3 days in sand, now I need a full rebuild

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One of the only ways it can suck sand up the breather tube is if the tube is buried in sand when the engine is shut off and the last stroke it makes is an up stroke. Even then it is unlikely any sand could make it to the head. As long as the engine is running, about an equal amount of air goes in as comes out, and in such a rapid succession that no sand has time to make it more than an inch or so up the 2.5ft tube.
This is correct. In fact, while the engine is running, there is a net outflow of air in even the healthiest engines as combustion blow by and oil vapor is added to the crankcase.

Starting or attempting to start the engine is usually the best opportunity for something to be drawn up into the breather. Any open vent line T'd into the breather hose near the top, even a much smaller one, will break the vacuum in the main hose well enough to prevent it from raising water or sand that far in any case.

Apparently it's very easy to do. I just got off the phone with the dealer and he has taken it all apart and said it definitely came in through the breather hose and a lot of it. It is everywhere. Need new cylinder, piston, rings, crank, etc etc ... He verified that the carb and air filter set up looked very clean in deed. I took it in there because a friend wanted to buy it off me so I said I would have the valve clearance checked by a pro just so we both felt good about the deal. In sand dunes you crest over razor backs all the time where the entire base of the engine plows through the sand, very easy for the breather hose to be completely submerged. I asked about that when I bought the bike and they said it only blows not sucks. Well now it really sucks. No wonder evryone else I saw in the dunes was on a crf. A $5 jimmy rigged filter on the end after rerouting it higher or in the air box would have saved me $3000.:worthy:

Next time buy a $80 aftermarket skid plate and you won't run into that situation again. It keeps the sand away from the breather tube and makes a nice sled.

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That's pretty slick. I think I have the same filter on mine but I zip ty it in the frame recess right above the front sprocket.

I have 07 yz450 read about this problem on this fourm here. Took my bearther hose off and had alot of dirt in there. My bike only has about 3 to 4 hour on it. I rerouted the hose in the airbox and put a filter on it. My bike never been on it's side either. So dirt can get up there. I beleve the is a kit form Yamaha for this problem.

Ive heard applied makes some type of breather tube kit for the crf450s but not for the yamahas.As for yamaha making a kit that would be news to me.

I always considered riding in the dunes to be an I.Q. test...I rest my case.

:worthy:

I always considered riding in the dunes to be an I.Q. test...I rest my case.

:worthy:

Well I don't know about how smart or dumb it is, as we do not have sand dunes here in N Ga but it would seem that if anyone rides in either sand or wet conditions exclusively w/o rerouting the breather, you are just asking for trouble and a big mess inside the motor.....I imagine dune riding with reg knobbies has to be way too much effort and a lot of motor stress. :worthy:

So I got to look at my engine all torn apart last night. Could definitely find gritty sand throughout and especially in the head where the breather hose drops in. It scored the cylinder and top of piston, wore little round depressions in the cams where the valves hit them, one valve stem had about 2mm shaved off it, sprokets that run timing chain have seraded type wear patterns all over them and the chain guide is all worn down. The pictures with the orange air filter thing, where did you get that filter?

I always considered riding in the dunes to be an I.Q. test...
Dunes are one of my favorite places to ride.

Apart from the fact that your post could be considered personally insulting, trolling, and just plain unfriendly, given the results of my last several IQ tests, I see a distinct flaw in your association of the two. :worthy:

.....I imagine dune riding with reg knobbies has to be way too much effort and a lot of motor stress. :worthy:
Speed is the secret. :worthy:

Where we ride, the dunes only cover part of the area. If you use sand tires, you limit your riding too much.

Next time buy a $80 aftermarket skid plate and you won't run into that situation again. It keeps the sand away from the breather tube and makes a nice sled.

I have a devol enduro skid plate on my bike but the breather hose is routed from factory right along the side of the frame by your shifter with a little turn down in the hose at the end meaning it's not that protected. Bottom line is there is no disadvantage to rerouting your breather hose and it could save your engine so just do it. No matter how much you may feel it theoretically can't get in through there it did on my bike. I've been told the new WR's have theres into a nipple in the air boot (between air filter and carb). That eliminates the need for a second filter but I would be very cautious about rigging something up like this incase your seal ever weakens. I like the pictures of the one in the air box with the orange filter. My air boot and carb are crystal clean, it got in through the breather hose for sure.

Dunes are one of my favorite places to ride.

Apart from the fact that your post could be considered personally insulting, trolling, and just plain unfriendly, given the results of my last several IQ tests,

What's up with that? You weren't happy with the results of the first test you took?

Wow!...........and I thought I had a big head.

I imagine dune riding with reg knobbies has to be way too much effort and a lot of motor stress. :worthy:

No, not really.

Paddle tires put a big strain on the motor too. You HAVE to stay on the gas hard to keep that paddle scooping like it should.

Like grayracer said, its all about momentum. Once you get moving, a knobby does fine.

So I got to look at my engine all torn apart last night. Could definitely find gritty sand throughout and especially in the head where the breather hose drops in. It scored the cylinder and top of piston, wore little round depressions in the cams where the valves hit them, one valve stem had about 2mm shaved off it, sprokets that run timing chain have seraded type wear patterns all over them and the chain guide is all worn down. The pictures with the orange air filter thing, where did you get that filter?

Shucks, only a couple of bucks, and it fits right in the existing tube.:worthy:

I always considered riding in the dunes to be an I.Q. test...I rest my case.

:worthy:

***?, kind of a stupid comment.:worthy:

The pictures with the orange air filter thing, where did you get that filter?
That particular unit is the fresh air filter/oil separator for an automotive PCV system of the type used on Ford products in the 1970's and beyond. You can find those and other similar designs at pretty much any auto parts outlet.
What's up with that? You weren't happy with the results of the first test you took?
There were some who wouldn't accept the results without the verification of multiple tests. :worthy:
***?, kind of a stupid comment.:worthy:
Arrogant.

But, having seen Glamis on a big weekend, it's understandable how someone might reach such a conclusion. :worthy:

There were some who wouldn't accept the results without the verification of multiple tests.

That low, huh?..............................just kidding!

I took an I.Q. test once. Then they put me on a short bus after that and they told me I was going to Sea World.

I took an I.Q. test once. Then they put me on a short bus after that and they told me I was going to Sea World.

That's some funny stuff.

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