fz600 1987

[toastie]

hi can anyone help,bike starts,runs but oil comes out of crank case breather hose, canrnt seem to stop it any ideas ? thanks toastie

 

[Tremulant]

Sorry, I'm no mechanic so I won't be of any help, but please post some pics of that classic bike!

 

[Fahren]

Yay hello bro ( toastie is my younger bro) we both have 1987 FZ600's..he's done a great job so far on this classic, it was a none runner but after a little work he manged to get her fired up and it sounds sweet! problem is the crankcase breather pipe that fits onto the bottom of the airbox has decided to spew out oil when the bike is running...im thinking its either a blockage somewhere else within the engine i.e. oil breather pipes etc or the oil pump...this had only just started happening though...it was fine b4 that

and yes we will post pics once we get the spray jobs finished..

anyone else any ideas why this might happen?

 

[The Toecutter]

Blow by....if the piston ring gets stuck or galded to the piston the compression it's trying to make leaks back into the crankcase...do a compression test to verify all the cylinders are up to snuff... :rockon:

 

[xj750_Pete]

Possibly too much oil? I've never had oil spewing out of the breather, but I've had gasoline flow out of it because of stuck float needles in the carb float bowls.

 

[Fahren]

right i had a look at my Bro's FZ600 today and he showed me what was coming out of the side crankcase oil plug...it was definately a mix of petrol and oil!!!

now the question is how is it getting in there? if the carb floats were stuck open then surely the fuel would spew out of the carb overflows?
the only other thing i can think of is these bikes have 2 pipes coming from the pet tant one is the main fuel line and the other looks like a breather pipe which comes off the petrol tap and attaches to one of the inlet rubber tops just forward of the carbs...(there is another pipe that comes from the tank but that only drains to the floor)....could this secondary pipe from the fuel tap be the cause ?

 

[badrad600]

The second little tube is to operate the vacuum shutoff diaphram in the pet****. I agree with others check your needles and to a compression test.

 

[toastie]

thanks for all your help so far,after some more diggin about there seems tobe petrol mixed with the oil in the crankcase could this be a sign of worn piston rings.:Flash:

 

[The Toecutter]

During normal operation, a small amount of unburned fuel and exhaust gases escape around the piston rings and enter the crankcase, referred to as "blow-by". If these gases remained in the crankcase and condensed, the oil would become more diluted over time, decreasing its ability to lubricate. Condensed water would also cause parts of the engine to rust. To counter this, a crankcase ventilation system exists to draw fresh air in from the air filter and expel the gases out the PCV valve into the intake manifold. In a non-turbo engine, the intake manifold is at a lower pressure than the crankcase, providing the suction to keep the ventilation system going........ If an engine is damaged or enters old age, gaps can form between the cylinder walls and pistons, resulting in larger amounts of blow-by than the crankcase ventilation system can handle. The gaps cause power loss, and ultimately mean that the engine needs to be rebuilt or replaced....... ( Symptoms of excessive blow-by include oil being pushed up into the air filter, out the dipstick, or out the PCV valve)

 

[sempul]

The second little tube is to operate the vacuum shutoff diaphram in the pet****. I agree with others check your needles and to a compression test.

LOL i love that it blocked the c0ck in petc0ck lol

 

[Fred]

now the question is how is it getting in there? if the carb floats were stuck open then surely the fuel would spew out of the carb overflows?

On those carbs, I don't believe that there is an overflow.

So what happens is that when they overflow, the gasoline flows downhill into the engine's intake, then washes past the piston rings into the oil.

For a sure-fire fix, I'd replace the following.

Carb floats. (4 needed)
Float needles. (4 needed)
Float bowl gaskets (4 needed)

And a petcawk rebuild would not be a bad idea either while you're in there getting covered in gasoline.

Oh yeah, change the oil before you run it unless you want to ruin the engine.

Fred

P.S. I have a service manual for the 85-87 700 and 750 Fazers. If you need and info out of it, send me a PM and I can scan pages for you.

 

[sackcheck]

I had the same Problem when I bought my '89 Radian (same engine as the FZ) The problem was the the floats were stuck and the pet**** was worn out so after you parked it the gas would drain thru the carbs, into the the airbox and thru the engine case breather tube, and then the case would fill with gas and the next time u start it up it would pump oil and gas back thru the breather tube and out the air box.

So a simple carb maintenance took care of that.

A couple other tips, clean one bowl at a time, take the floast off pull the neadle valve and needle valve screen and clean,

And make sure you get a fuel filter and and try and seal your tank, It will save you alot of Carb hassle in the future.

 

[aquaracer]

I have the same bike and the same thing happened to me. I took off the oil cap and seen no oil in bottom of crankcase (forgot about crankcase site glass on side of motor) and added oil to it. I started the bike up and took it for a spin. About 50 feet down the road I noticed that the rear tire felt loose when I gunned it. I looked back and seen oil all over the place. Soooo, drain some oil out and check the site glass on the right side of motor for propper fill and you should be good.:thumbup: