answers will vary on this one, top engine guys will tell you 10 race weekends. THey don't last like the steel ones that is for sure, especially the exst. side. 1 of the motors we freshend up recently had exst. valves that were quite pitted after a season. (say 10-12 race weekends but duties were divided between my 2 bikes). Another r6 i just got that had a LONG season on it still made good power, but had 5-9% leakdown. Nearly all was from the pitted exst. valves. I am replacing all the valves on this bike. I dont see any reason you can not get 1-2 years of track days or occasional club races, or more, without trouble. Even The above, especially the bike i just got, were used pretty hard with race fuel. I know guys with 20,000 or MORE miles on street bikes (06-07) with no problems.
you are going to $hit when you see the price of those valves.....and I thought the Suzuki ones were $$$$.
for the price of a complete new set of valves, you can find a used motor. Any 06-09 head will work. If you can locate one with few miles, may be a good way to go, then ebay the head and low end? Call Kevin Ridgeway at Cahill's Yamaha in tampa.. http://www.cahillsyamaha.com/ he's the parts mgr there and may offer racers a discount. I get ALL my Yamaha parts there. Springs are pretty cheap (thank goodness). I put Kibblewhite steel valves in my crf450 after mushrooming numerous Ti honda intake valves. Many months of 2x week riding and have not even had to adjust them (but it is getting harder to start lately-1st sign of an adjustment in my future)
yeah I have been looking. does an 08-09 motor bolt up to a 06-07 frame? I will try Kevin after I figure out what I want to do.
