'09 YZ450F-100 Hours-Time for Some Maintenance?

Got back into MX about 2 years ago after 20+ years off the dirt. Bought a new '09 YZ450F.

Just turned 100 hours. I've checked the valves twice and they've been fine. Bike still runs super strong, starts first kick. I'm old and slow (and 240lbs)...so I rarely see the rev-limiter. Oil + Filter has been changed every 3-5 hours, and I've never had any shaving on my magnetic drain plug. The bike has been a dream to own. Absolutely trouble free. I did buy some new clutch plates this week, so I am going to swap those out this weekend, even though the clutch isn't real bad.

So...should I just go ahead and do a top end, timing chain and ????

I want to keep this bike another 100 hours (since I have thousands invested in suspension/aftermarket goodies)...how do I get there?

I'd do the top end & cam chain. I just did mine at 110 hours and had some ring float and was starting to wear through the nikasil. Although I race, ride MX only it sounds like I might be a little harder on my yz. I think 100 hours for a top end is a good rule of thumb, it's $140 well spent !!

I replace my cam chain every 50 hours or so, replaced the first one at 60 hours and I had 7 links that were binding. If you're already doing the top end, for another $20 you may as well put a new one in there.

Same deal over here, in 110 hours my valves haven't moved !!


I did the top at 96 hours, call it 100 right! Did piston, rings, timing chain, valve springs and valve seals. Springs and seals are cheap. Still runs like new!!

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