I only race my banshee i rebuild it from the ground up every winter and reabuild the topend every 10 to12 hrs oil changed after each race , only run 113 gas, right now i got 10 hrs on my topend and have ice racing right now ill rebuild it after thats done , my yfz is a back up / mx racer its got a 1000$ ported head on it and i rebuild the topend every 20hrs oil changed after each race if u keep your stuff up its going to last a long time