TOPIC:

Ok so came back from my ride, started just fine, after 8 or so miles it started misfiring, had to race home on what sounded like 3 cylinders (exhaust 4 wasn't very hot to the touch). I think im way to rich, my spark plugs are already fouled by dry carbon after only 10 miles or so...
I'm going to put back the original mains and pilots in my carbs and see how it runs.

Couturier wrote: Ok so came back from my ride, started just fine, after 8 or so miles it started misfiring, had to race home on what sounded like 3 cylinders (exhaust 4 wasn't very hot to the touch). I think im way to rich, my spark plugs are already fouled by dry carbon after only 10 miles or so...
I'm going to put back the original mains and pilots in my carbs and see how it runs.

Are all four plugs the same?
If it's one cylinder that is failing, wouldn't it be better to find out what is wrong with that cylinder, or are you saying they will all fail, but #4 fails first?

What needles do you have? Have you read the page on fake 4D93 needles? The no-name kits, using the keyster number, have un-usable needles.

If they are the fake kits, follow the links to the carb page and the page on "three needle types". you should put the stock needle back in before going after the jets. The fake needles are way too rich even at the leanest setting.

The plugs were so fouled the spark was too weak. I have the original notched needles, (they came stock with the canadian version of the bike)
I set those at notch #3 and put the original main jet (#92) and pilot jet back. She runs better though she tends to stall when I stop at red lights with the clutch pulled in. Am I still too rich? The plugs tend to get a little sooty around them but tip has a brownish color. I'll try to put a picture on here.

J

Couturier wrote: The plugs were so fouled the spark was too weak. I have the original notched needles, (they came stock with the canadian version of the bike)
I set those at notch #3 and put the original main jet (#92) and pilot jet back. She runs better though she tends to stall when I stop at red lights with the clutch pulled in. Am I still too rich? The plugs tend to get a little sooty around them but tip has a brownish color. I'll try to put a picture on here.

J

Yes, post some photos if you can.

The metal part of the plug does tend to look more like a black ring, while the center electrode insulator should be more tan to dark tan (or light gray to gray, in some parts of the U.S., or depending on fuel blends).

I can't seem to find details on the custom intake, and the exhaust. (Sorry if I missed them in this thread.) Can you describe them?

Depending on the intake and exhaust, with stock jets, the third clip may still be a little too rich in the cruising and normal driving range of throttle positions. That would explain the slightly rich plugs, if that's how they are.

As far as the stalling goes, that can be many things. How confident are you that the valves are adjusted and timed correctly?
(Stalling when hot can be a symptom of the valve clearance needing adjustment.)

It can also be an ignition coil or pickup coil affected by heat, or, of course it can also be the replacement igniter is affected by heat.

It can also be a fuel flow issue. Make sure the gas tank vent (in the cap) is working. Make sure you are not using a see-through paper fuel filter for cars.

Have you done a compression test?

Can you post a clear sounding video of the bike?

If it helps at all i had a stuck float on #4 and did a similar thing but also making sure every wire is to the correct spot and coil 1 goes to cyl 2 and 3 coil 2 goes to 1 and 4 its the little things sometimes

Here is a link to the startup and a little revving. It also shows my setup.

Here are the plugs. Mind you, I still haven't done the fine adjustments. Some do look good, others a little too lean?

I'm just putting some notes here to recap for myself. (There are several Kz550 threads going right now.) Let me know if any of this is wrong.

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No compression test numbers yet.
All valve clearances were checked and re-shimmed.
Factory Ignition with Dyna 2.2 ohm coils.
Short free-flowing exhaust.
Custom, short, four-gang filter box. (Looks to be a pleated paper element.) Nice fiber work.
K&L needles set to 3rd clip.
Stock main.
Stock pilot.
Air screw setting?
Fuel level set on all four? Did #4 stop leaking?
Plugs look rich, but about the same across all four. #4 may be lighter on the insulator, but lighting was varied.
(I try to photo all four next to each other at the same time so the lighting is not a variable.)

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The video does not sound that bad, actually. Is it misfiring there, or is that with it running normal?
Did you do a water test to check for misfire, or is the pipe (#4) so cold you can just grab it?

I think the rich plugs are from being on the 3rd clip position (counted from top), as I've found that to be a little much. But 2nd clip position would be too lean. There is a shimming needle page on my site. I would try a .6mm to .8mm shim. But that is not the dropping-out cylinder problem.

Is it for sure only one cylinder dropping out when hot?
If so, my first reaction would be to check the valve clearance on that cylinder. But you've done that.
I still think a compression test would be a good idea just in case there is something strange on that cylinder, but the odds are lower if it is running ok before the cylinder drops out.

So next is ignition. If two cylinders were dropping, in pairs 1-4 or 2-3, I would suggest swapping coils around to decide if it's a coil or the Dyna S. The Dyna S can be sensitive to voltage, so I would try to measure the voltage on the battery and the positive voltage going to the Dyna S itself while running and misfiring. The Dyna S grounds through the motor, so does the starter, so the ground should be ok.

How long do you ride before the cylinder(s) cut out? Does it always cut out at that distance or time now? Or is it for sure, more random?

I've been riding the bike almost daily now for a week I would say. I recleaned all the carbs and it looks like it did the trick. No misfire, no dropping of a cylinder, all cylinders are too hot to touch. Most definitely still needs a fine tuning on the carbs, like you said I'll try the half increments on the clips, I'll recheck the fuel level, synchronize everything then it should be close to perfect! One of the carb leaks from time to time but it's manageable, like I said it still needs a little tuning.

Thanks for the help, your website is amazing by the way!

And you are correct for most of the recap, except the pick ups are the original electronic ones. I'd have to check the air screws but I'm fairly sure they are stock as well so 1 1/8 turn (if i remember correctly). The air filter is a K&N from a fiat i think that I adapted. Thanks for the kind words on the fiber job. It was my frist try and I'll say it was not easy haha.

I haven't had any major problems for a good 200km.

Thanks! And yes, I had your ignition mixed up with another 550 thread. I edited the recap to Factory ignition with 2.2 ohm Dyna coils.

Well, at least it seems to be running a little better now. Keep us informed.