Tail suspension quick question

[kokis]

I never touched tail spring and clicking-screw.
Sometimes when I ride with passenger(depends on her weight) I feel that bike is more stable and ride is more comfortable. It has something to do with suspension.
What should I do? Tighten up spring or lose it? Or just adjust clicking-screw?

[manwithgun]

There are too many variables and unknowns to properly answer this question.   The good news is that with a few simple hand tools and some research,  you should be able find a setting that suits you better, though it is often a game of give and take.  When you look at this from a geometry stand point, having a passenger perched on the tail of the bike adds weight, which compresses the rear suspension and lowers the rear of the bike.  This changes the rake and trail of the front end which affects handling.  One approach is to soften the rear spring by removing preload (loosening the collar) for solo rides but this may not be the proper method. Correct spring rate is determined by total rider weight and confirmed and fine tuned with static and free sag measurements.   Assuming that the your spring rates and sag are correct for solo riding,  You can achieve similar bike geometry by either lowering the rear or raising the front.  Most Ducatis have a rear ride height adjuster while the front is changed by moving the forks in the clamps.  Spring rates, preload, static and free sag, rake, trail, etc... They all make a difference and we haven't even mentioned the clickers yet.   That's all I've got for now.  Update your post with more information regarding bike model and mods, as well as rider weights and you may get more help from the board.

One thing to consider is that it may not be the bike at all.   It might be something in your body position or input into the bike that is making the biggest difference.  Riding solo may allow you to "try" to hang off of the bike, putting too much weight into your arms rather than core.   Do you ride more upright with your knees locked to the tank while riding with a passenger? 

btw, my post is based on my opinion.  I'll let the rest of you sort out the right from the wrong. 

[kokis]

Well, thanks for big reply.
It is M696. Spring fixed right in the middle position. I have carbon termis, rizoma short tail, even carbon back wheel shroud. So it noticeable weight reduction. My weight is 90kilo with all gear.
My suspension back and front is very sensetive. At acceleration it always pushes me back at even light brakes it pushes me front. I can't say I grip to tank with knees too much i am very tall and it is not comfortable, i do it mostly while turning cornering.

Before annoying everyone with stupid topic I red suspension adjustments manuals on internet. They are sort of hard to figure out for newbie.

[scooterd145]

Why not just explore? No one can really tell you how to put it so it feels right for you. Go out and mark where the collars are now on the spring. Crank it either softer or harder several clicks and go ride it. Did it get better or worse feeling? You either went the right way or the wrong way...

Prolly the best way though is to have someone help you set the "SAG" first or take it to a shop that does setups. Be sure to wear your "normal" riding gear for the additional weight. I got mine done locally for $25 and it included some recomendations. I have fine tuned it over time for the way I like how it feels for me.

Scott

[Howie]

First get the basic setting correct, adjust pre-load to a spring length of 150 mm + 1mm. and 8 clicks on damping.  Then adjust pre-load for proper sag with you and your gear on the bike.  I do not know an official Ducati spec, but typical for a street bike is 30-35mm. from unladen.  Can't get sag correct you need a different spring.  If you don't carry passengers a linear spring of proper rating is a good idea anyway.  You will need either two helpers (one to hold the bike and one to measure) or or a wheel vise and a helper.  Lots of tutorials for this on the internet