Kz running like crap, can`t figure it out???

I bought a 77 kz 1000, it ran perfect when I got it a month ago. Then it started to run badly, missing in the low to mid range and no power. Checked the plugs they were fouled with carbon deposits. Means running rich right? so I cleaned the carbs and put in new plugs. Ran great for a day or two then started to run crappy again and the plugs fouled with carbon. The guy that sold it to me said his bike mechanic recomended a new electronic igition. So I was thinking that the points and condensers might be bad. Has anyone had simular problems that a electronic igition has solved. Plus has anyone had good results with Dyna S or should I put in new points and condensers? Thanks for any input!!

Would at least check the points and timing before buying $200+ worth of stuff to fix a problem you MIGHT have, how's the coils test out? Are they getting proper voltage?

Check the point gap and static timing also

Could also be weak coils or bad secondary wires or bad caps. A careful check of the electrics seems in order.

Wrong spark plugs?

Defend132 wrote: I bought a 77 kz 1000, it ran perfect when I got it a month ago. Then it started to run badly, missing in the low to mid range and no power. Checked the plugs they were fouled with carbon deposits. Means running rich right? so I cleaned the carbs and put in new plugs. Ran great for a day or two then started to run crappy again and the plugs fouled with carbon. The guy that sold it to me said his bike mechanic recomended a new electronic igition. So I was thinking that the points and condensers might be bad. Has anyone had simular problems that a electronic igition has solved. Plus has anyone had good results with Dyna S or should I put in new points and condensers? Thanks for any input!!

Fouled plugs as you describe are generally caused by the carburetors running rich. The carburetors may be very clean but still running rich. Was the air box recently switched out for filter pods? Were the exhaust pipes recently changed to more open pipes? Is the pilot jet properly set? Is the choke working properly. All of this can cause rich running.

If you are running with pod filters most on this site will tell you to change back to the airbox. I switched to pods from the airbox and reduced both the main and idle jets by 15% as recommended by K&N and have never had a problem. Your jets should have a size mark on them and you can look up the proper jet size on any site like this one ( www.ddsmotorsports.com/oempartfinder.htm ). Just look up your bike, then the carb for your bike, and then the jets.

My guess is that changes were made to the breathing aspects of your bike and that caused the plugs to foul. Who ever made the change couldn't figure it out so put in new plugs and sold it.

Thanks for the input guys. It does have the right size spark plugs (double checked). And it does have Pod air filters on. It also has a 4 into 1 exhaust that has an open pipe (looks like it has been on the bike for a long time). Seems like the choke does not help with starting. I will check out the jet size on the site. So I should have jet sizes that are smaller?

So I should find out the original jet sizes and reduce them by 15 %?

Worn out piston skirts and in need of a valve job, with guides, seals and springs.
Sorry! That's how these old engines are!

Did you do a leak down test??? Better than a compression test.

Nothing a $1000 dollars can't fix.

That's why the old ones are cheap.

Defend132 wrote: So I should find out the original jet sizes and reduce them by 15 %?

Sorry for the late reply, I have been rather busy lately.

If the bike had just been changed from an air box to pods, then yes I would recommend reducing the jet sizes by 15%. The exhaust change will make a difference as well however. The easier the engine breathes, the richer the fuel air mixture becomes. That is true for both in air filter intake and the now more open exhaust.

Lots of forum participants will tell you go back to the air box, but you may have to mess with the jets simply due to the exhaust changes. If you go back to the air box expect lots of frustration with getting the rubber boots between the carbs and the air box on properly. Many however will tell you that the bike runs better. Mine seem to run good with pods and the 15% jet change.

Before giving up on spark you should perhaps check your coil resistance. The primary side (between the two spade lugs) should measure 1.8 to 2.8 ohms. The secondary (between the two spark plug wires) should measure 10.4 to 15.6k ohms with the spark plug caps taken off. I got these numbers from my kz1000 service manual The cap resistances should all be about the same. If I remember correctly that should be about 4.5k ohms. There is no value for cap resistance in my service manual. When you put the caps back on you want to screw them on snug, but don't strip them, which is each because you are just screwing them into rubber wires. If they are stripped already simply cut off about a quarter inch of wire and try again. If they get too short buy new ones.

Worn out piston skirts and in need of a valve job, with guides, seals and springs.
Sorry! That's how these old engines are!

Did you do a leak down test??? Better than a compression test.

Nothing a $1000 dollars can't fix.


Yep happened to me. I would wonder if seller knew this when he sold it to you.