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Discussion Starter · #1 ·
I have just recently bought a 2004 zr7s.

I think that it is running rich because of the poor fuel economy, starts without choke, dies when choke is applied, the spark plugs are black. I am used to getting 70 mpg (imperial gallons) - 58 miles per US gallons from my KLR 650, so getting half of that is not nice. I was told that the carbs were just cleaned just prior to my purchase but am wondering if something happened in the process of cleaning them that is causing this over rich condition.

Apart from checking the air filter which I will do and cleaning the spark plugs, I was also going to turn in the jet screws in back to 'snug' lean factory settings and then out 2 turns. Can I do this with the carbs in place from the bottom. There doesn't appear to be much room to put in a screwdriver. If I use an L shaped screwdriver, it is difficult to count the number of turns because the frame and cylinders get in the way. And what type of screw driver do I need as I cannot see the screws. I think that the sealed covers have been removed. I don't want to remove the carbs if I don't have to.

I apologize if this is not posted correctly. It is my first time on a forum.
 

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You can get a special screwdriver for adjusting the idle jet screws. Cost a bit though. I found it easier to take the carbs off to set them. Be aware that those screws only adjust the mixtures at idle and low throttle inputs.

I would re-clean the carbs. This way you can inspect the internals to be certain that nothing is wrong. Also the previous owner may have placed a couple of washers under the needle to richen up the mid range.

Also make sure you are using the correct octane fuel. For some strange reason ppl beleive that by putting in high octane fuel will increase the power output, when all it does is foul up plugs over time. (unless you have altered the tune to suit this fuel)
 

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Johnny Blue Lightnin'
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I made a screwdriver to adjust mine. I took an old metal coat hanger and cut it about 2 1/2 inches long. I laid one end on a vise and smashed it flat with a hammer. I used a file to dress it up a little so it looks like a small flathead screwdriver. At about 1/2" from the opposite end I bent it into an "L" shape. This gave me something to turn it with and something to count with.
 

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Discussion Starter · #4 ·
So jetting screw is a flat type screw head?

Does adjusting this affect jetting at highway speeds, say 5000 rpm?

And...how do you list more than one bike in your profile. I have three but it only allowed me to post one.
 

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Johnny Blue Lightnin'
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Yes. The idle mix screw is a flat head. It hasbasically no effect at anything above 1/8 throttle. Above that the engine is drawing from the main jets which are being regulated by the needles.

Reset the screws. Clean or replace the plugs. Check the air cleaner and also check for gass in the oil. The ZR should not be running rich. If it has been poorly jetted or the carbs assembled incorrectly or the diaphrams damaged it could run rich.

What i have at the bottom of my posts is my "signature" You can access that through your account page.
 

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Discussion Starter · #6 ·
Okay thanks Jon,

One more dumb question: How do you check for gas in the oil?

Also the bike came with Kawasaki hard side luggage. There is no other name besides Kawasaki on it. I don't know if Givi made it or not, but if I want to get a top box to place on the back rack, I don't know what the rack model number is. Perhaps i can contact Kawasaki.
 

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Johnny Blue Lightnin'
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The Kawasaki luggage is Givi. I dont think they make it (racks) any more.

Checking the float heights is a good idea. Hopefully no one has disturbed them because they are a pain to set. You can check the float heights on the bike.
 

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Discussion Starter · #9 ·
okay...another quick question....

I have tank off because there is no free play in my choke cable and have to access adjuster. I am hoping this is why the bike is running so rich.

Dumb question here. Is the choke on when the lever is pulled towards you? That is where the partially open butterfly valve and arrow is pointing.

When the choke is on, I assume that is when the slide is sticking out to the left. When the choke is off, should the thin brass rod be all the way touching the carburetor to the left?

And the adjuster is sort of under the frame. How is the cable supposed to be loosened to provide 2-3mm of free play?

Sorry for the silly questions.

Joe
 

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The choke is on with the lever pulled towards you. If the choke is on, even slighty then you will run richer. I can't help you with the choke adjustment as I've never had the requirement to do it.
 

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Here is a handy tip for correctly setting the pilot mixture screws.

If the throttle is lightly "blipped" at idle, and the rpm drops below the set idle speed, then rises up to the set idle speed, the low speed mixture screws are probably set too rich: try 1/2 turn in, to lean the idle mixture.

If the throttle is lightly "blipped" at idle, and the rpm "hangs up" before dropping to the set idle speed and there are no intake leaks, the mixture screws are probably too lean: try 1/2 turn out, to richen mixture. Be sure there are no intake leaks.

Also make sure that the same adjustments done for each of the 4 carbies. Remember to use the halfing method to nail this setting. For example, blip throttle rpm dips then rises to idle, too rich.........1/2 turn in. Blip throttle and rpm hangs, too lean.......1/4 turn out. Blip throttle and rpm hangs, still too lean......1/8 turn out and so on and so forth.

If you find yourself chaing your tail or without making any adjustments the idle hangs for one blip and dips for another, dismantle, clean and check the carbs especially the pilot circuit and needle. I found one set of carbs I was trying to adjust the pilot needle was missing an o-ring and was the cause for all sorts of problems.

This is screwdriver I was taking about before. It's on my to buy one day list. At the moment I use a ground down small screwdriver.

http://www.ebay.com.au/itm/170841141253?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649
 

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I made a screwdriver to adjust mine. I took an old metal coat hanger and cut it about 2 1/2 inches long. I laid one end on a vise and smashed it flat with a hammer. I used a file to dress it up a little so it looks like a small flathead screwdriver. At about 1/2" from the opposite end I bent it into an "L" shape. This gave me something to turn it with and something to count with.
I cut a stubby one right at the point it widens for a better finger grip, whole thing is like 2 inches long at most maybe shorter and works great, think I also ground the head down a bit to the size needed
 
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