FZRSupport: the FZROnline Archive

Hello everyone. Looking for some advice. I'm new to motorcycle ownership and maintenance so don't get too technical if possible. I have an 88 FZR600. Got it as a starter bike and it has been a lot of fun. 2 months and 1000 miles no problem. Until last weekend was on highway and pulled over at gas station, as soon as I stopped QT+ of oil came pouring out the bottom. Cleaned everything up, pulled fairings but couldn't see obvious source. Added QT of oil and nursed it home no problem, very small amount of oil dripped after that. Rode around block, to and from store, etc.....nothing. Get up to speed on highway and it dumps oil. Where should I start looking? Any suggestions would be greatly appreciated. Thanks!


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Oil leaks should be easy to find on a Japanese motorcycle.

You are filling it to the marks on the sightglass and not above the glass completely when the bike is stood level and upright.?

Unless a casing is cracked or loose it can only be from a seal or gasket or........I'll get back to that bit later.

The machine needs to be thoroughly clean to trace the leak; oil will migrate from it's source and lead to wild goose chasing.

It does point to one place though....the later bit .

Is the crankcase breather connected to the airbox and is the airbox drain pipe still connected.

It seems strange that the leak only appears after a brisk workout.

Has it used, rather than leaked, oil previously ?

If the engine is worn, at low rpm and light use ; the piston blowby can be managed by the crankcase breather system.
When used at high rpm ; the oil is forced by blowby up the crankcase breather tube to the airbox.
The engine usually burns most of this though and the smoke will be apparent.
Because there is a well at the c/c breather inlet to the airbox the oil may be building up there and be prevented from draining correctly down the drain tube by inlet pressure of a fast running engine.
Once stopped the air inlet pressure is low and the oil drains down the airbox breather tube.
That tube should have a one way valve....many are missing.

Check inside the airbox for lots of oil.
If you can find the airbox drain tube...use a catch bottle on it for a test.

It is more than likely just a gasket somewhere though.

As all mechanical problems....diagnosis is a piece of piss if the machine is infront of the mechanic.....remotely by a description on a screen is a different matter. !

Thanks for the education/lesson/suggestions. Update: pulled lower apart. No oil in pipes, no obvious signs of leaking or fractures in block. All oil was concentrated to bottom of engine no residue on top. Removed pipes, radiator, oil filter, bottom pan. Cleaned everything real good replacing filter, O rings, gasket and pressure relief valve (spark plugs and air filter while I am at it.). Hope to have it back together and give it a good workout this weekend and see if that solved my problem. Anything else anyone can think that I should check while I have it apart?


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