Hi,

Just registered a little while ago and I'm looking for some advice with a problem that's recently developed. I have a 1995 GPZ-1100 (ZX-1100-E) that I bought new. Outside of normal maintenance for a 10 year old bike it's still running strong. Took it out last weekend for a ride and everything was great - but noticed a very strong smell of gas in the garage this past week. Now, when I start it I get an oily gas mixture flowing out of the airbox. After taking the side bodywork off to get at the airbox, it's actually coming out of the bottom of the aibox, from a vent that routes back down to the back of the crankcase. Leads me to believe I've got some sort of a crankcase ventilation/pressureization problem but not sure where to start. Anyone ever run across something like this before?

Thanks.

 

First off is the garage air tight and was it a hot day? If not does your bike have a 1/2" breather tube from some were on the motor going to the air box? It should have one unless you have removed the emmisons equipment. Did you recently run out of gas and go to reserve or prime and accidently leve it on prime or reserve? If a needle seat has gone bad or trash is in a carb blocking the needle from seating all the way and the fuel valve is worn allowing fuel to flow with out a vacum being pulled on the tank then fuel will over flow in to motor or air box .That 1/2" hose from motor to air box is a motor vent and oil mist goes in the air box so the gas is probly just washing the fine oil mist off the sides and bottom of the box. Tap on the carbs to make sure a float didnt get stuck.Also disconect the fuel line from the tank and see if fuel flows with the tank petcoak turned to on or reserve. It should only flow fuel without a vacum pulled on the tank in the prime position.Hope this helps If you need more help Pm for ph# and will be glad to help you trouble shoot.

 

Hey C10,

In answer to your questions:

- Definitely not a hot airtight garage. Fairly nice weather here in Tampa lately and the garage door was open.
- No mods to the emissions equipment, so there's still a breather tube from the top of the head that routes under the gas tank to the airbox. Also has what I'd guess is the equivalent of a cars' PCV valve attached at the head end.
- No out of gas problems or accidental placement of the valve.
- No free flow of fuel out of the tank so don't think there's any vacuum problems there.
- No gunk in the carbs (although I'm sure I'll have to resync them after openening them up!) and they otherwise seem ok.
- The overflow happens with the tank off and disconnected as well, which is kind of odd.

 

C10 is on it.... I'm leaning more to the cabs too.. sound like one of the bowls got caught up and flooded the cylinders. does the oil smell like gas??

 

Good point on oil smelling like gas . does the motor have to much fluid like the gas leaking in now has the motor over filled? Take a good look at the seats in each carb if you have them off the bike. Cheak float heights make sure they are all the same height and refer ther height now to the repair manual if you have one. If not be nice and go by a kaw dealer buy something like oil n filter and ask nicely for the spec on that.

 

Ahh, I think the dim bulb that is my brain may be starting to glow a little bit. Yes, the goo coming out of the airbox does smell like gas.

Here's what I'm suspecting has probably happened. Either got some crappy gas, let the bike sit too long between rides, or something. In any case it probably boogered up the carbs a bit and caused a flooding condition that has overfilled the crankcase. At this point I've probably corrected any carb problem just from the good cleaning (plus no parts were binding, etc). but I think the crankcase is still overfilled. I'll pick up some oil change supplies and see if getting the crankcase back to the right level straightens things out.

 

OK, how pitiful is this - almost 2 months and I'm just getting time to work on this again.

But, I have made some progress between February and now. First of all the crankcase was definitely overfilled with a gas/oil gunk mixture. Draining and doing an oil change has corrected the overfill problem, and now when the bike is running it doesn't spew the mixture out of the airbox anymore. I realize that there's probably going to be some fallout from getting gas into the bottom of the crankcase but I'll pick away at that as it comes up. Second, I think the crankcase overfill problem was caused by a fuel tank valve that was going south - sometimes it would shut off correctly, sometimes it would keep flowing gas out of the tank. Replacing the valve fixed that issue.

So, after all that now what I've got is an inline 4 that's basically running like a big twin. I can hear that all 4 cylinders aren't firing and I'm getting gas flowing out of the carburetor vent tube on the left hand pair of carbs (as you're sitting on the bike) when the bike is running. At this point I'm thinking stuck float/stuck needle/clogged jet. Any thoughts as to whether I'm on the right track?

 

Sounds like your on the right track. I would pull the carbs and clean them. Also check to see if the floats are taking in gas sometimes they go bad. Be sure to recheck float level.