Owned and rode many miles on a G5 & SP1000.
Helped my Cousin with a super major service on his loop-frame 15 years ago.
The wheel seals were blue rubber and reused, as were the Timkin wheel bearings.
For its build date, it just ozzes quality. imo
Some guys would use special 3/8" thick valve cover gaskets to gain clearance inorder to line the inside of the cover with 3/8" cork sheet... to quiet the valve gear.
If Guzzi valves are set too tight, the engine will not idle down when hot. I know.
The Tonti framed engines have a 14# flywheel w/o the twin disc Sachs clutch installed. The loop-frame flywheel is 36#. Much heavier than the old VW flywheel.
Super fun ride. N-Joy.