YZ vs. WR durability

Good Morning,

Do you guys think a WR will go twice the distance than a YZ before teardown or valve replacement? ......being all things equal riding both in the woods and not racing? I know the WR is bulletproof and will last a little longer with it's lower comp. and mild cam but I aint screaming 'em all day anyhow so either is gonna last a while for me. Just wodering if it's THAT's much of a durability difference of the WR going say 3-4 years vs YZ's 2 years or so before rebuild.

Semper Fi, .......I'll post this in the WR section as well.

~Lee

No. For one thing, it has the same compression, and compression imposes no penalty in terms of longevity. For another, they use the same valves in a nearly identical head. Both ridden under the same conditions, one will last as long as the other. The WR is obviously subject to more frequent electrical problems because it has a vastly more complicated electrical system.

You should base the longevity on other things than just years. Hours are a good place to start. Other things like type of oil and the frequency of oil changes will play a part. Air cleaner maintenance and the type of air filter oil is also very important. And lastly, I would look at the type of riding and how much time is spent at higher rpm's.

If you are trying to decide which bike to buy I will give my two cents worth. I have owned an 07 wr450 and now an 09 yz450. The yz is so much better and feels 50lbs lighter while riding compared to the wr that even if the yz had to be rebuilt sooner, I will never own another wr. There's that much of a difference.

I ride everything from nasty tight single track to hauling ass desert riding and the yz is magical!

base it on the yfz450 quad engine comments:nearly bulletproof even though the ONLY electrical problem is lights have to be on when electric starting on 2007 models ONLY

So Gunner, ever ride a 230 or 300 smoker if the light weight thing appeals so much or is the yz just right?

I ride everything from nasty tight single track to hauling ass desert riding and the yz is magical!

In either of these conditions the WR will be much better than a YZ IMO. I had a YZ450 and sold it for a WR and never looked back. I was always boiling over the YZ in the really tight technical trails and it just didnt have the top speed for more open riding. Everything in between these though the YZ will shine. I also was not a fan of the YZ suspension for the woods.

and it just didnt have the top speed for more open riding.
If you found that you needed more than the 80+ mph top end of the YZ450, my hat's off top you. My only complaint is that I don't like holding the engine at 9000+ for a 30 second run across a lake bed, but I think I'll correct that with a WR trans.

A WR is a good place to start, too. It just depends on where in the middle you eventually want to end up.

http://www.thumpertalk.com/forum/showthread.php?p=8107235#post8107235

Grayracer you can hold the bike at 9000 for 30 seconds safely with 2 fingers on the clutch just hold it in after each 30 seconds take it a 1/4 mile at a time its like 10 seconds then pull in the clutch you will be amazaed how these bikes can go on for more than 1 minute with 15tooth front sprocket at 95 mph stock gear

I think after over 45 years of riding and racing, and over 35 years as a professional mechanic and builder, I have all that pretty well worked out. You do it your way.

The load on the reciprocating assembly of an engine is in many ways higher at part throttle than full throttle when running at high RPM because there is so little compressive force over the piston to counter the tensile loading of going over TDC. With the just higher than stock gearing I run, there's very little load on the engine running 9000+ and holding a steady speed. It is capable of it, but it isn't good for it, and I still don't like it.

i respect your opinion based on your profession as a mechanic maybe a bigger front sprocket can get you there at 8000 rpm if you want to try

Yes, I could run a 15/49 instead of the 13/48 I currently run, and get the same speed at 8000 as I now get at 9000. Then I would have a first gear that was 15% higher than it already is. No thank you.

The WR trans, on the other hand, delivers that same speed in fifth while providing a lower first gear at the same time.

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