Manual - Yamaha R15 V4 Service

But page 201 changed everything: a tiny footnote in red— “If engine knock persists after cam chain tensioner replacement, check the VVA oil pressure control valve. Clean with compressed air. Do not disassemble.”

He found the valve buried under the throttle body, caked with carbon and metal shavings from the wreck. A shot of brake cleaner, a soft brush, and ten minutes later—the bike roared to life. No knock. No smoke. Just a clean, angry idle. yamaha r15 v4 service manual

The Gospel of the R15