Cylinder -DR 177 cc 3 Ports- Vespa P125-150, GTR125 (VNL2T), TS125 (VNL3T), Sprint150 Veloce (VLB1T 0150001-)

The DR177 has been on the market for a very long time and has rightly earned its reputation for reliability as a touring favourite for the 125/150cc models.

Its simple basic design predestines it for a simple but effective tuning, just by replacing the stock cylinder with the DR177. The engine then allows driving performance that roughly corresponds to that of a PX200. Its compression ratio is very moderate, the overflow cut-outs at the cylinder base correspond to those of the standard cylinder. Thus, it offers ideal prerequisites for tuning beginners.

Technical characteristics:
Bore = 63 mm
Displacement = 177 cc
Compression ratio = 1:8,5
Stroke = 57 mm
Piston = Ø 63
Power = 9-12hp at rear wheel
Ignition timing: 19-21°

In contrast to the Polini 177 it offers a slightly more broadband, not quite as high-torque characteristic. In everyday life this is very nice to ride and also harmonizes very well with the stock components like carburetor, exhaust and crankshaft. Due to its three-part exhaust port (two additional small secondary exhaust ports) it can reach speeds of up to 110 km/h even on the rather short 125cc original gearbox.

The so-called “box” exhaust systems such as the BGM Touring or the Polini original box have turned out to be a good combination here. Both still provide the required tractive power with an extended gear (e.g. special 23 tooth sprocket or BGM Superstrong clutch) and are also visually and acoustically very inconspicuous.

CYLINDER TUNING

PISTONS/RINGS
The piston uses two 2mm thick cast piston rings. These can be replaced by steel piston rings from Grand Sport (Art.No.: 7673026) if you want to run the cylinder on a short reduction and/or further overhaul (PX125/150 original) and thus demand correspondingly high revs. These are also useful if the exhaust port is to be widened. The whole piston can also be replaced by a Grand Sport or BGM piston. In this case, however, the running clearance should be checked individually and adjusted if necessary (~1/10mm).

OVERFLOW PORTS
The cylinder base has concealed large overflow cross sections. By simply milling away the thin sealing surface overlap, the cross-section can be brought to Polini177 dimensions (simply put on its foot gasket and mark it).

SEALING
The DR177 has a very tame compression ratio ex works (specification DR = 1:8,5). The cylinder head can be planned by approx. 0.8-1.0mm. This gives a geometric compression ratio of approx. 10.5:1. Alternatively, the cylinder head of the Polini 177 can be used. This compression increase offers a big jump in power and torque, but should always be accompanied by a re-check of the carburettor jetting and ignition setting.

STEERING ANGLE
Out of the box the DR has steering angles ( approx.117°/164° OB/AS) that are quite similar to the original PX200. To increase power over the entire rpm range, raising the cylinder 0.5mm at the base and machining the exhaust (height + 0.6-0.9mm) has proven ideal.

This allows the cylinder to reach head angles of 120°/170°, which means it responds much better to further measures such as reworking the intake (crankshaft with longer intake angle, SI24 carburettor) as well as the measures listed above.

The DR is thus able to achieve approx. 14-15 HP which, provided everything is properly tuned, can also be called up permanently without any problems. We do not recommend the use of a resonance exhaust on the DR, although this is also possible with the appropriate further revision (control angle).

ALTERNATIVE
The BGM177 is a high quality alternative to the DR177. The power and torque are, with identical speed range, significantly higher with the BGM177. As a hard-coated aluminum cylinder, the BGM177 is even more durable and fuel-efficient than the DR177. The BGM177 is also plug and play compatible, so it works with all stock components of the existing engine. However, it still offers great tuning potential upwards if required.

TIP: Can also be used on motors with only two overcurrent channels. Please check if the upper overcurrent channel (also called boostport) of the cylinder is sufficiently covered by the housing.

FITS :

• LML 125 (2 stroke)
• LML 125 Deluxe (2 stroke)
• LML 125 DLX (2 stroke)
• LML 125 Stella (2 stroke)
• LML 125 Via Toscana
• LML 150 Belladonna (2 stroke)
• LML 150 Belladonna RV (2 stroke)
• LML 150 DLX (2 stroke)
• LML 150 Star (2 stroke)
• LML 150 Via Toscana (2 stroke)
• Vespa (Motovespa) Vespa 125 CL (engine 9CL)
• Vespa (Motovespa) Vespa 150 CL (engine 9NC)
• Vespa (Motovespa) PX 125 Iris (engine 99M)
• Vespa (Motovespa) PX 150 Iris (engine 75M)
• Vespa (Piaggio) 125 PX E FL (2017-, ZAPM74100)
• Vespa (Piaggio) 150 PX E FL (2017-, ZAPM74200)
• Vespa (Piaggio) 125 PX E FL (2016-, ZAPM74100) special edition “70 years”
• Vespa (Piaggio) 150 PX E FL (2016-, ZAPM74200) special edition “70 years”
• Vespa (Piaggio) Vespa 150 Sprint Veloce (VLB1T)
• Vespa (Piaggio) Vespa 125 GTR (VNL2T)
• Vespa (Piaggio) Cosa 150 CL (VLR1T)
• Vespa (Piaggio) Cosa 150 CLX (VLR1T300)
• Vespa (Piaggio) Cosa 150 FL (VLR2T)
• Vespa (Piaggio) P 150 X (VLX1T, -1980)
• Vespa (Piaggio) PX 150 E FL (VLX1T, 1984-1997)
• Vespa (Piaggio) PX 150 E (VLX1T, 1981-1983)
• Vespa (Piaggio) Vespa 125 TS (VNL3T)
• Vespa (Piaggio) Cosa 125 CL (VNR1T)
• Vespa (Piaggio) Cosa 125 CLX (VNR1T300)
• Vespa (Piaggio) Cosa 125 CLX (VNR1T301)
• Vespa (Piaggio) P 125 X (VNX1T, -1983)
• Vespa (Piaggio) PX 125 E FL (ZAPM09300, 1998-2000)
• Vespa (Piaggio) PX 125 E FL (ZAPM09302, 2001-)
• Vespa (Piaggio) PX 150 E FL (ZAPM09400, 1998-2000)
• Vespa (Piaggio) PX 150 E FL (ZAPM09401, 2001-)