milage to top end rebuilds

[panda38]

I have a 2007 wr450 with 7000km on it and am wondering what kind of mileage people are getting before having to redo the top end?

[Just_a_trail_rider]

Just last year I put a new piston and rings on my wr450. I changed the timing chain too. That would be 5 years and well over 8000 miles. No changes or adjustments to the valves. I was prepared to do the valves as well, but it did not need it.

Oh, it was running perfectly at the time. I did the top end because I was curious. Piston showed that it was burning a little oil. But I never noticed since I change the oil every other ride.

[tribalbc]

I have a 2007 wr450 with 7000km on it and am wondering what kind of mileage people are getting before having to redo the top end?

The big question is what kind of km's. Racing, hillclimbing, wide open riding, then you're getting close. Trail putting, you got a ways to go. Are you burning oil, valves moving, oil in the airbox? These are signs that it is time.

[panda38]

no racing, just about all tougher single track. not burning oil yet. did get the first valve adjustment this spring at 6000k. air box is dry so hopefully many more k's to go yet.

[Just_a_trail_rider]

no racing, just about all tougher single track. not burning oil yet. did get the first valve adjustment this spring at 6000k. air box is dry so hopefully many more k's to go yet.

That sounds like mine. I ride slower trails 95% of the time. I had some noticeable wear on the rings which caused a little oil to burn. But the engine ran great and I had little to no idea it was burning oil. Obviously, it wasn't burning enough for me to notice.

my airbox would always be a tad bit wet, but probably because I routed the crank breather hose to the bottom of the airbox.

The process of changing the piston was pretty simple. I won't let it go that long again.

[tribalbc]

my airbox would always be a tad bit wet, but probably because I routed the crank breather hose to the bottom of the airbox.

.

Crank breather hose blowing oil is a sign that the rings are gone unless you are overfilling oil.

[Just_a_trail_rider]

Crank breather hose blowing oil is a sign that the rings are gone unless you are overfilling oil.

Didn't realize that before. I was checking the exhaust and there was no oil there. It sure was hard to tell anything was wrong based on how the bike was running. I rarely use more than 50% of the available horsepower of the wr.

My airbox has been pretty dry since. At least when the bike is rightside up and not upside down and on top of me!

The lesson is... follow the maintenance plan setup by Yamaha and don't wait for something to go wrong.