shock spring tension

Hi I’m a 120 kg lump but the suspension is way too firm. Is there a secret to undoing rear spring , it feels like the spring has so much load on it that the nut wants to gall on the threads. I’ve separated the lock ring.
And how do you set the amount of drop when you sit on it?
I’d be reasonably confident it’s the stock suspension.
Thanks

The stock spring is too weak, not too stiff, especially for those of us of more, errr? 'Ample' proportions. The stock Sachs is under sprung and over damped, poorly! If you look at the bump stop I'll bet you it's being beaten to pieces, (If it's still there!). Increasing the preload won't make it less harsh or prevent it bottoming out. Simply make it take more effort to start it moving.

The stock shock is pretty rubbish. If you can't replace it at least re-spring it.

Totally agree with Pete
And it is the rubber bump stop that feels like stiff suspension.

I weigh 105Kg in helmet and jacket and on mine i found the standard spring was almost completely collapsed so any bumps were immediately compressing the rubber bump stop.

Going up to a 13Kg/mm spring from the standard (I think 9.9Kg/mm) has improved the suspension massively.

Now it is sitting in the top 1/3 of the spring range i find the Stelvio shock a little bit too tall (I am 5ft9in with a 29in inside leg) so i am using the standard shock til i can afford a proper one.

i also agree with Pete. At 325# I was bottoming out often. A new shock/spring made a world of difference. It was expensive, but worth every penny.

Pete Roper wrote:

The stock spring is too weak, not too stiff, especially for those of us of more, errr? 'Ample' proportions. The stock Sachs is under sprung and over damped, poorly! If you look at the bump stop I'll bet you it's being beaten to pieces, (If it's still there!). Increasing the preload won't make it less harsh or prevent it bottoming out. Simply make it take more effort to start it moving.

The stock shock is pretty rubbish. If you can't replace it at least re-spring it.

Based on earlier discussions on this same topic, and Pete's recommendation, I changed out the stock spring to a Hyperpro spring #1224.   Hyperpro doesn't list the GRiSO on their website, but it's the same spring for other Guzzi models.  

Huge difference.  Costs $130 approx, get it installed and then have sag and rebound properly set with you on the bike in gear.  You will find this makes a massive positive difference in the ride and handling and turn in capabilities of the GRiSO.