Do I need to clean my carbs??? (and gas tank rust question)

[kawasakininjazx6]

Hey, I own a 1992 Kawasaki ZX-6 D Ninja, and im having a few issues.

 

-First issue would be I have the occasional backfire, but not often at all.

-Another issue is when I start my bike it will idle for a short time, then progressively loose RPM's until it dies. I need the choke to keep it going. (But after about a min of keeping it above 1000 RPM's it idles fine) *this is the main thing im wondering about*

-Last would be that it seems to have less power accelerating than my friends bike, which is the exact same model, but 1 year under (1991).

 

Little history: just bought the bike off a friend, and he said it was sitting for about 3 months, worked great before he let it sit.

 

Is this something that I can take care of myself (aka cleaning the carbs myself?) and if so, anyone know where the carbs are located on my style bike?

 

 

----

Another question: There is a little bit of visible rust in the bottom of the gas tank, but it appears nothing really floating around on the bottom. Is this something I should get taken care of asap?

 

And again, is this something I can do myself? Ive read a few forums on this also, dosent seem to be too hard. But whats the best way?

 

 

Thanks alot for everyones help, and input!

[lwfc]

better to bring it to a trusted mech..

[kawasakininjazx6]

Well, the key word there was to do it myself. Im a bit low on cash right now, so it would be best to see if I could figure out my possible culprit before I went to the mechanic...

So anyone have any actual help?

[kawasakininjazx6]

Well, today I went out with it and I noticed it was idleing really high when I had the cluth in, near 5000 RPM's. So I pulled into a gas station to tone the idle switch down, and it started normal, and idle'd normal in neutral, but once I put it into first, it died. (I may have had the kickstand down, and i heard my bike might have a kickstand switch?) And then after a few trys no lights or anything came on when I put the key to the on position. So I had someone come try to jump my bike because I thought it was the battery, but what do you know, put the key in to move the bike, and it started up normal. And then went into first and it was fine (this time without the kickstand, so I assume it was the kickstand switch before). On the way home I noticed a lag in the acceleration (carbs clean maybe?). And then finally when I got home, same thing when I had the clutch in, very high RPM's.

 

Any idea what the problem could be? As soon as I get money I will go to a mechanic. But would really like to have an idea what is wrong with it.

[danielsin2]

It sounds like your carbs need to serviced and retuned.

Try fitting a petrol filter to prevent the rust in the fuel tank from entering your engine.

[kawasakininjazx6]

thanks alot for the response, i did think it might be a carb problem.

My friend just told me that its normal for a bike to need to warm up with choke? Is that true? And ya it looks like I was trying to put it in first gear not thinking about the "switch"

 

Ok, so obviously im new to biking ^^ lol

So where would i get a motorcycle fuel filter (petrol filter) at? I know autozone carries some things for my bike, like headlight, but would they carry this also?

 

Again, thanks so much you guys are life savers.

 

**Edit**

Just noticed after riding it, I have a bit of gas on my jeans at my left knee...

Know anything about what that could be?

Edited May 20, 2009 by kawasakininjazx6

[newcomer]

I'd put my money on the carbs. Sound like you have a clogged pilot jet. Tear down your carbs and clean the pilot jet, main jet, main jet holder, transition ports, idling circuit, basically any tiny holes in your carbs. They are there for a reason!

 

The little holes in your carbs usually gets clogged if the bike sits for sometime. If your pilot jet is clogged, this will cause start up issue, thus resulting in you using the choke. A bike in good condition will never need the choke to start. The choke is there to warm your bike faster and without playing with the throttle. In fact, over reliance of choke during initial start up will cause more harm than good.

 

Yes if you have the side stand down, putting the bike in gear and trying to gas it will cause the power to cut off because the side stand does indeed have a kill switch.

 

To access the carbs you need to remove the fuel tank and airbox. You need to remove the air/fuel hoses, and choke/throttle cables. Looses the screws on the clamps which are located between the carb throats and intake ports. Proceed to wrestle the carbs out, it may be extremely hard. I use a crowbar to gently pry it at the sides. Take care as the carbs are made of aluminum.

 

Check that your airbox has all the necessary hoses attached to it, and the hole at the back of the airbox is sealed, if there's a hole, whose only purpose is to access a screw to remove the airbox unit. Check your ram air intakes are not clogged with mud or insects whatever. This paragraph is an often mislooked part which affects idling and throttle response.

 

Btw is your clutch operated via cable or hydraulic? If cable, check it's routing and that it's not pulling on the choke or throttle cables that might open up the throttle valves. I suspect it's this as shooting up to 5k rpm sounds extreme.

[kawasakininjazx6]

thanks so much for the response, i recently ordered a haynes manual specifically for my bike so id know exactally what to do by picture to go along with what your saying.

 

And I will def. try everything you have suggested.

 

Now, the 5000 RPM thing I found out (i pretty sure cuz it hasnt done it in about a week) is that i had set the idle screw way to high when i started the bike (tried to make idle stay at 1000 RPM but it never did) while is was cold. Turned it back down and it hasnt done the same since.

 

Now i just notice that it wont idle and eventually dies, when I drive it and come to a stop i have to constant on the throttle when it goes below 1000 RPM's to keep it alive (rather annoying). So from all I hear its the carbs and ill try them within a week and report back.

 

Now the last thing ive noticed, is that (from what i can see without taking the gas tank off) gas seems to be seeping slowly out of the black air box (i think its the air box or w/e the real term is for it) when im riding. That also has to do with the carbs?

In conjunction with that, i notice that when i accelerate in 1st gear, its very slow for the first 5000 or so RPM's then once it gets above, it really takes off. Is this normal? or another carb problem (aka air/gas mixture issue?)

 

Thanks for any and all replys! Dont know what id do without forums.

[stsoh]

question: how did u balance all 4 carbs without something like carbtune (vacuum gauge tool)?

your off-balance carbs will not give smooth idle n power.

one piston will draw more fuel than the other.

 

read this, it will guide thru:

http://www.singaporebikes.com/forums/showthread.php?t=68870

[kawasakininjazx6]

I havent done anything to the carbs yet, and dont plan on it until I get the manual. I bought the bike how it is now.

[newcomer]

In fact I have a carbtune on the way from UK. Can't wait to see how well it works.

 

Well regarding synching the carbs, I learnt a nifty trick from a msian mechanic. He taught me to use a piece of newspaper to slide under the throttle valves. Adjust the three synchronizing screws until all 4 throttle valves barely allows the piece of newspaper to slide under it, much like how you would use a feeler gauge. It only needed veeeery slight adjustment should you have the fortune of plugging a vacuum gauge in. Btw, only extremely unbalanced carbs will affect your idling.

 

Yes a Haynes manual is invaluable in troubleshooting your problems, although it'd be much better if you use it in conjunction with the Kaw factory manual.

 

Glad you found out the cause of that 5k rpm idling. As mentioned, your idling problem is 99% caused by clogged pilot jets. Because the pilot jets control idling and acceleration from close throttle, clogged pilot jets will cause a lean mixture up to 5k rpm on your bike. Lean mixture = want to die want to die and no low end power. After 5k rpm, (about 1/2 - 3/4 throttle pull I think?), the main jet starts to take over and pump more fuel into the cylinders, thus you feel a sudden surge of power.

 

The holes on the jets are extremely small, you can only clear them by using something very small like a steel brush wire. Spray some carb cleaner into the jets before poking the crap out of them. After you have done that, confirm the passages are clear by blowing compressed air into the pilot jet and feel the air escaping from these 3 points:

 

1)Main airjet

2)Idling circuit

3)Transition ports

 

Alternatively, you may pour gasoline through the pilot jet and check the passages are clear. While you're at it, cross check your jet sizes against the factory specs, float height, diaphram for holes, etc. You might as well do a thorough cleaning since you're into the carbs.

 

Now inspect the two air tees at the top, between the two pairs of carbs for air leakage. Usually if they rotate without much effort, it means the orings need changing. Inspect the other two fuel tees at the bottom, between the top pairs of carbs for fuel leakage. It's advisable to do this with the carbs out of the bike, as any leaks might flood your cylinders(big nono). Rest the carbs in a position like you would on the engine, and gravity feed fuel into the hose that connects to the two fuel tees via a container. Wait a minute or two and see if fuel leaks out from the fuel tees. Sometimes it may start to leak madly from the fuel tees but then stop after a few minutes. This is because the o rings in the fuel tees are reacting to the petrol and thus expands as a result, effectively sealing it. Unfortunately you will still have to renew the orings as this is an indication that the orings are damaged. Too bad the manual doesn't tell you all these.

 

If fuel is seeping out of the airbox, you have a major leak in the carb. STOP riding the bike as flooding the cylinders will cause it to hydrolock, and this usually means an engine overhaul should the motor starts. First, check that it is indeed fuel and not EO from the breather tube which is connected to the airbox. If it's fuel, one or more of your carbs are leaking either at the float needle, or the oring in the float needle seat is fubared. Don't be surprised if they're totally squished, hardened and cracked. Anyways, both will result in the carbs overflowing petrol in the airbox AND the intake ports. The overflowing petrol which goes into the intake port will cause a rich mixture and the unburnt petrol will be pushed back by the exhaust pulsating pressure and fly back into your airbox also(this is also called a backfire). Again, test fuel leaks with the carbs out of the bike. Any overflow will be apparent as you can see petrol slowly leaking out from one of the brass tubes located at the carb mouths. Make sure that the float needle is free to rotate and easily slide up and down in the valve seat and that the needle rubber tip is in pristine condition w/o ridges or obvious wear. Place the floats in petrol and make sure they really float. Push the floats up and down and make sure they are not sticking. Check the float needle plunger for spring tension. Check the carbs and valve seat filters for any dirt or rusts. The needle tips do not tolerate the slightest amount of dirt/crap in the carbs. Take extreme care in removing the valve seats should you need to renew the orings. They're very soft and deform easily if you use a plier to take them off. If they deform, it will also cause the float needle from returning to its closed position in the valve seat. Removing the valve seats may be tricky if they have already set in. Consult a mechanic experienced with bike carbs should you have difficulty. Otherwise, you can try this method at your own risk. Look into the valve seat and see if you can find the gauze filter. The tiny gauze filter is retained by a plastic to the valve seat. There're four notches around the diameter of the plastic. Leverage the filter out of the valve seat carefuly by picking at the four notches evenly. Once that is done, use an improvised hook to pull the valve seat out. I use a small punch and give a few sharp taps around the valve seat to break the bond that has set in between the oring and carb body, then pull them out with a plier as gently as I can.

 

HTH. Damn I need to sleep already.

Edited May 28, 2009 by newcomer

[kawasakininjazx6]

Well, at the moment all that is foreign language to me lol until i get my manual. But im sure once i get the parts named ill know what to do.

 

And im a bit worried that you said hydrolic lockup or w/e... sounds expensive to fix, and its not something I want to / willing to do on a $2000 bike :/ this thing allready costing alot more then I anticipated.

 

Ive only put about 30 miles on it since I bought it (and I bought it after it had been sitting) the bike starts and runs fine it seems besides the gas leekage and the idle thing... im very worried about the hydrolic lockup, ive totally stopped riding it now, but how do I tell if im ****ed or not??

[newcomer]

Borrow a compression gauge and get a reading of your cylinder compression. Compare to your specs and decide if you want to do an overhaul. Google for compression gauge, it's another huge topic.

[kawasakininjazx6]

Ok thanks for advice