OK so I spoke to B&C Express and they said that just by looking at the hooking on the teeth they have determined that the chain is too loose. I argued the point with them that actually it is within the manufacturers specifications and they eventually agreed that if I send it back to them they will have a look at it and if necessary send it back to renthal for inspection but that it is unlikely that they will come to any other conclusion. I am pretty disappointed at this response and have never heard of a loose chain causing this kind of wear. They did sell me a new steel JT sprocket with free postage so that I can replace the renthal one which is a small consolation. Hopefully I will have better luck with that one.

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Now have a 2017 S1000XR Sport SE

2006 XT660X - Cat D write off due to someone pulling out on me - Pipewerx carbon fibre exhausts - Snorkel removed and airbox drilled - DNA stage 1 + 2 air filters - Kevs fuel controller mod - Scottoiler V system - Oxford heated grips - HEL braided brake hoses - Wilbers 540 rear shock - Brembo brake pads - AFAM chain and sprockets - Michelin Pilot Street Radial's - Denali DX Xtreme dual intensity spotlights