I have the 520 AFAM -1/+2 conversion with the DID 520 ERV3 racing chain. I've been having problems with my chain slacking way too much. I barely have 10000km on my chain and sprockets and now I notice there are piece of the x-rings coming out of the chain links and some links have already lost their rubber. Is this normal. I've been treating my chain to WD-40 and frances equipment white chain grease every 700km as indicated in the instruction manual. Is this normal wear and tear or do I have something wrong here.