Our tip for working on Vespa and Lambretta engines
Precise work when building a new engine is essential for a good result. Intake angles for rotary valve or piston-controlled engines, as well as the overflow and exhaust angles of the cylinder are important key data that must be taken into account when building an engine. Nowadays, depending on the choice of components, it is not uncommon for the cylinder and/or the engine housing to have to be subsequently machined in order to achieve the desired control angles in the intake area and in the cylinder. In some cases, this cannot be achieved simply by measuring with a caliper gauge. It is therefore advisable to assemble the engine "dry" in order to determine the required dimensions. However, if the motor housing is to be machined afterwards, ball bearings that have already been inserted would have to be removed. In almost all cases, however, this would mean the premature death of the sensitive bearings.
NEW: Bearing dummies
So-called bearing dummies provide a remedy here - a great neologism, although the German description
"Ringeinsatz zur Simulation eines Kugellagers"
(ring insert to simulate a ball bearing) would probably not roll off the tongue any easier...
Advantages of "ring inserts to simulate a ball bearing"
The dummy can be inserted into the motor housing without the usual shrinking procedure.
Like the ball bearings, the dummies are provided with clear chamfers for easy installation and removal.
The crankshaft can be rotated freely in the dummies and it is therefore even possible to determine the crush dimension. Useful aids for collecting this important data are also, for example, the bgm degree disc in conjunction with the whale. With this combination, all necessary steering angles can be precisely determined without any problems.
Once all the data has been collected by using the bearing dummies, the replacement
ball bearings can
be easily removed from the engine housing.
It's all about the right size!
We have now developed the bgm PRO bearing dummies.
MADE IN GERMANYThe bearings are available in all important sizes. In addition to the dimensions of the corresponding ball bearings, the bearing designations can also be found in the designation of the dummies. The size is specified as follows (for example, the bearing dummy for the alternator bearing of the Vespa PX and PK ETS): Bearing dummy crankshaft -BGM PRO- NBI 253815 (25x38x15mm)
- NBI 253815 = Bearing designation of the manufacturer (Nadella, SKF, etc.)
- 25 = Inner diameter of the bearing in millimeters
- 38 = Outer diameter of the bearing in millimeters
- 15 = Width of the bearing in millimeters
All sizes available:
The different combinations according to scooter type:
You therefore need different dummies for different combinations of engines and crankshafts.
Vespa Sprint 2-channel
- Drive side BGM1200TL; bearing dummy crankshaft -BGM PRO- 613912 (25x62x12mm)
- Ignition side BGM1200TL; Bearing dummy crankshaft -BGM PRO- 613912 (25x62x12mm)
Vespa T5
- Drive side BGM1200TL; Bearing dummy crankshaft -BGM PRO- 613912 (25x62x12mm)
- Ignition side BGM1205TL; Bearing dummy crankshaft -BGM PRO- N205, NU205, 6205 (25x52x15mm)
Vespa PK 50 with conversion to ETS crankshaft
- Drive side BGM1203TL; Bearing dummy crankshaft -BGM PRO- 6303 (17x47x14mm)
- Ignition side BGM1207TL; Bearing dummy crankshaft -BGM PRO- conversion to PK ETS bearing (25x47x12mm)
Lambretta GP
- Drive side BGM1204TL; Bearing dummy crankshaft -BGM PRO- 6305 (62x25x17mm)
- Ignition side BGM1206TL; Bearing dummy crankshaft -BGM PRO- NU2205 (25x52x18mm)
Plastic bearing dummy
This allows the crankshaft to be mounted and moved in the engine housing on a trial basis without the need for force. This means that neither the crankshaft nor new bearings are stressed for purely measuring purposes. Ideal for checking the control angle of the crankshaft (rotary valve intake) or the cylinder (exhaust angle, overcurrent angle).
Made in GermanyThe bearing dummies from bgm PRO are available from the Scooter Center Scootershop: [su_button url="https://www.scooter-center.com/de/all/search?query=lagerdummy&catalog=true" background="#d40e14" size="10" center="yes" icon="icon: circle"] Stock dummies CMD[/su_button]
DE | €
