Mines just failed the second time 5500 miles and about 250 hours
First time, was in the middle of a race and only discovered it at the end, and there was only about 200ml of oil left in it (Mid 2010 - approx 50 hours)
Replaced it with Gen Yam seal and spacer even though there was no visible wear on the spacer
Just discovered its started to leak again today
No oil loss this time, as looks like its just started to leak, as its oily around the sprocket which isn't chain lube
At £20 for a pop for the seal I expect better from Yam
Looks also like I will be replacing it every year now, as an oil seal failure results in the engine oil leaking out (as the oil is under pressure behind this seal) and that'll end in tears!
Last time it failed, I also bought some off the shelf oil seals of the correct size as I had intended to use them if it ever failed again, but when the Gen Yam seal arrived, I noticed its not a normal oil seal - its got direction arrows moulded into to show direction of rotation, and ribs moulded onto the lip at 45 deg, plus the lip is longer.
With so much at stake if it fails, I never tried the off the shelf seals
Anybody else had any failures, or using just a bog std off the shelf oil seal with success
Edited by GuyGraham, April 28, 2013 - 09:24 AM.