fits make: Yamaha.

( Part Type: Piston )
The GP643 Pistons 2nd Yamaha O.S. are high-quality replacement components designed specifically for Yamaha outboard engines. These pistons are meticulously engineered to provide superior performance, reliability, and durability.
The GP643 pistons feature a forged construction, which ensures strength and resistance to wear and tear. The piston skirts are designed with a optimal crown shape, promoting optimal compression and efficiency. The piston rings are made from a high-temperature material, ensuring excellent sealing and preventing oil leakage.
The pistons are precision-machined to ensure a perfect fit with the engine's cylinder, ensuring smooth operation and minimizing the risk of engine damage. The piston heads are designed with optimal combustion chamber shape, promoting optimal fuel-air mixture and efficient combustion.
The GP643 Pistons 2nd Yamaha O.S. are also designed with a balanced weight distribution, reducing engine vibrations and promoting a smooth and quiet operation. The pistons are also coated with a special anti-corrosion coating, ensuring longevity and protection against corrosion and marine environment.
In summary, the GP643 Pistons 2nd Yamaha O.S. are high-quality replacement components that are designed to provide superior performance, reliability, and durability. They are meticulously engineered to ensure a perfect fit with the engine's cylinder, promote optimal combustion and efficiency, and reduce engine vibrations and promote a smooth and quiet operation. The pistons are also coated with a special anti-corrosion coating, ensuring longevity and protection against corrosion and marine environment.
Pros of buying GP643 pistons 2nd Yamaha O.S:1. Compatibility: GP643 pistons are specifically designed for Yamaha outboard engines, ensuring a perfect fit and optimal performance.
2. Quality: These pistons are manufactured by a reputable company, ensuring high-quality materials and craftsmanship.
3. Cost-effective: Replacing pistons can be an expensive repair, but buying second-hand pistons can save you money without compromising performance.
4. Easy to install: Replacing pistons is a relatively straightforward task, making it a DIY-friendly project for many boat owners.
Cons of buying GP643 pistons 2nd Yamaha O.S:1. Wear and tear: Second-hand pistons may have some wear and tear, which could potentially reduce their lifespan or affect their performance.
2. Unknown history: You cannot be sure about the previous usage and maintenance of the pistons, which could lead to hidden issues.
3. Risk of mismatch: While GP643 pistons are generally compatible with Yamaha outboard engines, there might be specific model-specific variations that could cause issues.
Conclusion: Buying second-hand GP643 pistons for your Yamaha outboard engine can be a cost-effective solution, but it comes with some risks. It is essential to thoroughly inspect the pistons before purchasing to ensure they are in good condition. If possible, purchase from a trusted seller with a good reputation, and consider having a professional inspect the pistons before installation to avoid any potential issues.
Recommendation: If you are comfortable with the risks associated with buying second-hand pistons and have the necessary knowledge or resources to inspect them thoroughly, it can be a good option to save money. However, if you prefer peace of mind and want to ensure the best performance, it might be worth investing in new pistons from a trusted source.
Unfortunately I do not have the original box's. Offer is for a pair of nos new old stock second over size Yamaha pistons part.
I purchased the pair for a thunder jet project and found out later the engine was unable to be used, the piston's can also be used in 1972 ew643 GP643, 1973 ew643b GP643b.