I've been noticing that my bike hasn't felt very set the last couple times I've ridden it, not sure if it's something new, or just something I just noticed, but there's quite a bit of instability in the front end, especially through turns...how much of this is normal?

Also, does anybody set the rear spring preload up higher when riding by themselves? What do you set it to?

I don't think any wiggle is normal if the road surface is smooth.

Check tire pressure, alignment, head bearings (put it on center stand with a friend sitting on the back, grab the forks at the axle and push/pull).

I have mine set to 6 and I'm about 206lbs. Feels perfect for me.

Paulcet ... you're running a  Kat FE ... a GS front end is made of much lower components.
Secondhand - what you mean by wiggle ?
I have routinely had fork flex on many many bikes, all cruisers literally flex almost perceptibly. GS stock suspensions flex a good bit under braking. That is even with Progressives, or any other ... in some ways cutting down in travel causes the forks to act less stiff, they stay more extended, so they are longer, and the stiffness is dependent on the cube of the length. You stay without compressing, it will flex to the left more, aka away from the caliper. If it compresses it will be stiffer and deviate to the left less.
Twin discs let it flex straight back, and not side to side, and cruisers with 1 disc and looong ass front suspensions literally feel like you're making a pretzel.
If you have all the components cinched down to the right torque, and still flexing, its prolly part of your bike's "quirks"
Cool.
Buddha.

Up to a few months ago several folks were flogging fork braces a bit more substantial than the joke that is holding the fender up from the factory. Drop fork brace in the search to see pretty pictures, though I didn't see any newer than January or so. Easy enough to make if you are at all handy. I'm thinking I might grind up a section of old truck spring I have, or some other hunk of metal that's not absurdly flimsy.

I have a few made from 7075 a few years ago. $40 and shipping.
Heck I should put it up for sale.
Cool.
Buddha.

Yeah, Buddha's right, not much flex in the Kat FE.  I have an old Yamaha YX600 that flexed a little, but no "wiggle".  Upgraded head bearings, too.

Also stiffness depends on cube of the diameter. You double the diameter and you instantly get a 8X boost to stiffness. A kat's 41mm is ~11% larger and will probably be over 33% stiffer. And to that add that it does not twist and the difference is huge. Somehow a Kat FE on GS literally ... just feels right. The GS actually has a better frame than a katana. That incongruence actually makes the GS frame the right one for a Kat FE.
Cool.
Buddha.

Been riding over tar strips on a sunny day?  That's about the only time I can think of my front end feeling anything less than stable--aside from cinders. 

I ended up buying a Whole katana for the front end, there pretty rare to be broken anyways , i spent 200 pounds , which i had made profit on a r6 tail, so i got it basicly for free , so i had this whole katana , it felt heavy , and crap , to took the bits i wanted ,

Front end , seats *which ended up on mini motos*  had a new battery in it , wheels , swingarm , M/c's

Sold the rest for a lil more than 200 quid on ebay,

so i got new tires , *until the 4.5 inch wheel i got , a Complete Katana fe with progressives , for free

and my Gs has never felt better, my fav upgrade

Too much of anything can be a problem, but my girlfriend has a bit of this and it works for me.

Jay_wolf and other kat FE users - I have several GS FE's lying about, and seen several on other people's bikes. The kat FE's same thing. Now somehow even the better maintained and regularly used GS FE's tend to rust more and get other blemishes more than the Kat FE's ... even ones that were neglected. Does that seem to parallel your experience or am I the only one. Even kat's that were lying face down in the dirt in the junkyard seem to have forks better than the good GS ones.
Cool.
Buddha.

Quote from: the mole on August 11, 2008, 04:26:39 AM
Too much of anything can be a problem, but my girlfriend has a bit of this and it works for me.

i agree but it is my wife not girlfriend. Although I think I could stand a little more front end wiggle.

I get some wobble but only at around 40 mph, little bit of headshake but I also need a new front tire.

Quote from: b_long_1 on August 11, 2008, 11:28:58 PM
Although I think I could stand a little more front end wiggle.

Couldn't we all

Does it get worse when you apply the brake. if so its probably a warped rotor, if not I would guess tire, the only wiggle I get is at about 85 or above.  And rear is all the way to 7 buy then again Im 260lbs and like a stiffer suspension.

Chanse - A warped rotor (or a rotor with a few thin spots) will make a pulsing feel at the lever. A warped rotor usually will have visible grooves in it and will likely break or scare you 1/2 to death.
Under braking bike wanting to go left is FE twisting, all others ... no idea, tires, alignment neck bearings ... what ever.
260 lbs Yea, you're definetly over 2 X the bike's nominal cargo design weight. I am also close to that. All I'd say is ... Kat FE.
Cool.
Buddha.