2011 Yamaha XT660X 0.7L Petrol · YT11 HPC

The 2011 Yamaha XT660X presents a mixed MOT history with a single documented failure in early 2017 followed by seven consecutive passing tests up to May 2024. The 2017 failure involved a severely loose rear drive chain (coded 6.2.1d), compromised rear tyres including a cut exceeding dimensional limits and insufficient tread depth below the 1.0mm legal threshold, plus a front tyre worn close to the legal minimum. Since then the vehicle has cleared every MOT test with no reported defects, indicating it remains roadworthy under current conditions though the 2017 issues should still be understood in context of the car's overall reliability trajectory. With 25,858 recorded miles accumulated over approximately 15 years, the average annual distance of roughly 1,724 miles places this machine well below typical usage patterns for its model year, suggesting either very light operational demand or extended periods of inactivity such as seasonal storage. The gap between the 2017 failure and the first clean pass in 2018 provides a nine-month interval before the next failure, while the subsequent six-year span from 2018 through 2024 shows consistent compliance across multiple test cycles. While low mileage does not inherently signal neglect, it does mean the suspension bushings, brake components and drivetrain have not been subjected to heavy cyclic loading, which may delay the manifestation of some wear patterns despite the absence of active failures. The rear drive chain failure from 2017 represents the primary mechanical concern requiring verification at purchase—the chain being excessively loose would typically produce audible clunking or skipping over bumps and could compromise power transfer under load. The rear tyres present two distinct problems: one tyre bears a cut deep enough to reach the ply or cords, which compromises lateral grip and handling, while the other tyre's tread has fallen below the mandatory 1.0mm minimum, creating a safety hazard on wet or contaminated surfaces. Additionally, the front tyre measured wear approaching the legal limit indicates potential scuffing that may affect braking performance and should be inspected visually and measured against the manufacturer's minimum specification. During the test drive, listen carefully for any clicking or rattling from the rear axle when accelerating or decelerating, as a loose chain often manifests as a metallic knocking sound rather than smooth engagement. Inspect both rear tyres by running your finger along the tread grooves—any visible cut or abrasion extending toward the reinforcement plies requires immediate attention—and measure the remaining tread depth with a ruler to confirm whether it meets the 1.0mm requirement. For the front tyre, check the contact patch width and look for uneven wear bands, noting any area where material has worn down significantly compared to the opposite side. If any of these observations match the recorded failures, the vehicle should not be considered safe for regular road use until the identified components are repaired according to OEM specifications.