hey

have any of you mojave owners had the problem of getting motor oil in your airbox? what does this mean? Are my valves somehow pushing it back through the carb?

After i ride for a while and look at my airbox drain tube, it's full of motor oil, not air filter oil... Sometimes there's quite a bit of oil in there, like over 3oz. i dont understand this! Do my valves need to be adjusted? usually i can figure this stuff out, but i'm stumped fellas!

 

did you over fill you engine with oil when you changed the oil last time?

 

it's on the upper level line on the bubble, which is full, but not overfull... i have to add oil all the time to keep the oil in b/w the 2 lines on the bubble

 

Hey


Ok the oil in your airbox is really nothing to worry about. I get it all the time too. If you look just under your carb, there is a tube that has an elbo shape to it. It goes from your engine straight to your airbox, that's why there is a drain tube on the airbox. The oil drains back there anytime the front end of the quad comes up, like if your doing wheelies, or maybe climbing hills. When you drain the oil out of the tube you can just put it back in if you want, but thats why the tube is there because of extra oil. It's a weird design but it's nothing to worry about.

Hope that helped
Peace out!

 

THANK YOU!!!

 

That's exactly what happened to me when I owned a mojave. I put a supertrapp EAR pipe on, and that's when it started happening.

Since I assumed this would never happen, I didn't check the airbox. One day, as I was riding around, my quad started smoking really bad - smoke was just pouring out of the exhaust. I thought I had blown a head gasket or something, since it was thick white smoke.

As I checked over the quad, sure enough, the airbox was brimming with oil. Drained it, and it took care of the problem.

The pipe must've caused reduced pressure in the crankcase, allowing oil to get out of the breather hose, since it never did this before the aftermarket pipe.

I was going to modify the breather hose by lengthing it, increasing the vertical height. That way, maybe oil wouldn't "climb" out of it.

I traded it in for a 400ex before I could experiment. Buying the 400ex was a much better solution! [img]i/expressions/face-icon-small-smile.gif[/img]

ogre

 

I have to disagree with Hossman. The tube is not suposed to flow any oil, and by no means should you put that oil back into the motor. The tube is called a crank case breather, and it is designed to allow air to flow into and out of the crank case to compensate for the piston going up and down. As the piston comes down in the bore, there is les room in the crank case for air, so this tube prevents the case from being preasurized. It is important to keep this tube flowing freely.

The oil in the box comes from air in the case picking up and blowing a small amout out. This is somewhat normal, and happens more when a quad is ridden at higher RPM's. If this starts to happen on a regular basis, is may be caused by "blow by". That may mean that your piston/rings/cylinder are worn and will not seal properly.

The drain in the air box is actually for water. If the quad is submurged, or water gets in the box in any other way[such as washing it], you need a way to drain the box to prevent the motor from sucking it up.

 

Knutz -

I'm still curious on why this happened to me (even though I don't own the mojave anymore). I don't know if you have intimate knowledge regarding the mojave (I know the DS is your specialty), but it can't hurt to ask.

For me, this only happened after the aftermarket pipe was installed (along with proper jetting, of course). This machine was relatively new, and didn't show signs of blow by. It was definitely coming from the breather.

I have heard a few accounts of this previous to the posts, so it may be a common occurrence.

Maybe you, and others, can shed some light on this. Also, I'd like to hear the experiences with this from mojave owners. After pipe and air filter mods, did this happen to you?

ogre

 

Any time you increase power, your also increasing cylinder preasure. So when you added your pipe and set your jetting, you were increasing the preasure and causing more blow by than previously. All motors have some blow by, and some new motors can't handle any more cylinder presure than stock, so this will cause the oil easier than expected. If the amount of oil is minimal[1-2 tablespoons per long hard ride] then there is nothing to worry about. If the amount of oil is more than that, then it is not a problem in itself, but a sign of an internal problem that will slowly but surely get worse.

 

I understand.

I just find it odd that mojaves are known to do this, but other machines don't (very often).

I mean, my 400ex has some mods (exhaust, piston, cam), and at every step in the modification process, I never get oil in my airbox.

ogre