I have a completely stock 1980 Sachs Suburban with 800 miles that's in great shape, but stalls at stops. I know this is a common problem and I know it can usually be sourced to the clutch. I have had the clutch apart dozens of times with different shims and different parts from two sets of clutches and here's what I've found out:
- With a 0.80mm shim, the bike goes 30 mph as it should, but stalls when I stop. With this setup, I have around 0.2mm of preload. Play at the starter lever is within spec at 1mm and the screw on the clutch arm is turned 1/4 out from touching.
- With a 0.60mm shim, the bike goes 28 mph and stills stalls at stops. Preload is within spec.
- With a 0.40mm shim, the bikes goes 28 mph and stills stalls. Preload is still within spec.
All of this leads me to believe that the clutch isn't my problem, but rather that the bike isn't idling low enough. The bike runs great, although the idle does sound a little off to me and also a little choppy. Any attempt to lower the idle anymore kills the bike. The plug is a nice brown color, plug gap is fine, timing is fine, air filter is new, gas is fresh, carb is stock square bing with the stock jet, no air leaks that I can find with carb cleaner, and the bike behaves the same with an ebay carburetor. The carb does appear to leak gas from the bowl or elsewhere, but I can't find an air leak around there. Maybe the float level is too high? Would that not allow the bike to idle lower? Here's a video of it idling and stalling with the 0.60mm shim. Does the idle sound right to you? I don't have experience with how a two-stroke should sound and idle.
I've run out of ideas and need some different perspectives on this, so if you have any input it would be greatly appreciated, thanks.