A defining engineering highlight of the 1976 Suzuki GT 250 (GT250A) is its ‘Ram Air’ cooling shroud. While the 250cc model did not feature the massive cast-on shroud of its larger GT380 and GT550 siblings, the ‘A’ model benefited from Suzuki’s refined porting and the final evolution of their two-stroke parallel-twin design before the industry shifted toward the GS-series four-strokes. The GT250A was specifically lauded for its disc brake performance and improved reliability over its predecessors.
| Specification | Data |
|---|---|
| Model Year | 1976 |
| Engine Type | Two-Stroke Parallel Twin |
| Transmission Oil | SAE 20W-40 (0.8 L) |
| Front Tire | 3.00 – 18 4PR |
| Rear Tire | 3.25 – 18 4PR |
| Front Pressure | 1.8 bar (26 psi) |
| Rear Pressure | 2.0 bar (28 psi) |
| Battery | 12N5-4B (12V) |
| Spark Plug | NGK B8HS |
Engineering Overview
The GT250A represents the pinnacle of mid-70s lightweight motorcycling. By 1976, Suzuki had perfected the CCI (Crankcase Cylinder Injection) system, ensuring that the engine received precise lubrication without the need for pre-mixing fuel and oil. The GT250A was capable of producing approximately 26-30 horsepower, making it a formidable competitor in the quarter-liter class against the Yamaha RD series.
Maintenance & Service Guidelines
Lubrication System
For the gearbox, MotoSpecsLab recommends using a high-quality SAE 20W-40 oil. The capacity is strictly 0.8 Liters. Overfilling can lead to aeration and shifting issues, while underfilling risks premature wear on the primary drive gears. Ensure the CCI pump is bled correctly if the oil lines have been removed.
Tires and Handling
The GT250A utilizes 18-inch wheels front and rear. For optimal cornering stability and carcass longevity, maintain 1.8 bar (26 psi) in the 3.00-18 front tire and 2.0 bar (28 psi) in the 3.25-18 rear tire. Given the age of these machines, modern rubber compounds in these vintage sizes will significantly improve the ‘flickability’ of the chassis.
Electrical & Ignition
The 12N5-4B battery powers a relatively simple electrical system. However, the ignition timing is critical on these two-strokes. Use NGK B8HS spark plugs; these are heat-range optimized for the GT250A’s combustion chamber temperatures. Check for a healthy 0.6-0.7mm gap to ensure consistent firing under load.
MotoSpecsLab Editorial Verdict
The Suzuki GT250A is a masterclass in mechanical simplicity and tactile feedback. As a classic, it offers a visceral two-stroke experience with better manners than the earlier ‘Hustler’ variants. For the collector or enthusiast, maintaining the 1976 model is straightforward, provided the technician respects the specific lubrication requirements and period-correct tire pressures outlined above.