1980 kz440 Fuel leaking out of exhaust and foggy oil

Hello, I’ve had this 1980 kz440LTD for many years occasionally working on it but I haven’t got it running right yet. I finally made an account on the forum because I thought I’d need as much insight as i can get before I keep running this thing and damage something. So I just rebuilt the engine because the cylinder walls were gouged/scratched (mostly right cylinder). I deglazed the walls until I couldn’t see any gouges then I put new pistons and rings. Looking back now I wish I had sleeved them to add longevity. I took the engine head to a shop to get a valve job and to recut the seats because I had swapped one valve guide that I damaged. They checked compression and all. This was my first rebuild and it was a learning experience.. but I feel decent about it and thought it should at least run better than before. After putting it all back together I my compression read about 130psi and the spec from the manual is between 109psi-156psi. I won’t go too much into the engine rebuild unless someone is thinking that’s where my issue is.

Upon my first start up I did miss some things and it ran badly as I saw fuel leaking out of muffler and oil leaking into crankcase. I Took the carbs apart and my main jet was entirely unscrewed in the float bowl. So I got that corrected and cleaned the carbs good. Another thing was the intake boots were not clamped so I got those on tight. Lastly I checked my valve clearance and I had the exhaust valves adjusted way too much so I corrected that. Then I also replaced contact breaker and set timing with a light. I thought all this would fix things, but I still had the gas leak out the exhaust and oil in case after trying doing all that. It ran better, but still would get bad as it warmed up and seemed to rapidly accelerate without me touching the throttle until I had to just kill it. I hear often times it is the float needle that can cause too much gas/uncombusted gas. But it is a practically new needle and I inspected mine.

Here are some things I’ve done since my last time running the bike.
–improved exhaust seal where it mounts to engine because when I was mounting the pipes onto the header one stud broke off so I think it wasn’t sealed enough. I found out I could replace the stud so I will be tight and against the gasket next time I start it.
–I checked my float bowl height and the right side bowl was a little low. So I adjusted the float clip and now its fills up more.
–I checked the spark and it is blue. I thought the spark was weak but maybe it’s normal and at least I could see it without turning the lights off. (Also brand new ignition coils and relay starter)
–I replaced the needle on my carburetor slide because the last one looked bent.
–double checked my valve clearance and I did add slightly more clearance in the exhaust valves because it was a little hard to slide the gauge in there. But it was close.

All the symptoms of how its running seem carb related to me because it seems like it’s just running rich unless something else is causing the gas to not be get burned all the way. 

The only thing I can think of is that maybe the jets in my carbs were supposed to be for pod air filters, because I got the bike from someone who new nothing about the history and it didn’t come with the stock airbox or air filter so it’s possible it was rejetted for pods and that throwing it off. I have the stock airbox and a 3D printed air filter that matches stock. Here are the jet sizes I have in my bike in case anyone knows what the size stock is.
Primary main jet- 62
Secondary main jet- 88
Pilot jet- 35

Any insight is much appreciated. Thank you

From this table it sounds like you have the stock sizes of the jets. (for use with air box)


If fuel is indeed leaking out of the exhaust ( or is it just condensation in the pipe that you are seeing?) and it appears that fuel is in the crankcase then it would to me appear that fuel is not being stopped by the float valve or the level is way too high. If that is the case I would suggest to drain the oil, solve the overflow issue and then put new oil in and try to start it again.

I would also ask what is the voltage to the coils, it needs to be close the full battery voltage, if not then the spark may not be sufficient to burn off the fuel and some gets pushed into the exhaust pipes.

Thanks for the advice and the reference table. I was pretty sure I checked the fluid that was leaking out by touching and smelling. I checked my float valve and it looks fine and it’s new. I have tried to clean some brown spots of the brass sleeve guide for the float valve with carb cleaner and qu-tip, so and it looked the same after, so I think that wasn’t the problem. I also checked my float bowl level with a clear tube and it was correct and assume that would be off if the needle wasn’t working right.That’s a good point to test my ignition coils. I  actually tested my ignition coils with a multimeter and got “0” ohms when I tested with spark plug boots on, but I got the right reading with boots off touching direct to my leads. I replaced the boots and got about 22 ohms. I’m hoping the bad boot was the cause of gas not igniting and hopefully led to my fuel going through to exhaust pipes and crankcase. I’m going to hold off on starting the bike until I’m sure this was the cause. I tested the voltage from right after my starter relay and it was the same as my battery (12.7). But when I check voltage at the  ignition coil connection it was at 10.92 V. I read that in some cases that is reasonable voltage drop, but i don’t know about this bike specifically. So right now I’m trying to figure out if that’s normal for my bike or if it is a problem with my wires/connections. 

Izzyrider1015 wrote:

Thanks for the advice and the reference table. I was pretty sure I checked the fluid that was leaking out by touching and smelling. I checked my float valve and it looks fine and it’s new. I have tried to clean some brown spots of the brass sleeve guide for the float valve with carb cleaner and qu-tip, so and it looked the same after, so I think that wasn’t the problem. I also checked my float bowl level with a clear tube and it was correct and assume that would be off if the needle wasn’t working right.That’s a good point to test my ignition coils. I  actually tested my ignition coils with a multimeter and got “0” ohms when I tested with spark plug boots on, but I got the right reading with boots off touching direct to my leads. I replaced the boots and got about 22 ohms. I’m hoping the bad boot was the cause of gas not igniting and hopefully led to my fuel going through to exhaust pipes and crankcase. I’m going to hold off on starting the bike until I’m sure this was the cause. I tested the voltage from right after my starter relay and it was the same as my battery (12.7). But when I check voltage at the  ignition coil connection it was at 10.92 V. I read that in some cases that is reasonable voltage drop, but i don’t know about this bike specifically. So right now I’m trying to figure out if that’s normal for my bike or if it is a problem with my wires/connections. 

That is far from reasonable  !! you should have no more than 0.5v drop from battery to consumer. Also your coil readings should be between 2-4 ohms on the primary side and approx 15k ohms on the secondary (check the manual for specific spec for your bike) there is a link in my signature to the electrical fault finding guide I wrote, check out resistance faults

Thanks for the information, Wookie. The primary test was right on 4ohms, and the secondary was 12.9 ohms on the coil leads with is in spec. but the boots add about 5 ohms each because of resistors or something like that, so with boots it’s 22.9 ohms.

I went to the Forums FAQs and saw that you wrote out The Electrical Fault Finding Guide, but the link wouldn’t work for me and just say not found. It would be super helpful to go through it so just let me know if you know how I could view that still!
Thanks!

I went through the obvious things so far like fuse connections and ignition switch, but I just need some time to dive into it!

I do not mean to speak for Wookie, but you can find the doc in the filebase here    kzrider.com/filebase-alias/category/28-g...l-electrical?start=5

Keep in mind that you have to be logged on to the forum to have rights to the filebase section

Just circling back into the forum after making some progress. I got busy with and had delays. it was very helpful for me to go through the electrical guide, as I was able to pinpoint which wires were bad leading to my ignition coils. And I improved my voltage a lot with just cleaning but I was still too low with the kill switch off. It appeared the power wire was actually too corroded so I chose to run a new wire from my battery straight to my coils to bypass the bottle neck of my bike by making a relay circuit rather than trying to replaced old wires and solder to my kill switch. This gave me the full voltage. So I was ready to move past this. I bought new spark plugs and tested my voltage and spark before proceeding. I changed out the gas-fouled oil and filter. And I got the bike started. It ran great, it was still chucking blue smoke because of the rebuild I thought, also oil in my exhaust pipes from before my piston rebuild. Hopefully that goes away… I took it on a two rides around my neighborhood about 10 minutes each, and I thought to check my oil and to my surprise the oil appeared foggy/bubbly. I removed the cap to smell the crankcase and it spelt like gas. So did my new spark plugs and they also had black wet residue on them. So the voltage increase to my coils didn’t fix everything. But now after thinking about it. I got Walmart battery that was 2 years old out of the box (screw those guys) and it sits at 12.4ish volts, but my with my new ignition coil wiring I have 12.4ish right at my coils. I don’t know how fresh my battery must be for this bike, so let me know if I’m unaware. my petcock seems to be fine. It is not the stock petcock with a vacuum line, so I left it in the off position to test that it’s functioning and I saw that it doesn’t drip when left off. Though I thought maybe  left the fuel on while sitting once, but I don’t know if that is enough to foul my oil this bad cause I’ll need to replace my oil already after 20 min of running the bike total. my choke is operating correctly. My float needles are new and don’t show signs of wear on the rubber tip and the spring pin is working.both my floats seem fine when I did a 15 min float test with a clear tube to see my level and both float bowls are just a bit below the mating surface, which I think is in spec.My pilot screw is turned out 2 & 1/4 turns.

All my carb test leave me wondering how it’s still rich and getting fuel into the crankcase and spark plugs. I did clean the carbs before winter and i only  use ethanol free gas and added stabilizer over the winter. Plus I gave it a good inspection right before this trial of running the bike and replacing the oil, so nothing looked gummed in the carb. I guess I’ll double check that cause I’m puzzled. 

Looks like you got a mess on your hands  When you took it for a test ride did it feel sluggish in any rpm range or low on power in general? My kz440 can fairly easily get up to 80+ mph. When you replaced the jet needle did you use the oem specified needle (N02A or N03A depending on model)? Did the needle that you used have 5 slots for a c-clip or no adjustability? 

Just to clarify to me, was it fuel or oil in your exhaust? Just asking because you contradicted yourself there. Do you have a hole in your exhaust where the fluid is leaking out of or is it at the header that its leaking? Finally, did you still have oil in your exhaust after those rides and do you still have blue exhaust gas?

Whew, that was a lot of questions. My main concern right now is that when you brought your head in to get the valve job they did a bad job with replacing the valve stem seals and they're leaking. As for the gas in the crankcase, I am pretty lost on that one. Usually gas leaks into the airbox and down the crankcase vent. Good luck!
 

bound wrote:

Looks like you got a mess on your hands 

When you took it for a test ride did it feel sluggish in any rpm range or low on power in general? My kz440 can fairly easily get up to 80+ mph. When you replaced the jet needle did you use the oem specified needle (N02A or N03A depending on model)? Did the needle that you used have 5 slots for a c-clip or no adjustability? 

Just to clarify to me, was it fuel or oil in your exhaust? Just asking because you contradicted yourself there. Do you have a hole in your exhaust where the fluid is leaking out of or is it at the header that its leaking? Finally, did you still have oil in your exhaust after those rides and do you still have blue exhaust gas?

Whew, that was a lot of questions. My main concern right now is that when you brought your head in to get the valve job they did a bad job with replacing the valve stem seals and they're leaking. As for the gas in the crankcase, I am pretty lost on that one. Usually gas leaks into the airbox and down the crankcase vent. Good luck!

 

Yeah it feels like I got a mess here… on my test ride I didn’t notice any sluggish response just maybe a couple hesitations when starting from 0 mph but that seemed minimal and only a few times. This is my first time actually riding this bike but I’d say I got to 40 mph pretty easily.

the Jet needle I got with my rebuild kit is N02A, which matched the ones I replaced. Only difference is my old needles were slightly bent. It doesn’t have the c-clip/notches or any adjustability.

To clarify for the gas and oil in the exhaust. I don’t have oil leaking into the exhaust but I had it dripping out of my exhaust drain-holes before I rebuilt the cylinders and valves so my thought was that I still have oil trapped in the mufflers from that which is contributing to the blue smoke. And I’m hoping another reason for the blue smoke is my pistons rings still seating. So after my rebuild is when I had gas leaking out from the exhaust drain-holes. And then I fixed my voltage drop issue at my ignition coils and I haven’t had unburnt gas pouring out of the exhaust since, but apparently there is still unburnt fuel leaking through just maybe less than before. So to answer that last question I do still have a good amount of blue smoke coming out of the exhaust but I’m hoping it’s partially  because it hasn’t gotten hot enough to burn out the old oil that got into the mufflers from a long time ago. 

I won’t rule out the bad valve job being a culprit for now. My airbox has no sign of fuel but it looks like the drain hole on the bottom of the airbox has been sealed so I might try to get that hole back.

I took the carbs apart tonight, and comparing that float valve I have in there with the last one it looks slightly different. Mostly just the springy button on top appears to be longer, stronger, and a different color. The runner part looks like it’d work the same but still looks slightly different. I don’t see how it’d be a problem given my float test showed the correct level. But maybe I’ll have to order new ones or just use my old ones since they look fine. Maybe it’s when the engine is running that float valve struggle from vibration. Idk. I’ll try to upload my pictures I took of them. I got the rebuild kit off eBay from a Japanese seller called “Crusinimage” so maybe some of the kit is wonky. 
 
 

I cannot say whether cruzinimage carb parts are of good quality but generally people here have had good luck with their engine parts. The cruzinimage float valve looks like it should work fine. The extra length for the spring should be compensated by checking the fuel level (which you did) and if they werent sealing you would know.

Im a little worried that the previous jet needles were bent  How does that happen?!?? PO must've learned to fix things with a hammer... what worries me is that since the jet needle was damaged, the needle jet is also damaged, which could be causing it to run rich.

My only other hypothesis at this point as to why your plugs are caked and fuel is getting into the crankcase is because you have poor combustion for some reason causing it to flood and fuel is getting past the rings. Reasons could be that it needs valve clearances checked, poor compression, or because your points need to be sorted through for your ignition.

I would think that the most likely reason is the points need to be looked at. Im pretty sure 1980 models still had points. while you're in there, make sure to lubricate the governer and be sure that it can turn freely since that could mess with your ignition curve.

If you have the carbs off the bike at the moment and want to check if the float valves are doing their job then turn the carbs upside down. Remove the bowls and blow into the fuel line. By mouth. Not compressed air. If all works as it should then it takes a lot of puff to lift the float. If the valve is not sealing then you will know pretty quiclkly.. probably dirt in the seat in which case a Q tip dipped in Brasso will polish it up. Rinse off with carb cleaner and test again