GP7145GB-2.4 and GP7255AGB-2.4 Repair Instructions

TO CHECK VALVES

Loosen plugs (58), take out tension spring (57) and then remove the complete valve assembly (51) with either a valve tool or an M16 hexagon screw. To remove the valve adapter (56) and tension spring (57), use a pullout tool size 5. To disassemble valve assembly, carefully hit the top of the valve plate (51C) with a metal dowel and press the valve seat (51E) out of the valve adapter (56). Check sealing surfaces and replace worn parts. Check O-rings and support rings. Tighten plugs (58) to 107 ft.-lbs. (145 NM).

TO CHECK SEALS AND PLUNGER PIPE

Loosen nuts (49A) and remove pump head (50). Separate the plunger connection (36A) from the cross- head (25) by means of two open-end wrenches (size 22mm and 27mm). Pull seal sleeves (39) out of their fittings in the crankcase (1). Take the seal case (38) out of the seal sleeve (39). Examine the plunger parts (36A-36D), seals (42 & 39A) and O-rings (38A & 38B). When replacing the plunger pipe (36B), tighten tension screws (36C) to 30 ft. lbs. (40 NM). Replace worn parts; grease seals with Sili- cone before installing.

CAUTION: Don't loosen the 3 plunger connections (36A) before the valve casing has been removed otherwise the tension screw (36C) could hit against the valve adapter (56) when the pump is being turned. Seal life can be increased if the pre-tensioning allows for a little leakage. This assists lubrication and keeps the seals cool. It is therefore not necessary to replace seals before the leakage becomes too heavy and causes output and operating pressure to drop.

MOUNTING VALVE CASING

Check O-rings (38A & 38B) on the seal case (38). Clean surfaces of seal sleeves in gear box and sealing surfaces of valve casing (50). Push the valve casing carefully on the O-rings of the seal case and center- ing studs (50A). Tighten nuts (49A) to 103 ft. lbs. (140 NM).

TO DISASSEMBLE GEAR

Take out plunger (36) and seal sleeves (39) as described above. Drain the oil. After removing the circlip ring (33B), lever out seal retainer (33) with a screw driver. Check seals (32 & 33A) and surfaces of crosshead (25) .

Important! Seal (32) must always be installed so that the seal-lip on the inside diameter faces the oil. Possible axial float of the seal retainer (33) should be compensated with the shims (33C).

Remove the crankcase cover (4). Loosen inner hexagon screws on the connecting rods (24).

Note: Connecting rods are marked for identification. Do not twist connecting rod halves. Each con- necting rod is to be reinstalled in the same position (and orientation) on the crankshaft journals.

Push the connecting rod halves as far into the crosshead guide as possible. Take out the bearing cover (14).

8

Page 7 Page 9
Page 8
Image 8
Giant operation manual GP7145GB-2.4 and GP7255AGB-2.4 Repair Instructions, To Check Valves
Page 7 Page 9

GP7255AGB, GP7145GB specifications

The Giant GP7255AGB and GP7145GB are two notable models in the Giant range of bicycles, specifically designed for performance and versatility in varied riding conditions. These models reflect the brand's commitment to quality engineering and innovative technology, appealing to both casual riders and serious cyclists.

The GP7255AGB is characterized by its robust yet lightweight aluminum frame, which offers a perfect balance between durability and agility. This model features an advanced suspension system designed to absorb shocks and provide a smooth riding experience on uneven terrains. One of the standout features is its adjustable rear shock, allowing riders to customize the compression settings based on their preferences and the riding environment. With a wide range of gears, the GP7255AGB makes climbing steep hills effortless while ensuring quick gear transitions on flat stretches.

In addition to its performance-oriented design, the GP7255AGB is equipped with high-traction tires that enhance grip on various surfaces, ensuring stability and control during rides. The bike also incorporates reflective elements for improved visibility, making it a great choice for nighttime or low-light commutes.

On the other hand, the GP7145GB model signifies a fusion of style and functionality. With a sleek frame design and integrated components, this model prioritizes aerodynamics without sacrificing comfort. It features a lightweight carbon fork that reduces weight and increases response time during rides, making it ideal for road cycling enthusiasts.

The GP7145GB boasts a performance-enhanced gearing system, allowing for a wide gear range that caters to both intense climbs and fast descents. The bike is equipped with premium disc brakes for consistent stopping power, regardless of weather conditions. The ergonomic handlebar design also plays a critical role in rider comfort, allowing for longer rides without fatigue.

Both models utilize advanced technologies such as internal cable routing and a precise gearing system that offer a clean look and ensure low maintenance. The inclusion of a modern digital display on selected models provides riders with vital statistics such as speed, distance, and battery life for e-bikes, enhancing the overall riding experience.

In summary, the Giant GP7255AGB and GP7145GB represent the pinnacle of bicycle engineering, combining innovative features, advanced technology, and user-centric design to cater to diverse cycling needs. Whether navigating rugged trails or smooth urban streets, these models stand out as excellent choices for cyclists seeking performance and reliability.
Top Page Image Contents