Setting Clutch Preload on a Sachs
One of the problems commonly found in Sachs engines is the oft misunderstood clutch system. The clutch is basically maintenance free, but in some cases the pre-load must be adjusted. This may be due to old friction material swelling up, or tampering by a previous owner.
Improper clutch pre-load can cause:
1. Stalling at stops.
2. Rear wheel spinning while idling on stand.
It is important to make sure that your carburetor is clean and in good working order with the idle speed properly set before continuing as too fast or too slow of an idle can cause either of the above symptoms.
Start by putting a pan under the engine to catch any fluids in the transmission. Then disassemble the starter clutch as follows:
1. Remove the 5 screws holding the clutch cover on the side of the engine
2. Remove the long screw from the top of the clutch housing observing the position of the clutch arm, spring and cable.
3. Pull off the starter clutch bell.
You now have access to the clutch.
The clutch plates should have .4mm - .6mm of play (.016 - .024) You can check this by trying to push th clutch plated back and using feeler gauges to measure the gap left between the clutch nut and the shim washers, or between the shim washers and the clutch plate.
If there is too much of a gap, you will want to add shims, if the gap is too little or nonexistent you will need to remove shims. You will first need to remove the clutch nut (immobilize the crank by whatever method you see fit). Then remove the little rectangular spacer, under that should be some thin washers, these are the shim washers. Remove or add enough shim thickness to accomplish the desired play. You may need to order some shims to complete this. When reinstalling the clutch nut clean it of all oils and torque it to 25.3 - 28.9 ft/lbs. This is a lot of torque to put on that, so any grease, oil or transmission fluid on the threads could easily allow you to break or strip something. A little locktite would be a good idea.