Kawasaki Sportsbike Riders Club - Australia - Online Forum

Hi guys

The GPX has a fairly generous amount of oil dripping from the airbox. A regular eye on the oil and there are no problems, except the annoying puddle in the driveway!

I understand that this is a result of blow-by past the rings, through the breather and into the airbox, from where it drips when the bike stops. So, I can fix it with a new set of rings, but that doesn't sound cheap. I don't see the point in an engine rebuild as all it will do is stop the leak - it's not noticeably down on power or blowing smoke at all, and it's just my daily runabout.

The other option is rerouting the breather into a catch can... has anyone else had this problem and solved it through either of the two methods?

Shifty wrote: I understand that this is a result of blow-by past the rings, through the breather and into the airbox

You could try a heavier grade oil, wont matter if the donk is that rooted. Or you could try and depressurize the crankcase by some other method like drilling a hole in the filler plug say. Take the pressure out and the oil wont get driven up the breather? Or simply put a catch container on the end of the drip pipe that leads from the airbox and then empty it at your leisure

How is the idle, Shifty?- it is common for GPXs with the problem you describe to have a fluctuating idle- the fix is to fit a crankcase breather- like a little air filter so that the airbox is disconnected from the crankcase- block off the hole in airbox left from the hose too.

It could be as simple as too much oil in the bike and its blowing out the breather into the airbox.
Check the oil level and make sure its in the middle of the window..

If your rings were shot oil would be getting to the combustion area, burning and blowing smoke out the exhaust..

your not measuring the oil with the bike on the side stand are you?


my old CBR250 used to get a fair bit of oil in the airbox, i just took the pipe off the airbox and plugged up the hole in the airbox... a little breather filter would have been nice, but meh

Shiftys right, GPXs and ZZR love blowing oil up the breather tube, even when in perfect running order.

Running a catch can worked fine for our GPX, and we just returned the oil to the sump every few weeks.

MadKaw wrote:
If your rings were shot oil would be getting to the com
bustion area, burning and blowing smoke out the exhaust..

usually! But if the oil rings are ok and a compression ring is sour then combustion gasses can get driven down and pressurize the case, hence the overflow

Well, as it turns out, the oil level was right, but the reason for the drip was too much oil.

"What!?" I hear you say... the oil level was fine.. but there was over an inch of oil in the airbox!! I've drained this and the leak has mostly dissipated. As stated though it's a bit of a GPX trait so I'll have to look at something else to stop the occasional drips I'm now getting.

What did u do to fix this? I got my bike tested and its compression is fine and not blowing smoke, but exhibits the same problem. So far the mechanic has just stuffed the crankcase breather hose (the one that connects crankcase to the airbox) with some gausse, but now the breather hose isn't sealed properly and so it leaks oil all over the crankcase lol.

My problem is definately not too much oil as I drained it and only topped up 1.5L (vs the required 1.9L), its a good bike I just wish I didn't have this oil leak issue.