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MG Midget and Sprite Technical - RPM drops

When I press the clutch pedal the motor drops by 200 RPM. Is this normal?
Flip
Flip Brühl

I would say it's not normal but it's very common. One possible cause is wear on the crankshaft thrust bearing allowing the crankshaft to be pushed forward when the clutch is pressed. Get someone to closely watch the front pulley when you press the pedal and see if any movement can be seen.
Mike Howlett

A worn out clutch release thrust bearing will also do this. Once the carbon has gone the bearing is steel on steel without lubricant. You might hear a horrible noise but not always. I have a roller bearing now and it's the best thing I ever did.

Les
L B Rose

In an ideal situation it should not occur.
If however no strange sounds are heard and the the crank damper does not visibly move fwd when the clutch is depressed best to let it be.
I can think of several harmless reasons certainly where non standard camshafts and lighter flywhees are used.
O K

Recently I changed the ball bearing for a carbon one as I did not have a ball bering with the right dimensions. And yes the flywheel is 30% lighter. I ll inform you if the crank damper moves forward.
Flip Brühl

The damper does not move, so it is the carbon bearing
Flip Brühl

That is a big jump to conclusion ;)
O K

This thread was discussed between 10/09/2018 and 11/09/2018

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