I did not have to file any of my valve guides. Granted I did go with after market valves (1 mm over) but they met specs without any modification. I feel like changing timing chains every 100 hours is extremely excessive on a bike with an automatic cam chain tensioner. I see no need it changing it that often. If your tensioner is working properly and you are running a good oil, there is no need to change that chain until it begins to show wear. I wouldn't expect this to be more than once a year even on a very heavily ridden drag bike.

~HoundDog

 

the guy that built my motor grind down one of my valve. if i remember correctly it said to do this with the intructions that came with the hotcam.