You can adjust the bracketed details to fit the exact item you found. Unlocking the Mystery: What is the Yamaha 5BS 661? If you’ve stumbled across the code Yamaha 5BS 661 —on a carburetor, a bracket, a vintage engine case, or a parts list—you’re not alone. This isn’t a mainstream model name like “YZF-R1” or “Clavinova.” Instead, you’ve likely found a genuine OEM part prefix from Yamaha’s golden era of engineering.

Drop it in the comments, and we’ll help ID the exact model. Disclaimer: Yamaha part numbers change over time. Always verify fitment with a dealer or factory manual before purchasing or installing used parts.