My bike came with a 520 conversion kit and the downgearing in the sprockets, maybe 15/43. Anyway there was a lot of noise coming from the front sprocket area so I got a stock 525 chain geared to 16/42. I got the Motion Pro breaker and rivet kit, which by the way is total junk and maybe will get you one chain put on. It looks like the key pieces are potmetal and broke the anvil and a couple of the pin pushers. Upon further examination of the existing 520 Kit, the riveted master link almost looked like it was pushed on and not even riveted, no visible mushrooming on the rivets. The pins on the master link were all rusted out and no lube on the inside. The existing chain and sprockets were in good condition with no stretch on the chain or side to side movement. The front sprocket was all rusted up on the splines to the driveshaft so I wirebrushed the splines and greased them up. The DID chain and sprockets went on well and we will see if my driveline noise is better. Also looking forward to having my speedo not off by 8 mph. Thats my experience from yesterday and I will give an update on the set after riding today.