I have a 1991 yamaha fzr 600r. the filter box keeps filling up with oil,,,,,,, the tube that goes from the breather box to the top of the motor is where the oil is coming from. i took off the breather, goosed it really hard, and then oil came spraying out of that hose????????????? can somebody pls explain this to me please/. asap?

SOURCE: oil blowing out of trans breather tube

hi 81 yamaha i am concerned about the fuel smell coming out with the oil. could be the carbs flooding filling your crankcase with fuel? if not it sounds like you have blow by which would cause your crank case to be slightly pressured. this is caused by worn piston rings. do not plug your crank vent. if you leave your vent open install small filter to stop dirt from entering jim

SOURCE: Gas & oil in air filter box

P.C.V (positive crankcase ventalation) valve is bad.

SOURCE: my 1991 yamaha fzr 600 wont start

how long did you let it sit for with gas in the carbs, you may have clogged up your jets. after awile gas will break down and turn into varnish, if your bike trys to push the varnish through the system it will clog the jets. try to take off your seat then remove your plastic over the gas tank. remove the gas tank and you will see four bowls *silver ones right next to where the gas tank is on the carbs*. your bowls are in sets of two. there are drain screws on the bowls to remove the gas inside. remove the 16 screws holding the bowl onto the carb. *4 on each* inside you will see your floats and jets. carefully loosen the jets with a screw driver then finish unscrewing them by hand, they are brass and very soft. you should be able to hold up the jets to the light and see a small pin hole. if not get some carb cleaner and give them a squirt and blow them out. do not try to use anything to clean them out, they are very very sensitive and one knick will change the jet. after that i would spray some carb cleaner up the jet holes and try to clean them out also. if you have a compressor it would be wise to use that to blow out the gunk from the jet holes as well. after you run threw all 8 jets put them back together and see how it goes, if nothing you may have to check the jets again and if clogged again your carbs are gunked up and will need to be cleaned

rtpflh

• 546 Answers
• Posted on Sep 29, 2009

SOURCE: oil leak out of a breather hose

a small amount of oil from the crankcase vent hose under hard acceleration is most likely normal.American bikes don't leak oil,they mark their spot!

SOURCE: oil blowing out through air-filter,rough

Your '98 Evo motor is what they call a "head breater" engine. This means that the crankcase ventilation is at the upper end of the heads rather than way down at the lower end of the engine like it used to be. They the first year for the "head breaters" was 1994.

Now, At the top of the heads where the rocker boxes are, there are three pieces. The lower rocker plate with the rocker arms in it, the middle piece and the upper cover. If you take the four bolts out, you'll see an umbrella valve in the middle piece of the rocker boxes. This valve is a replacable rubber piece. Over time and many times of heating up and cooling down, they can get brittle and allow a lot of blowby resulting in oil in your air filter element.

Now there is another part in the cam chest that has a lot of effect on the operation of the crankcase breather system on your bike. This part is called the "breather gear" and is located down in the cam chest to the rear of the camshaft. In you bike, the part is made of plastic if it's the original part. I have seen the teeth break off of the drive gear and the breather gear stop turning. This will screw up the "breathing cycle" on your engine and cause it to "blow oil". Usually, the oil pump locks up when this happens due to the plastic teeth getting in the oil pump but not always. If this eventually turns out to be your problem, have the mechanic or yourself install one of the new S&S reed valve type breather gear replacements. They don't turn at all and work absolutely great. The part is about a hundred dollars but it's well worth it. Solves the old broken breather gear problem that has plauged the Evo engine it's entire life.

There are no "screens" in the Evo engine other than the "tappet oil screen". Just in front of the oil pump is a screw plug that is in the engine cases itself. If you remove this plug, there is a small spring and cone shaped screen that filters the oil prior to it going to your tappets. This should be cleaned every other oil change but it has nothing to do with the oil in your breather.

Now some riders will tell you that if you allow your Harley to sit for any length of time that it will "oil sump" with you. By this, they mean that oil will seep past the check ball in your oil pump and pool up in your crankcase. When you start the engine up, oil will be blown into your oil filter. Not true on your Ultra. The bikes that will oil sump are the Sportsters, Softails, Shovelheads, or any bike that the oil tank is higher than the oil pump on the frame. On your Ultra, the oil tank is on the bottom of the transmission. Your bike will not "oil sump" unless you have a sheared key in your oil pump or the oil has somehow learned how climb. You oil tank is below your pump in other words and oil does not flow uphill.