Scooter Repair Tips
Got Any Tips? or you would like to know anything "How to do it?"
let me know and i will put it on here for you (All Vespa's Only)
Servicing Specifications and Lubricants for Vespa's
Vespa GT125/200 and GTS
Tyre Pressure Front 26psi / Rear 29psi with Passenger 32psi
Spark Plug 125cc NGK CR 8EB / 200cc Champion RG6YC
Engine oil type SAE 5W40 synthetic oil
Vespa 1978 to 1995 P/PX 125,150 & 200 including T5
Tyre Pressure Front 17.6psi / Rear 25.8psi with Passenger 36.7psi
(Tyre Pressure T5 Front 17.6psi / Rear 24.9psi with Passenger 35.5psi )
Spark Plug 125cc NGK B7HS /150cc B7HS/ 200cc B7HS
(T5 Bosch W3 CC or Champion N-2C)
Gearbox oil type SAE 30 oil
I DO HAVE Haynes Manuals COVERING VESPA FROM :
1959 TO 1978
Models v9a1 Vespa 90 /v9ss1 Vespa 90 Super Sport / v9ss2 Racer /232L2 124cc/
vma1 121.1 cc Vespa 125 / vma2 121.1 Primavera / 312L2 145.45cc Sportique /
vbc1 145.45cc Vespa Super/ vLa1 145.45cc Vespa GL /vlb1 145.45 Vespa Sprint /
vsd1 180.69cc Rally / vse1 197.97cc Rally 200 Electronic...
1978 TO 1995
P/PX125,150 & 200 Including T5..
1996 TO 2006
VESPA ET2, ET4, LX & GT
PLUS PIAGGIO
1996 TO 2006
SFERA,TYPHOON,ZIP,FLY,SKIPPER,HEXAGON,LIBERTY,NRG,B125,X8 & X9..
Vespa GT200
Here are a few photo's showing how I reached the Spark Plug. It took me all of 10 mins to change the plug. It's not very difficult to reach it, and you can't see the plug at all, just the plug boot and wire. Removing the plug itself is by feel. It is also a good idea to use some compressed air to blow away any dirt and debris out of the SP recess after you remove the plug boot. That way nothing will fall into the cylinder after the plug is removed. 
Just reach around the cylinder head and grab hold of the boot, pull if off. 
My finger is on the wire/boot. When you pull it off (it may take some wiggling) don't pull on the wire itself, grab a hold of the boot. 
Use the plug wrench from the Vespa tool kit, it is much easier and was made to get into this tight spot, the open end wrench works best too.