OEM Suspension setup?

[crimson04]

I have the concern with 2 up on this bike. I weigh the 180 and she around 160. With 2 on the bike it handles like garbage.I know the front forks need to be stiffened substantially.

[pattonme]

shock is probably the bigger problem when there are 340lbs sitting on it. weak forks don't help, for sure

[2whltuner]

IMHO, just as with setting up the "sag" with a solo rider, the same needs to be done with two up to the same sag as with the "solo" rider set up. This may or may not max out your "spring preload" on the shock and the forks. Should you "max out your spring preload" a stiffer spring(s) will be required, and as with more spring, more rebound will be required to control the spring, this again may "max out" your available rebound adjustments.

[2whltuner]

Went to set my rear suspension sag with my girlfriend, (215lbs/135lbs) aiming for the 43mm of rear sag same as solo. Unable to meet sag do to the limit of the rear preload adjuster. At 7/7 on the ramp, I was still 16mm short of my intended target, (is 59mm sag s/b 43mm sag) (520mm unloaded 461mm loaded)and this is even without the saddlebags and those damn heavy saddlebag supports. I am going to either pony up for the Penske, check out what Nitron has, see what Race Tech offers (they state complete RG3 Shocks [lesser of all evils]), not really interested in Ohlins (what's up with all those shock failures on oem ducati's, yamaha's and Hondas)

[pattonme]

I think Ohlins is cutting corners on supplier quality lest they get priced out of contention - OEM deals are like supplying to Walmart, you get screwed to the wall to minimize price in the hopes you "make the losses up on volume". (or somebody lied to win sub-component bids)
 
On another thread I think I came up with a rule of thumb that went something like, 30% stiffer spring for every 100lbs over 200 in load. Consult the shock supplier, but it should get you in the ball park.

[jimf]

I have the concern with 2 up on this bike. I weigh the 180 and she around 160. With 2 on the bike it handles like garbage.I know the front forks need to be stiffened substantially.

With the stock spring on there you'll want to max out the preload on the rear for sure, when riding 2-up.  That will matter a lot more than anything you do to the front.  Even so, I wouldn't expect miracles on the handling front no matter what you do.  Rebound damping is going to need to be run up to close to the maximum as well, otherwise the bike is all over the place if it gets rough in a corner. 
I tend to like the front to be a bit soft when running heavy, if only because I'm probably going a long way and appreciate the comfort, but YMMV.  Interestingly the harsh compression damping I feel when the bike is unloaded on bumpy roads is pretty much gone when the bike is heavy.  Yamaha's setup seems schizophrenic to me, with some settings appropriate for touring and others for sport, although I have to say that the stock suspension is quite a lot closer to what I want than most of the OEM Japanese bike setups I've dealt with.  Some of them are horrible to the point of wondering if they even tried at all.
 
It's funny, while I think about the suspension regularly when riding solo I never give it a second thought when I ride with my daughter on the back.  We just get on and go.  When I'm riding two up I'm not going to go bombing around: It's ok for me to risk myself but not ok for me to put her at risk.  Riding around at two tenths makes the suspension and handling matter a lot less than when I'm out touring and find a great mountain road and run right to the edges of the tires, giggling and screaming "WHEEE!" into my helmet. :-)
 

[estell]

OEM Suspension Set-Up 
Weight w/o gear 217lbs, no saddlebags installed.
 
Fr. Sag 45mm (9mm of preload adjuster showing as illustrated on page 4-31 of the owners manual)
Fr. Rebound 6 out from full hard
 
Rr. Sag 43mm (3 out of 7 on the rear shock preload adjuster)
Rr. Rebound 1-1/8 turns out
 
Taunt suspension but works for me until I decide to pony up the dollars for the cartridges and Penske.
 

Thanks for posting those suspension settings. Your sag measurements target 33% of the suspension travel. My weight matches yours so I copied your preload and rebound settings. Went for a ride and had much less dive on hard braking than I had been getting with the factory setting. 
Worked well enough that I practiced hard stops. Got some ABS action on the rear but not on the front.