I have been chasing a dragging clutch issue on my 1968 (aka ‘67) CA77 (18,500 miles) that I have not been able to resolve, so What did I Miss?
Problem: Clutch will intermittently not disengage transmission. For example, coming up to a Stop sign I pull in the clutch and the engine is still (slightly) connected, or sitting at a stop sign with the clutch in and the engine still has a slight pull. “Blipping” the throttle will release the clutch in both of the examples above. Stopping at the next Stop sign and the clutch may respond as it should… or maybe it won’t. One Up/Down shift may be smooth as silk and the next one may be hard and noisy. The problem is not consistent, but it is there about 75% of the time.
What I have done so far:
- I bought Bill Silver’s Dream 2010 CD and read most of everything he has there, and I have searched and read most of the clutch information here on this 305 forum.
- Adjusted the clutch (Right/Left/Right, back 1/8”), Lever at about 1/8” free-play – No Change
- Removed, Checked, Lubed, reinstalled Clutch Cable – No Change
- Disassembled Right gear case, Cleaned/Checked/Lubed Clutch Lifter Assembly, Rod, Ball. Measured Spindle Kick Starter End Play @ .0575”, Shaft Main Transmission End Play @ .028” (I was told on a previous posting that these #’s were OK). Replaced Clutch Cable (new) in-case binding under pressure – No Change
- Replaced NAPA 30w oil with Spectro Golden 4 10w40 – No Change
- Removed Clutch Friction/Steel Plates, Stopper Rings (2), and Clutch Hub. Washed Friction Disks (5) with brake cleaner, cleaned Steel Plates with Scotch Bright pads, Checked both for flatness Ok.
Measured:
Friction Disk Thickness: 3.70mm – 3.77mm (0.145 – 0.148) Backing Plate Thickness 3.32mm Contact Width: 13.5mm (0.531)
Beveled “A” Steel Plate Thickness: 2.99mm (0.117)
Steel “B” Plate Thickness: 1.59mm (0.0625)
Springs (Blue ends): 34.34mm (1.352) Long, 18.78mm (0.739) OD, 13.50mm (0.5315) ID, 2.61mm (0.1027) Wire diameter
Wire Spacers (Stopper Rings): 0.60mm
Used flat India stone to remove minor wear ridges on hub
Reinstalled Clutch “A” Plate (bevel towards engine)/SR/F/”B”/SR/F/”B”/F/”B”/F/”B”/F/ Pressure Plate, Torque Spring Bolts to 120 In-lbs, Reinstall Left Case cover and fill with NAPA 30w ND – No Change
The one thing I did not do was to put the Dial Indicator on the Pressure Plate and measure the lift when the lever is pulled, visually it looked OK but I should have measured it (how much should it be?). Also, I seem to remember a slight amount of sideways movement on either the Inner Hub or the Outer Basket (I don’t remember which) when I had the plates removed but again I forgot to measure it.
So… any suggestions on what else might be causing my dragging clutch? The engine also has low compression (125-130 lbs) so it looks like I’ll pull it for the winter and do a full engine/transmission rebuild.
Thanks for any thoughts/suggestions.
tnx
George
’68 CA77 Dragging Clutch… What did I Miss?
george; sometimes the clutch springs can get off center in the holes in the clutch center and can drag. this will cause the clutch to be heavy and not release completely. it would be a better set up if the spring mount washers had a dimple to aid in centering (like a lot of other engines) but they don't so you need to be carefull assembling that clutch.
good luck Randy
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