As part of our Platonika project, which we are putting together with Maryzabel, we are preparing many important assembly steps as tutorials in videos. Our first tutorial shows the important differences between the various types of stud bolts and the correct installation. Common questions such as:
Which side is screwed into the engine casing? or
Is the stud bolt glued?
are answered in this Vespa Tutorial. In the Vespa area, the threads of the original stud bolts have a "thick" and a "thin" side. On the thin side, the thread is shorter, and on the thick side, it is longer.
The side with the thicker thread is screwed into the engine casing and, as long as the engine casing is intact, it will hold by itself. The stud bolt is therefore secured against loosening on its own. The free length left over the engine casing is determined by the cylinder and cylinder head.
Different Variants
Besides the various thread lengths, there are other characteristics for distinction. Here are the most common ones:
-Rounded End or Step
If one end of a stud bolt is rounded or has a distinct step, and the other end is flat, the rounded side points toward the cylinder head, and the flat end is screwed into the engine casing. Stud bolts with a step also make the installation of washers and nuts in the cylinder head easier later on. Stud Bolt Set -M7 x 140mm
-Marking on the Shaft
On one side of the stud bolt, below the thread, there is a ring-shaped marking. The marked side points toward the cylinder head, and the side without a marking is screwed into the engine casing. Stud Bolt -M8 x 160mm
-Impact or Dot Marking on the End Face
If one end face of the stud bolt is marked, such as a dot, star, or a type of cross, then this is the free side of the stud bolt, and the opposite end is screwed into the casing. Stud Bolt -M7 x 59mm- 22-17-20mm
-Fixed Thread Lock
Stud bolts with manufacturer-applied thread lock are easily identifiable by the material. The side with the thread lock, clearly visible in blue, green, or red, is screwed into the engine casing. The free side is clean, without any lock application. Stud Bolt -M8 x 165mm
-Special Cases
An example is stud bolts that have a clearly marked side but the mounting side for the engine casing does not have a thicker thread. These stud bolts should be installed with thread lock. Stud Bolt Set -M7 x 158mm
Installing Stud Bolts on Vespa Engines
To securely install the stud bolts, we offer this simple yet brilliant Stud Bolt Installation Set. This ensures that the stud bolt is securely fixed when screwed in and cannot rotate freely, as often happens with two countered nuts. Stud Bolt Installation Tool Set -BGM PRO- M6/M7/M8
Vespa Platónika
Platónika is the name of the scooter. A Vespa PX that we are completely rebuilding with new parts from the Scooter Center warehouse. Of course, we use our best BGM parts. Benefit from our know-how, receive many tips, and take a look behind the scenes. Follow the project here in the Scooter Center Blog.
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