Modern Vespa

I know this subject has been beat to death. I searched the forum for examples of this fairly common machine and equipment mod.
In the case of the GTS front end wobble it might help/improve the characteristic wobble and lack of dampening at the steering head .
In other machines and equipment utilizing enclosed shafts for slow speed applications the addition of grease to the shaft housing greatly dampens the transmission of minor vibrations.
A similar example is automotive split driveshafts, steering columns at the telescopic spline (my Toyota Sienna) and hand controls on machine shop equipment.
I thought I might try adding a remote grease fitting to the steering shaft housing on my GTS. I have no problem removing plastics to access the area of the steering head and adding a grease fitting. It could be extended to be accessed in the glove box or behind the front horn cover
Heavier non synthetic wheel bearing grease could be pumped in till it reaches both bearings.
Head bearings should be at proper torque, weighted bar ends, quality front tire, good front shock setup, etc.
I will probably drill a 1/16" hole at the head tube with a slight countersink and use a needle tip on my grease gun.
Just throwing this out there. Maybe it's an idea that will help???
Comments....... Go easy on me; I'm usually not a hack but I'll try anything that might work in this case.

I would suggest that you disassemble the bike and have a look at how the bearings are situated on the fork and how they are serviced.

I might dig in today. Check torque on bearings and pack with grease to start.
I just bought the scoot yesterday. Only 2700 miles but needs the usual.
Do you know if they're caged bearings or free.

Looking at the parts manual here , they look like cage

https://manuals.wotmeworry.org.uk/Vespa/GTS250/GTS250%20Parts%20Diagrams.pdf

Link taken from our wiki link at top left of page , if I have selected the wrong version for your bike 👍

TY. Parts manual is a big help.
I just saved it. Nothing worse than flying blind.
I think, as many have said, that everything you do up front works in conjunction to eliminate that "worn in" condition that we experience on these scooters.
By nature, bearings shed grease/lube. Before I buy a tire or shock absorber we'll see how it behaves with freshly packed bearings and proper torque.

they're caged.

there's nothing really to pack, so to speak. you'll see when you get there.

what do you mean "needs the usual"? at 2700mi that's practically brand new.

Yes. When I get into it we'll see how lube plays into this. If the cavity can be packed with grease that may act as a damper but won't know till I'm in there. I don't have high expectations but???
For the usual it is a 2009 so some age on it - cooling system service, brake flush, ck rollers and clean variator/belt, fuel pump HAS been replaced. I usually go down the list of service items in manual and try to do everything practical.
This was a well cared for scooter that was used every year. It never sat in storage. Shouldn't be too needy.
Unfortunately I can't ride as much anymore but I like the work and I will sell with confidence when the time comes

Steering head preload very loose. Close to Zero (0) ft. lbs. torque. And this is a 2700 mile scooter !! This should account for most wobble. I packed the cavity with red sticky grease. That might dampen some??
Can't drive it today - rain.

Steering pre-load is intended to be near zero. The outer tube heats up more than the inner tube on a hot ride, which adds pre-load. This was a well-known steering bearing 'notch' cause in many Piaggio bikes that have tapered roller bearings - but seems to have been forgotten over time. It also applies to the ball-bearing steering bearings, but to a lesser extent.

On the X9 series for instance, a service bulletin came out that required a 90 degree back-off of the lower ring after applying 2Nm of torque.

GTS fitted with a sidecar are well known for an exaggerated version of the dreaded steering wobble. Texas Sidecars (maker of the Via sidecar for the GTS) used to recommend tightening the large nut at the top of the headset. Increasing the friction in this way substantially dampened the tendency to wobble. A number of sidecar motorcycles have been fitted with an adjustable steering damper that essentually does the same thing.

I made a quick tool to torque. 12-14 nm is spec I torqued to about 15-16 then backed off. . Right at my mark the first time. Good guess huh.
It was probably at a tick over 0 originally.
We'll see how it goes

wow. well, it certainly is a different approach.

After setting torque to factory spec 14nm and removing rear case - haven't noticed as much wobble. Tried different speeds and deceleration. Steering is still kind of funky on these big scooters with little tires.
Don't know if grease packing helped but it couldn't hurt. Grease will eventually migrate to lower bearing which at 2700 miles I did not remove.
Next it's on to tires. There's a newer Michelin Power Pure in back and I'd like to match that in front.
Opinions??

I had Power Pures on an Aprilia SportCity 300 several years ago. They are a good tire, but do not wear as well as the Michelin City Grips in my experience. As I understand it, the Power Pure is supposed to use two different rubber compounds and produces improved traction. I couldn't really tell the difference and have used City Grip tires on both of my GTS.

TY I think I will try the power pure. I won't put enough miles on them to wear them out.