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Jeff NJ Jeff NJ is offline
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Join Date: Nov 2013
Location: NW NJ
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Originally Posted by gsxrken View Post
Ahh... sorry for any confusion, Jeff.
In that case, I imagine the aftermarket manufacturer should specify what the distance from the flywheel surface out to the throwout bearing ears must be, to avert this very scenario.
Dropping an engine is mentally much harder to do than it is physically, and I don't say that to trivialize it. I would be swearing in the general direction of the aftermarket right now.
While these aren't OEM parts, they are practically off the shelf parts as this has been done hundreds of times by Chris C himself and I am sure Sachs has made thousands of them. Not that it can't be a problem as Jake has correctly pointed out, only that this is not some one-off custom job. It is the stock specs for the 76-77 930 PP (but aluminum) and a spacer ring to make up for the shorter PP (easy to measure since I can just stack them and measure against the original) and the TO extension should be the same amount longer than the original as the spacer ring is. The actual TO bearing is the OEM one (just the collar with the extension is not OEM), the needle bearing is the OEM one, the friction disc fits all 930's from 78-88. It is designed to just drop in with those two changes (spacer and TO extension).

The more I think about it (not getting much work done today), even if the spacer or TO extension were out of spec length-wise, because the fork position is infinitely adjustable with the cable and levers, when you pull the cable 25mm, it will still pull the TO bearing away from the friction disc the correct amount, so neither of these specs should matter. Now, if the PP was defective where the pulling the TO bearing out the correct distance did not cause the pressure plate to back away from the friction disc enough, then that would be an issue. I really didn't pay much attention to how that assy actually works, but I will be if I open it up.

If the TO bearing travel is say 8mm (for example) when the cable is pulled 25mm, how far back is the PP supposed to pull off the friction disc? It is spring loaded, so it probably isn't the same 8mm. Maybe it is 4mm, which gives enough clearance that no power is being transmitted to the friction disc. What if the diaphragm is assembled incorrectly, or something else is wrong and it only pulls back 2mm? enough to let it slip, but still drive the wheels like mine are being driven with the clutch in... Just another scenario I have to consider if I pull the motor. I can clearly see through the inspection hole that the diaphragm splines are moving considerably toward the transmission when the clutch pedal is depressed fully, so that tells me that the cable, levers, fork, and the TO assy is moving correctly, but I cannot see how far back the actual surface of the PP is moving away from the friction disc without pulling the motor.

Anyone have the specs as to how far back the TO bearing goes when the clutch cable pulls the spec 25mm? And how far back is that supposed to move the PP surface? I would think that the stock clutch should have the same specs as my new one.
1988 930 Venetian Blue

Last edited by Jeff NJ; 05-15-2015 at 12:41 PM..
Old 05-15-2015, 12:38 PM
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