Clutch Maintenance

Most of the clutches used in the vintage era, from 1963 to 1984, used metal to metal clutch plates.  This article will cover these models.  

The need for maintenance comes about because of noticeable dragging and/or slipping.  There are a number of ways to go about correcting or reducing these problems.  Before delving into the mechanical parts of the clutch, change the oil.  This may clear up many of the problems.

Most of the clutches used in the vintage era, from 1963 to 1984, used metal to metal clutch plates.  This article will cover these models.

The need for maintenance comes about because of noticeable dragging and/or slipping.  There are a number of ways to go about correcting or reducing these problems.  Before delving into the mechanical parts of the clutch, change the oil.  This may clear up many of the problems.

Tools:  SAFETY GLASSES, Common screwdriver, (and small common screwdriver if there are anti rattle springs) long nose pliers, 10 inch channel-lock pliers, 17mm socket and ratchet wrench.

Steps of Procedure: Disassembly

1.Place your motorcycle so you can remove the primary cover.

2.Drain the primary.  (This is also the transmission on the 123/172 Cota and other models in like design.

3.Remove the clutch cable.

4.Remove the primary cover screws.

Note: Place something to catch the oil that remains in the primary before removing the cover.

5.Either tap with a small dead-blow hammer or press the clutch arm to break the seal of the gasket.

Disassembly:

1. Place your motorcycle so you can remove the primary cover
2. Drain the primary.  (This is also the transmission on the 123/172 Cota and other models in like design
3. Remove the clutch cable
4. Remove the primary cover screws. Note: Place something to catch the oil that remains in the primary before removing the cover.
5. Either tap with a small dead-blow hammer or press the clutch arm to break the seal of the gasket
6. Remove the cover.  Locate the bronze plunger and 3-finger plate.  Remove and place with the primary cover

 You have now exposed the clutch assembly and primary gear.  To remove the clutch pack you will need to remove the thin nut that secures the clutch pack to the clutch basket.  This is right hand thread so it is removed like most fasteners. 

1. Flatten the lock tab.  A small cold chisel, punch, or old common screwdriver can be used.  Any light hammer may be use to drive the bent tab down. Note: If you are removing a clutch pack from a Cota 247 or equivalent with an external flywheel weight, it will be necessary to remove that weight to have clearance for the clutch pack.  Don’t worry about the pinion gear coming off.  The pinion gear is held on by a taper fit.  The weight is held by a nut and washer.  It won’t spin because it is  keyed.  If an impact driver is used to remove this flywheel there is the possibility that the pinion gear will pop off.  This is not a problem.  You can fix this later.
2. Using a 17 mm socket and appropriate wrench, loosen and remove the nut and lock tab. Note: I have folded a paper towel into a tight square and placed it between the pinion gear and ring gear to lock the two for removal of the nut and reinstallation later.  The cases and gears are stronger than the towel and will tear the towel up before causing mechanical damage.
3. If there are 3 anti-vibration springs, remove them now.  Wear safety glasses.
4. Pull the clutch pack from the clutch basket.  A small common screwdriver can be used to encourage this removal but most clutch packs can be removed by hand.
5. Place on a clear bench top.  Lay out the channel-lock pliers and long-nose pliers.
6. Grasp the clutch pack and, using the channel lock pliers, compress each spring and remove the dowel pin.  If you can’t remove the pin with your fingers, this is what the long-nose pliers are for.
7. Remove each spring, spring pin, and dowel and place them in a place you can reach later.  You don’t want to lose any of these items by knocking them onto the floor.  They grow motors and motor away to parts unknown.
8. Remove the inner and outer clutch plates and stack them.
9. Take the top two plates.  Flip one over and place it on the other.
10. Pinch them together.  If a gap forms, they are warped.  You can check all of them this way if you like.  When through, restack them in the order they were removed.
11. Clean each in turn, starting with the bottom plate, lube with a few drops of the oil you will use on reassembly, while placing them back on the hub they were removed from.

Reassembly:

1. Using the channel lock pliers, reassemble in reverse order of the disassembly.  While assembling you will notice reference notches and an angled cut on the driving plates.  They should be stacked with all notches and cuts aligned.
2. You will note that the clutch pack will not fit into the ring gear basket without alignment of the tabs.  Use the channel lock pliers to even the tabs at enough places so it will fit.
3. If there was a spacer washer behind the clutch pack, be sure to install it before the next step.
4. Now is the tricky part.  You have to align the clutch basket tabs and the inner hub grooves for the clutch pack to fit.  The pressure plate of the clutch pack has a rectangular hole where the lock tab fits.  You can see the inner driven hub through this hole.  With a little patience you will be able to see how the tabs fit together.  You may have to rotate either or both the outer basket and the inner hub before they will align.
5. Once the clutch pack is pressed home replace the lock tab and nut.
6. Torque the nut to 14.5 to 18 ft. lbs. (2 to 2.5 m/kp.)
7. Re-bend the lock tab.
8. Re-hook the anti-rattle springs if present.
9. Replace the 3 finger plate and bronze plunger.
10. Using a new primary gasket, replace the primary cover.
11. Refasten the clutch cable.
12. Refasten the clutch cable. Note: You can use a thin smear of Hylomar gasket dressing to reduce weepage.  This stuff won’t glue itself to the gasket or engine cases and you may be able to reuse the primary gasket if you have to remove it later.

 If the pinion gear had come off when the flywheel weight was removed, clean both parts of the taper with alcohol or electric contact cleaner and re-torque to 72 lbs. ft.  You can grip the weight in a vise with soft jaws. 

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