1992 C–Runs bad after sitting about a month : Kawasaki ZX Forums: Kawasaki Ninja Forum

rossb · 08-21-2009, 08:01 AM

I’ve owned my ZX-11 for over 15 years now and it is always parked in an attached garage that is not subjected to extreme weather. Over the years I always let the bike sit for a few months unused during the winter and I never had a problem in the spring. It would always start right up and run great. All of that started to change a few years ago.

Two years I went to start the bike in the spring and it ran like crap. It would not run or idle at all unless I ran it with a lot of choke. I recognized that the bike was running lean without the choke so I pulled the carbs and cleaned them out. I also replaced the fuel filter next to the fuel pump. I did not really see any signs of dirt or sludge in the carbs, but after I blew out all of the passages and jets and put the carbs back on the bike it ran great again.

I had a similar story last spring, it ran like crap after sitting for the winter. I pulled the carbs, blew them out again and it ran great. At the end of the season I pulled the fuel pump relay, turned off the petcock, and ran the carbs out of gas. I figured that since the carbs were dry over the winter I would be ok in the spring. Wrong….

This year when I went to start the bike I had the same problem, running way too lean and it would not idle. I looked in the tank with a powerful drop light and I did not see any signs of rust, dirt, or sludge. I pulled the carbs yet again and did not see any signs of foreign material. The fuel filter next to the fuel pump also looked ok. I blew everything out, checked my float levels, and put it all back on the bike. The bike ran great again and I tried to make sure I ran the bike every 2 weeks. I put about 800 miles on it this season.

My bike just sat unused for about a month and when I went to use it last night I could feel that it was starting to run badly again. This time it is idling ok, but my part-throttle 2500-4000 RPM range feels rough and low on power. I’m sure the bike will run great again if I blow out the carbs, but this is getting to be ridiculous.

Has anyone ever had a problem like this? I did not inspect my petcock and I did not pull the fuel line that pulls fuel from the bottom of the tank. On my bike the petcock is not plumbed directly to the tank, it looks like a fuel line is plumbed to the bottom of the tank and that fuel line feeds the petcock (I think, I never took this apart).

Are there any screens in the line that plumbs to the tank and/or in the petcock? Is there anything I need to be careful about if I decide to take that fuel line off the bottom of the tank to inspect it? I have a bike week coming up in a few weeks and I don’t want to break anything now so close to the event. It is getting harder to get parts for this bike so I don’t want to risk not having a ride for bike week.

Any ideas? Thanks.

Jet · 08-22-2009, 05:10 PM

I have a c model ZX-11 also but have not experienced this problem. Like you, I often let mine sit for weeks at a time and just keep the battery charged. The only time I've had something like this happen was when it sat for over a year. After running a tank of gas through it with some gas additive to clean stuff out, it worked ok. In talking with some racer friends, they suggested to me that it is VERY easy to get water in the gasoline due to condensation and this settles to the bottom of the tank. Since this is some of the first liquid to get to the engine, perhaps that is part of the problem. I know when I used to fly we always drained water from the wing tanks before each flight. Best way to prevent this is to keep the tank full when you park it so there is very little air in it.

You might also try just changing gasoline brands or putting some fuel saver in it when you park it. You still need to run the engine some to get it into the carbs and float bowl but personally, I see no reason to have to clean the carbs that often. I don't even have to do it that much on my old Amal carbs on my Brit bike. I have heard but can not verify that modern fuels with all the additives in them just don't last very long anymore. Hope that helps.

Respectfully,

Jet

ShadyOne · 08-22-2009, 07:29 PM

Stabil fuel stabalizer is kind to me.

rossb · 08-23-2009, 08:36 AM

I just dumped some Seafoam in the tank. I have a feeling that I'm going to be pulling the carbs again before my Bike Week. I'll have more time to diagnose this problem at the end of the season.

Jet · 09-05-2009, 05:07 PM

Well....I never had this problem before, until today. Went out to ride mine and it started a bit slowly but fired up. I have to keep the choke on all the way or it just dies. Trying to raise engine rpm with the throttle and it completely quits. You can't blip it at all and if you let the choke off any, it dies. Oh well....at least this is the first time I've had to deal with this. And this is after sitting with a full tank of gas too. Man I wanted to take it out today but had to ride the Ducati instead. How did the Seafoam do for you rossb?

Jet

Hammerhead · 09-05-2009, 05:24 PM

Modern fuel begins to turn back into a dinosaur bone 30 days after is leaves the refinery. Try sucking a dinosaur bone through the smallest fuel jet in your carbs and you'll have an idea as to what's taking place.

Jet · 09-05-2009, 06:47 PM

Hey Hammerhead.....I suspect you are correct because I never had this problem before. The gas that is in the tank itself has been there for at least 3 weeks so I figure I'll have to drain the bowls at a minimum but I am going to try an avoid having to pull stuff off. I HATE having to take the fairings and panels off these things to work on them which is partly why I still enjoy the old BSAs and Triumphs. I didn't plan on letting it sit this long which is why I didn't put any fuel saver in it so that is a lesson learned right there. I think I might as well start putting a little in there every time I park it now or keep some carb cleaner in the fuel. Dinosaur bone......good one, would that be Tyrannosaurus Rex or just your average run of the mill Brontosaur????

Jet

zaneyzrex · 09-05-2009, 08:04 PM

old gas, plugged pilots go hand in hand..... one drop will varnish a pilot closed and it wont run without choke....

rossb · 09-05-2009, 10:40 PM

Jet, your pilot jets are clogged, there is no doubt about that.

The Seafoam did not really work for me, mine is idling great but it developed a significant light throttle stumble @ 4500 RPM (strange). I will pull the carbs, remove all of the jets, and blow everything out again and this time I am going to check the screen at the tank output. I'll also check my floats, their height, and the needles/seats. I've done this job dozens of times, it takes me about 2 hours start to finish.

Hammerhead · 09-06-2009, 02:03 AM

Quote:

Originally Posted by Jet

Hey Hammerhead.....I suspect you are correct because I never had this problem before. The gas that is in the tank itself has been there for at least 3 weeks so I figure I'll have to drain the bowls at a minimum but I am going to try an avoid having to pull stuff off. I HATE having to take the fairings and panels off these things to work on them which is partly why I still enjoy the old BSAs and Triumphs. I didn't plan on letting it sit this long which is why I didn't put any fuel saver in it so that is a lesson learned right there. I think I might as well start putting a little in there every time I park it now or keep some carb cleaner in the fuel. Dinosaur bone......good one, would that be Tyrannosaurus Rex or just your average run of the mill Brontosaur????

Jet

Since they were cold-blooded, they probably needed this special bone to....aahhh...well, you know.....

rossb · 09-06-2009, 07:22 AM

Quote:

Originally Posted by Jet

I HATE having to take the fairings and panels off these things to work on them

You only have to take off the side panels, they are very quick and easy to take off. I can actually have the carbs off the bike in about 15 minutes. IMO the biggest pain is putting the throttle cables back together at the throttle grip.

Jet · 09-06-2009, 09:23 AM

Hey rossb or anybody who has done this,

This will be the first time I've ever attempted this. Do you have any suggestions to make the job easier? I was under the impression I had to pull the tank, side panels and rear panels too for some reason. If it is only a 15-30 minute job to get them off, I don't mind giving it a shot. I got to wondering if it might even be possible to blow things out while still on the bike but I haven't really taken a close look at it. I do have the factory service manual and just bought another book solely about servicing carbs so will do some reading first. At least I do have something else to ride in the meantime.

Jet

Claude · 09-06-2009, 02:52 PM

Honestly, 15 minutes to have the carbs in hands is for someone that is extremely fast and efficient and that made it numerous times. I'm pretty sure Ross is in this category. On my side, it is more a 30~60 minutes job.
Both rear side panels, fuel tank and airbox must be removed to reach the carbs.

Jet · 09-06-2009, 04:25 PM

I just got through reading the stuff in the manual and looking at the bike too. I sort of hate I filled the tank when I parked it now. I'm going to put some Seafoam in it just to see what happens but figure I'll have to pull the stuff off anyway. I need the Seafoam for my van anyway so might as well try it. The Haynes Fuel Systems Techbook by John Robinson is the book I bought. Not bad at all to learn how the CV carbs work. Sure am glad I bought the service manuals when I bought this bike too although they could have been better organized and more descriptive in my opinion. For my limited skills, this will be a slow, deliberate process and I may even take some photos just to make sure I put things back the way they should be but it is also a learning experience. Wonder what it would be like for an old fart like me to go to one of the motorcycle mechanics schools these days? Thanks for the advice.

Respectfully,

Jet

zaneyzrex · 09-06-2009, 05:06 PM

Quote:

Originally Posted by Jet

Wonder what it would be like for an old fart like me to go to one of the motorcycle mechanics schools these days? Thanks for the advice.

as a grad of MMI in march 04 i can tell you that you wouldnt be alone as the older people in that school...lots of older guys and lots of younger guys with a few woman thrown in here and thre...

but anyways before you tear these completely down i have a suggestion that has worked for me multiple times on my zrx... every so often i get a plugged pilot and i do this to cure it instead of pulling carbs etc...
i dont know 100% on your bike but i think the airbox is hidden under tank right ? and if you pull the tank you have access to the backs of the carbs right ? do you have a big air compressor ? do you have a nice air nozzle ? when my zrx plugs up a pilot i pull my pods, spray each header with water to figure out which one is not firing at idle and then take the air nozzle and hit the air bleeds at the back of the carb not working at idle.. it will blow fuel up into the carb and air thru the pilot jet etc.. an might stall the bike but no worries. bring the rpms up a bit and hit it a couple times, rap it out a couple times and see if it doesnt start idling on all 4...
i know this is a flat slide carb but same idea, same hole...

Jet · 09-07-2009, 09:40 AM

Hey Zaney,

I was looking at that carb book at breakfast this morning and was thinking of doing exactly what you described. Although I've never pulled the tank before, you are correct that access to the rear of the carbs is gained by taking it off and the airbox. In the pictures in the book, you can clearly see the air openings and I do have a Sears compressor that can give over 120 psi. I've got the little rubber adapter to seal the opening when you blow air in too so should be good to go with that. I am definitely going to try this approach first unless a miracle happens with the Seafoam stuff which I am not expecting to work.

Related to this, I find it VERY disappointing that the local Kawasaki dealer (RideNow) will not even look at this bike. They won't even do an oil change. I bought this thing brand new and have all the maintenance records on it. It is practically showroom new with only 7200 mostly highway miles. She has NEVER been abused in any way and it is precisely because of their attitude towards service that I will not be buying my next bike from them. I was seriously considering a Concours or maybe an FJ Yamaha but if I do, they won't be getting any of my money and I'll be ordering parts over the 'net too. I just bought a new jacket and helmet also, from somebody else.

Thanks for the tip,

Jet

Jet · 09-07-2009, 12:59 PM

Got some problems. Got the panels off, pulled the gas tank and discovered the fuel lines were hooked up in reverse so dumped a lot of gas out on the floor. Well, they are reversed according to the manual anyway. It said to pull the top hose which I did and that is when it started dumping all the gas out of the tank. Looking at the photos in the manual, the outlet of the tank is supposed to go to the bottom inlet on the petcock. Mine was connected to the top inlet.

Here's my problem now. How do I get the airbox off? I pulled the filter (it needs to be replaced because it is torn at a corner) and I've loosened all the external screws and hoses. There are a series of 7 plugs at the back of the box (4 across the top and 3 larger ones across the bottom plus one external screw) that might cover some screws but I can't see into the box to see what to use. Is that how the airbox is attached? If so, what do I need to use to get it off and how do I prevent screws from falling into the carbs with the box still attached? Things were going so well too. Now I'm just ticked off. I can't even get the side panel off the airbox after removing all the black screws because something is still holding it to the carburetor. Only thing I can figure is I have to pull all the rubber plugs and get a tool in there somehow. Thanks in advance for your help.

Jet

Hammerhead · 09-07-2009, 02:06 PM

There are 4 screws that hold the bottom half of the box to the carbs. Upper side of left carb, lower side of 2nd carb from left (accesible by pulling the plastic plug to the left and up from the crancase hose at the rear of the box), and the upper screw of the 3rd carb from the left. The other screw is on the outside lower right of the box and also holds on a wire routing loop. The other 4 screws can remain umtil you're ready to pull the velocity stack plate off the carbs.

zaneyzrex · 09-07-2009, 02:09 PM

jet you figured it out.. pull teh plugs and pull the bolts holding the box to the carbs (10mm w/ 14" rachet w/ extension). just be real carefu (even if ya drop a bolt it wont go down the carbs cause of the slide/throttle plate.... good luck

Jet · 09-07-2009, 03:20 PM

Thanks guys....I got it off. Just due to my tool selection I had to use an 8mm deep socket because my extension wasn't long enough. Used a different flashlight that had a focusable beam to see down in the airbox itself and finally was able to see the bolts. The rubber velocity stacks were making it practically impossible for me to see combined with a poor focus on the first flashlight beam. In fact, the stack on the 1st cylinder was apparently not on exactly right and that is why it was so hard for me to get the socket down in it. Now I can see everything ok and surprisingly enough, the carbs are pretty clean. The number 2 and 3 ones have just a tiny bit of varnish on the outside and 1 and 4 are completely clean. I'm going to blow them out intact on the bike, get a new air filter and just see how it goes. For now, I still don't want to pull them off if it really isn't going to be necessary. At least now I can put things back the way they are supposed to be. This proves what has been said before here about doing your own work rather than relying on an unknown mechanic and their skills and standards.

Would there be any point to spraying some carb cleaner in them now and just letting it sit until I get it back together? To me, they didn't really look too bad at all but if spraying them would help, might as well do it now. Despite my earlier frustration, this is turning into a very good educational exercise for me on water cooled, in-line fours which I have never worked on before. Yes, I'm an old fart and I'm not ready to tackle a valve job yet but this is progress. Thanks again.

Jet