GY6 engine

The GY6 engine was originally developed by Honda for use in its motor scooters.[1] It was later adopted by many light vehicle manufacturers across China and South East Asia. The 150cc examples are popular alternatives to 50cc Honda Ruckus owners as candidates for engine swaps.

Configuration

The GY6 design is a single-cylinder, four-stroke engine, in a near horizontal orientation. It is forced-air cooled, with a chain-driven overhead camshaft and a crossflow hemi head. Fuel metering is by a single constant-velocity style sidedraft carburetor,[2] typically a Keihin CVK clone or similar.

Ignition is by CDI, with a magnetic trigger on the flywheel. Because the trigger is on the flywheel instead of the cam, the ignition will fire on both the compression and exhaust strokes, known as "wasted spark" ignition". An integrated magneto provides 50 V AC power for the CDI system and 20-30 V AC rectified and regulated to 12 V DC for chassis accessories (such as lighting), and to charge a battery.[2]

It includes an integrated swingarm, which houses a centrifugally controlled Continuously variable transmission (CVT) using a rubber belt sometimes called a VDP. At the rear of the swingarm, a centrifugal clutch connects the transmission to a simple integral gear-reduction unit. There is no clutch of any kind between the CVT and the crankshaft; it is engaged via a centrifugal clutch at the rear pulley in the same fashion as Vespa Grande, Bravo and variated Ciao model, as well as Honda Camino/Hobbit mopeds. An electric starter, backup kick-starter, and rear brake hardware is also housed in the swingarm.[2] There are variants known as the "short case" (10" rear wheel, 729, 735 or 742mm belt) and "long case" (12" or 13" wheel, 835 or 842mm belt). Final gearing ratio can be as low as 13/40, or as high as 18/36 (more commonly available as aftermarket from places such as ScrappyDogScooters or on eBay).

Variants

Specifications of GY6 variants[3][4]

Engine Displacement Power Bore × stroke Compression ratio
139QMB 49.5 cc (3.02 cu in) 2.95 hp (2.20 kW) at 7,500 rpm 39 mm × 41.4 mm (1.54 in × 1.63 in) 10.5:1
152QMI 124.65 cc (7.607 cu in) 6.8 hp (5.1 kW) at 7,000 rpm 52.4 mm × 57.8 mm (2.06 in × 2.28 in) 9.2:1
157QMJ 149.6 cc (9.13 cu in) 8.6 hp (6.4 kW) at 7,000 rpm 57.4 mm × 57.8 mm (2.26 in × 2.28 in) 8.8:1

The GY6 engine is made by many different manufacturers in Asia, so there are many small differences between the engines. Commonly, the piston/cylinder bore measures 57mm for scooters, and 57.4mm for karts, quads, and buggies (and often features a reverse gear in the engine case). The better quality builds tend to come from Lance and SYM (both Taiwanese companies). Jonway is probably the most dependable marque in regards to China-made goods.

References

  1. ↑ "HONDA GY6 ENGINE 50cc to 150cc". GOKARTS USA. Retrieved 16 February 2015.
  2. 1 2 3 "About GY6 Engines & Components". Retrieved 17 February 2015.
  3. ↑ "La verdadera historia del Motor GY6". 27 October 2011. Retrieved 17 February 2015.
  4. ↑ "MOTORCYCLE ENGINE-Products World— 1P39QMB 1P39QMB". Retrieved 11 September 2015.

Further reading

This article is issued from Wikipedia - version of the 12/4/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.