Does anyone know how the exhaust decompression gizmo on the exhaust camshafts works?

I've not had the cam box off yet, [ but will be doing soon to re-shim ] so I've only seen photos of what look like bob-weights on the shafts, but can't figue out how they would work.

I presume they only activate while cranking the engine to start, but that's a guess.

Anyone know for sure?

Yup....
Think of a round pin that has a flat ground on it.
Mount this pin in a plate that can rotate the pin.
Orientate this pin so that the round side can ever so lightly depresss one exhaust valve while the piston is ascending.
Now, lets put some spring loaded weights that swing out as the camshaft spins with the engine running. The pin is then rotated to the flat side, so it doesn't depress the valve anymore. Eventually the springs get a little tired, and you will hear the assembly ticking. But it's nothing to worry about.

 

Tx TLR!
I did the reshim job and saw the decompression gizmo in the flesh. Clever!

Mind, I'm not that happy about the tiny return spring whizzing around. That looks like an accident waiting to happen. I would have taken the whole thing off if I could figure how to do it without destroying it completely!

Tx for the come back,

WW

 

Tx TLR!
I did the reshim job and saw the decompression gizmo in the flesh. Clever!

Mind, I'm not that happy about the tiny return spring whizzing around. That looks like an accident waiting to happen. I would have taken the whole thing off if I could figure how to do it without destroying it completely!

Tx for the come back,

WW

Removing them requires some machine shop work, or a little tender loving care with a hand held grinder. Battery and starter doesn't seem to be affected when they are defeated.

 

Tx TLR. I was wondering about the effect of the extra load on the starter,

Cheers, M8,

WW