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KZ 550 4cyl problem


Strictly Street

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A can of Seafoam, a set of plug wires and lube for a sticky mechanical advance was the fix(s)

Runs really good now! ;)

Thanks for the troubleshooting help and tips on what to do.

===== Original Post ============

1980 Kawasaki LTD 550 C1 USA model.

Kerker 4-1 headers, K&N air filters.

Dynojet kit 2305.001 installed.

(Like this when I bought it, can't verify without tearing it down)

Ignition coil mod so spark is not a problem.

I found a sticky mechanical timing advance, a little grease and it runs much better but still about 4500 rpm it breaks up till about 5500 rpm. After that it seems ok up to redline.

Any thoughts as to why it would have this narrow range of stuttering?

Edited by Strictly Street
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Your carbs have a slow, med and high range jets.

To get them really clean you need to pull them and clean them.

They aren't that hard to clean if you do one at a time so you don't get the parts confused and get everything put back where it is supposed to be.

Also don't split the carbs unless you have to.

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big +1 to everything v65 rider said.

a shop will charge you maybe $100 to $texas depending on where you take it. a dealer may not even want to touch it, as the bike is older than most of their techs probably are. :D im sure you could find a few shops that would do it though.

although i would also recommend doing it yourself. half the fun of owning a bike is working on it IMO. i know how you can feel intimidated by it. when you get down to it though its pretty much just screws and remembering how everything goes back together. once you do it, you will feel great though :)

there are lots of people here who can help you too :)

Edited by John
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Your carbs have a slow, med and high range jets.

To get them really clean you need to pull them and clean them.

They aren't that hard to clean if you do one at a time so you don't get the parts confused and get everything put back where it is supposed to be.

Also don't split the carbs unless you have to.

It seems like the transition from low to medium is the problem. Clogged or dirty jets or fuel lines does make a lot of sense. The symptom does seem to fit. And I already fixed the other troubles, whats left is the carbs.

I do have a manual for the bike, and a couple of old wrenches, hmm...

It looks like I'll have to do some reading.

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big +1 to everything v65 rider said.

a shop will charge you maybe $100 to $texas depending on where you take it. a dealer may not even want to touch it, as the bike is older than most of their techs probably are. :D im sure you could find a few shops that would do it though.

although i would also recommend doing it yourself. half the fun of owning a bike is working on it IMO. i know how you can feel intimidated by it. when you get down to it though its pretty much just screws and remembering how everything goes back together. once you do it, you will feel great though :)

there are lots of people here who can help you too :)

People who can help definitely makes me feel better!

A call to a shop or two taught me most of them won't touch anything older than a 2000. I can believe that the bike is older than most of the mechanics.

An Example:

"What year did you say"?

"1980".

"1980?!? Oh no, we don't work on bikes that old".

The guy sounded like he thought I was nuts to even have something that old. :D

The weather looks so good this week that I think I'll ride to work all week.

I'll try some 93 octane and a little seafoam. If that doesn't do it I'll try to clean them myself next weekend while its raining.

Edited by Strictly Street
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I had a similar problem on my 1978 Suzuki, a ran the fuel almost to the reserve and dumped an entire bottle of Sea Foam into it, smoked like hell, for a bit, but after I ran that for about 5 minutes, (have to play with the throttle to keep it running and get the other jets kicked in) topped off the tank and it runs a whole lot better now! $10 for a bottle. Have a fuel can handy, you won't want to ride it til you top it back off!

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Changed the spark plug wires which fixed a lot of weird troubles including the drop out at 4500 rpm.

The interesting thing was how much it cost, $12.00

I got coil wires from NAPA at $3 a piece which with a little work fit just fine.

The only other thing I found was a $50 set on ebay. Of course for the $50 they came in pretty colors.

Edited by Strictly Street
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Changed the spark plug wires which fixed a lot of weird troubles including the drop out at 4500 rpm.

The interesting thing was how much it cost, $12.00

I got coil wires from NAPA at $3 a piece which with a little work fit just fine.

The only other thing I found was a $50 set on ebay. Of course for the $50 they came in colors.

So how's the bike running now over-all?

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Haha. Sounds good man. What's the top speed on that...about 80?

80-90 I think is about it with the sprockets that are on it.

A former owner changed both the front and the back.

From what to what the receipt doesn't say.

Anyway that's plenty fast enough to get me in trouble! :D

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Ah the bikes of yesteryear...

I don't think they really were more fun, we just remember them that way.

Of course I'm now mortal instead of immortal like I was back then... sigh

I was 12 when i got my 550LTD, i rode the thing every day i could in the summer

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