Kawasaki Motorcycle Forums banner
1 - 20 of 22 Posts

·
Registered
Joined
·
14 Posts
Discussion Starter · #1 ·
I recently got my 1981 kawasaki kz550 running and it sounds fine but when you put it in first the bike is sluggish to start and also when you shift into 2nd gear it struggles a little bit and slowly picks up speed. Also its only running on 3 cylinders the left side one is not doing anything. and when you touch the muffler that comes out of it its cold all the other is hot. I dont know what to do please help.
 

·
Registered
Joined
·
2,344 Posts
Not too familiar with the bike, but does it have a carb for each cylinder?.....If so, I would pull the plug for the offending cylinder and check it. If it is wet, you mosy likely have an ignition/plug problem...............if it is dry, you probably have a fuel problem. If one carb feeds two cylinders, I would look at the ignition/plug.
 

·
itching to ride
Joined
·
2,238 Posts
First thing do a compression check across the board. That will give you a baseline of engine condition. If the cylinder in question has good compression then check to see that the plug is firing. When you have done these two things post results and we can go further.
 

·
itching to ride
Joined
·
2,238 Posts
Check to see that you have fuel in the carb to the cylinder that is cold. Just loosen the drain screw at the bottom of the float bowl and if no gas comes out you have to find out why. You are probably going to have to pull the carbs anyway if you have good compression and have a hot blue spark at the plug.
 

·
Registered
Joined
·
276 Posts
All the above are great suggestions. It always amazes me how much drag 1 dead cylinder produces.

Am I right that this un-lit cylinder chimes in past second gear. These are pretty lean bikes for Joan Claybrook emissions, and when cold will have a lean misfire until some heat offers better fuel vaporization.
 

·
Registered
Joined
·
14 Posts
Discussion Starter · #10 ·
Ok today i drained the the carb that goes with the cylinder and it had plenty of gas. I was wondering if it could be a coil problem? Can you switch the spark plug wires around so that #1 goes to #4 and #4 goes to #1 and then #2 goes to #3 and #3 to #2. To test to see if the coil is not good? Its the first cylinder that's not doing anything so by switching the wires around to see that if the #4 cylinder starts to do nothing then its a coil problem. Can this be done?
 

·
Registered
Joined
·
276 Posts
Mike: I wondered who out there would be of my vintage to actually know Joan Claybrook. I always found it mystifying why the USA does excellent deeds like set and support the international standards for freedoms, yet wouldn't allow its own motorist see speedometer numbers greater than 85 mph. I do love irony.
 

·
Registered
Joined
·
11,328 Posts
Ignition coils on bikes usually(on the older 4's) have two ports wired together. Now once in a while coils fail internally, causing one of the sparkplugs to foul or not get a good spark.

Sparkplug caps contain a resistor to restrict the RFI so radio's don't pick up the snap and crackle of igniton when the plugs fire. This resistor can fail too or become intermittent, so I'd replace all four caps: Z1 Enterprises, Inc. - Product Catalog
 

·
Navy Vet Search & Rescue
Joined
·
8,843 Posts
Can you switch the spark plug wires around so that #1 goes to #4 and #4 goes to #1 and then #2 goes to #3 and #3 to #2. To test to see if the coil is not good? Its the first cylinder that's not doing anything so by switching the wires around to see that if the #4 cylinder starts to do nothing then its a coil problem. Can this be done?
Yes. Both wires on a coil will fire at the same time so it doesn't matter which connection on the coil runs to 1 or 4.
 

·
itching to ride
Joined
·
2,238 Posts
Ok today i drained the the carb that goes with the cylinder and it had plenty of gas. I was wondering if it could be a coil problem? Can you switch the spark plug wires around so that #1 goes to #4 and #4 goes to #1 and then #2 goes to #3 and #3 to #2. To test to see if the coil is not good? Its the first cylinder that's not doing anything so by switching the wires around to see that if the #4 cylinder starts to do nothing then its a coil problem. Can this be done?
the compression on all of them was around 125 and the sparks were all looking good.
So if spark is good why are you thinking it might be the coil? You say you have the same compression for all cylinders and a good spark so that only leaves the carburetor. Have you pulled them to peek inside?
 

·
itching to ride
Joined
·
2,238 Posts
But you have a steady blue spark at low speeds? I am confused here. You seem to be giving mixed signals. Are you saying the spark is intermittent? If so check your plug wire and spark plug cap. If it always has a good spark and decent compression then it is in the fuel system.
 

·
Navy Vet Search & Rescue
Joined
·
8,843 Posts
If that cyl fires better with the choke on, that would suggest it's too lean to fire at idle/low rpm. Two things come to mind for that. First would be a blocked pilot passageway but you say you've cleaned the carbs good. Second would be an air leak. Either a vacuum line off/uncapped or the holder/manifold leaking. Have you tested it for air leaks?
 
1 - 20 of 22 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top