primary translation BGM PRO without clutch basket, 64T, 21/64 (3.05) for Vespa V50, PV125, ET3, PK50, PK80, PK125 BGM06421P fitting for Vespa PK 50 V5X3T 1994, 2,7 PS, 2 kw

PRIMARY (without clutch basket) BGM PRO VESPA SMALLFRAME V50/PV/ET3/PK

Primary wheel BGM PRO 64 teeth
Matching BGM PRO primary sprockets 19-20-21-22 teeth
This results in primary reduction ratios of: 3.37 (19/64) - 3.20 (20/64) - 3.05 (21/64) - 2.91 (22/64)

Primary wheel BGM PRO 65 teeth
Matching BGM PRO primary pinion 25-26 teeth
This results in primary reduction ratios of: 2.60 (25/65) - 2.50 (26/65)

ADVANTAGE BGM PRO PRIMARY
This means that a wide range of reduction ratios can be realized with the installation of a BGM PRO primary wheel. Only the small primary sprocket needs to be changed, which can be replaced without dismantling the engine (rear wheel and clutch cover are removed for this).

64 TOOTHS
The 64-tooth version is aimed at small smallframes with 75-112cc or racing engines from 125-150cc that are used on small circuits at high speeds.
The BGM primary fills the gap of conventional primary drives between 3.00 and 3.72.
Cylinders with 85-105cc are often driven with a reduction ratio in the 3.20-3.05 range. More powerful engines 102-115cc) can also use the 2.91 without any problems.

65 TEETH
The version with 65 teeth is intended for engines with a displacement and high torque from 130cc. The long primary reduction of 2.50 is ideal for combining with a secondary shaft with a shortened 3rd and/or 4th gear. This means that the first two gears are longer and can therefore be used correctly, but gears three and four still connect perfectly due to the shortening on the secondary gear side. Furthermore, the spur gearing ensures maximum stability, but the gears still run very quietly thanks to the precise manufacturing. The otherwise typical 'whistling' of a straight-toothed drive is eliminated.

PROBLEM PRIMARY DRIVE
Smallframe engines use a steel clutch basket and thin cover plates for the shock absorber springs as standard. The relatively soft original Piaggio basket is deep-drawn and therefore not particularly precise in terms of concentricity and balancing. The thin cover plates are also prone to being worn through by the springs over long distances. If a spring, or a piece of it, ends up in the gearbox, this means a lot of damage.

SOLUTION
The BGM PRO primary set offers the great advantage that a clutch basket from any manufacturer can be used. Many small tuning companies (e.g. Fabbri or Benelli) offer perfectly fitting parts with a reinforced CNC-machined basket, reinforced springs and thick cover plates.

To complete the primary drive, the following is required:

• Clutch basket (e.g. Fabbri Racing). Fabbri Racing, Egig)

• Primary repair kit (if not included in the clutch basket)

• We have both parts in stock in different versions and quality grades (see accessories)

Conclusion: Ideal for all those who want to have a free choice in the construction of their primary in high quality.