examine the alternator clutch. You may even want to eat the $8.00 to be on the safe side and replace the Clutch anyway. Carefully examine the alternator clutch fins as well as the driven gear that engages the clutch (a flashlight helps here.) The Alternator Clutch Fins may have very fine hairline cracks, or may be bent, in either case you will have to replace this inexpensive part. If yours is fine and you don't want to replace the alternator clutch, move on to Part IV.

Part III: Remove & Replace the Alternator Clutch

To remove and replace the clutch, insert an Allen wrench through an angle-head box-end wrench and into the shaft. Hold the Allen wrench steady whilst removing the nut with the box-end wrench. You may have to cycle heat the nut with a butane torch if it is particularly stubborn. This is a little difficult and requires careful application of elbow grease. When the nut is off, remove and discard the spring washer and lift off the clutch. Watch carefully at this point for the Woodruff key. I have been told the key is not needed and in fact many K bikes don't even have it. YMMV.

Position the Woodruff Key (if using it) and place the new Clutch onto the alternator. Place a new spring washer on the alternator shaft over the Clutch and use a little Red Loctite on the shaft threads before hand tightening the nut. Tighten to the correct Torque setting (I have no torque wrench so I just tightened it until I felt the spring washer had compressed, in other words "real tight".)

Part IV: Replace Alternator Clutch Bushings, Remount Alternator.

Position the three alternator bushings in the alternator clutch and at each juncture where two bushing "pods" meet (where the alternator drive's fins will engage) apply a small amount of lubricant (I used Armor-All and it worked quite well though I hear spit will do in a pinch.) On the outside of the alternator clutch you will see three marks, each at a spot where the alternator drive's fins will insert into the alternator clutch bushings.

Here it really helps to have a partner on the other side of the bike to hold the alternator steady while you line up the clutch, and then hold the clutch steady and lined up while you gently push the alternator onto the drive.

First, line up the alternator so that it does not need to be rotated in order for the three mounting bolts to be replaced. Second, rotate the alternator clutch such that one of the three marks is lined up with one of the three drive fins (again, a flashlight is handy here...) Then simply slowly and gently push the alternator into position. You will feel a little resistance at first, but the alternator should evenly slide right onto the drive fins.

Repeat this procedure if necessary...

Tighten the mounting bolts to spec (again, "tight") and clean, lube with dielectric grease, and reattach alternator electrical connections. Reassemble in reverse order (remembering to replace the battery mounts, and to clean and lube the battery connections with dielectric grease.)

PART V. Go For A Ride!

NOTE: You may want to inspect/replace the alternator brushes. It is simple, but not covered here...If you have had any charging problems, do it.

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