hope some one here can give me a little direction on how to proceed. First a little history, about 3 weeks ago I started commuting on the bike again (zzr 600). I noticed that it was starting hard in the morning but wrote that off to the cold temps and cold blooded nature of the bike. The hard starts continued, it would turn over but not catch. I thought maybe the battery was going south. I am not an expierienced mechanic by any means so excuse my slow deductive process. Got a new battery and problem persisted. Once the weather warmed up I noticed it was running really hot. I checked the coolant and the oil. Coolant was fine but noticed thru the sight glass that oil looked alittle cloudy, not like choclate milk but just off enough to deserve a better look. Drained oil and there was gas in it. Today I took carbs off to look them over and looking into the cylinder I noticed the top of the valves looked like they had tar on the top of them, there is serious buildup. What would be the next logical step? Do I need to pull the valves and what would cause this, would gas seeping thru the carbs be the culprit and if so isn't it unusual for all four carbs to leak at once? Any help would be greatly appreciated, thanks.

 

sounds like you need a complete carb rebuild....and a good cleaning

 

how long has the bike been sitting..... and what year is the bike? oh and welcome to the forum....

 

Hey, a couple questions on the bike.

Is this a California model with all the emmision crap on it?

What year?

I had the exact same problem with mine. same stuff on valves and gas in the oil. After 3 months of trouble shooting, it came down to be the vacuum valve. Nobody, even the experienced Pro's knew what it was, but that was the culprate.

Let me know...

 

Hey, thanks for the quick replys. I'm out looking at carbs right now and to my untrained eye they look spotless. The bike sat for 4-5 months over winter, im in minnesota. Im second owner but original owner bought bike here so no california stuff on it. Bike is an 05 new last spring, so this is only first winter it sat. Has 6000 miles on it and ive put 2k on it since last last fall. What exactly does vacum valve do? Would it cause pistons to flood? Will the crap on valves burn off or do I have to clean them? One more thing is I did a valve check befor I fired it up this year and found 10 of 16 shims out of spec, could this have been a cause or symptom? Thanks again guys.

 

The vacuum valve, from my understanding is for equalizing the fuel level in the float bowls. I believe when the airflow through the air intake on the front of fairing reaches a certain pressure, it opens and applies a constant pressure through the carbs. I don't know if the non-Cal. models have them on. I removed mine.

 

yeah mine has that valve on it. I don't understand how thats gonna get gas to the oil. Yesterday I took carbs off cleaned and inspected them put bike back together. Put new oil in and went for a 2 mile ride, when I got back oil was full of gas again. I did not notice any performance drop while riding but since the bike did not sit with gas in the carbs I'm thinking its getting in while running. I'm gonna do a compression test on monday but if its a piston ring issue I would think it would be pretty noticeable.

 

Here's what you can check to see if the problem relates to what I had. What my bike did was after a 20+ minute drive, and when I shut the bike off fuel would seep out of the float bows into the cylinders. I had replaced the float valves, adjusted the floats, and even replaced the carburetors. Everything I did trying to figure this out didn't change.
Also, after riding I would park it in the garage and hear a breathing noise. What this was happening is when the fule was sitting on the butterflies the fule would bubble up and then suck down into engine, the bike sounded like it was alive and breathing - it was strange.

When I bought the bike, it had most of the emissions removed all but the vacuum valve and vacuum switch. I always questioned this, but everybody stated that they didn't believe that this could have anything to do with it. I found someone who explained how to remove everything else, and it worked. No more fuel dumping ito the cylinders. What a relief, I was changing the oil constantly.

 

That makes sense, I've heard a hissing noise at the gas cap, when I tap it the noise goes away for a little while but comes back. Did you just plug the big hose coming off the carb and the small hose off the cylinders? Did you notice any performance drop?

 

It just came to me, that valve goes right into the valve cover. It could be sucking gas right thru there at any time. I'm going to try that ridht now.