Water in crank case oil? 2008 YZ450

We were out this weekend for some good offroading, and the conditions were a very wet out with lots of standing water holes and creek crossing. When we got back from the day, I checked my oil, and it was contaminated with water. I was stuck in a couple of holes, and had trouble kicking it over, but no dumps in the water. I was wondering if anyone knows where water typically comes in. Saw a small amount of water in another time. A buddy had his YZ filled with water too.

Can you suck water through the breather hose that runs below the drain plug. I need to check, but I think this is the head breather hose. Thoughts?

The engine will run with the breather hose under water, even at an idle in most cases, without a problem because the vacuum created by the piston upstroke reverses to pressure from the downstroke too rapidly for the engine to draw anything in.

However, if you stall, it may take a shot of water as the engine comes to a halt, and it almost certainly will if you try to start the engine with the hose submerged. If you are going to insist on doing this, you'll want to read this:

http://www.thumpertalk.com/forum/showthread.php?t=706602

I have the same bike and had the same problem. I rerouted my breather hose to the top of the airbox.

05-23-09_1902.jpg

So why exactly do they route it there in the first place? I know these are supposed to be track bikes, but this seems a little silly... Thanks for the posts.

Will this work?

No, it won't. I've said this before. Automotive PCV valves do act as one way check valves, but the problem is they don't flow an adequate amount of air in the other direction to serve as a breather for a thumper. They are metered one way, and shut off if flow exceeds a certain limit in the other.

So, once again, no, they won't work.

Cons:

  • The price is ridiculous
  • It's unnecessary

If you run the breather hose the way Jones did in the post I linked to, using a simple T near the high point, nothing else is necessary. I said that before, too, but for some reason, nobody wants to believe it.

Cons:

  • The price is ridiculous
  • It's unnecessary

If you run the breather hose the way Jones did in the post I linked to, using a simple T near the high point, nothing else is necessary. I said that before, too, but for some reason, nobody wants to believe it.

Using a "Tee" is best and can be done for almost nothing. I personally think guys just like having Grayracer repeating himself over and over and over......:crazy:

Thanks, I'll get on that...It should save me a bunch of work.

So why exactly do they route it there in the first place? I know these are supposed to be track bikes, but this seems a little silly... Thanks for the posts.

Even on the WRs this is the case......so it is silly,,,,,,no it is stupid:banghead:

Even on the WRs this is the case......so it is silly,,,,,,no it is stupid:banghead:
The WR has multiple vents, at least one of which routes to the air box, so a WR should not be subject to drawing anything of substance through the lower breather tube.
The WR has multiple vents, at least one of which routes to the air box, so a WR should not be subject to drawing anything of substance through the lower breather tube.

must be after 2003 - mine suxd up the Chattahoochee River and a whole lot of red clay....sold soon after. :crazy:

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