Coils don't match???

Cuff wrote: Hey there and thanks to all who helped out. Got new coils in the bike now and she's never ran better. This issue has also put a fire under my ass to take care of those little things like checking wires, hoses and connections. Of note the bad coil was intermittent after all and was testing fine ( and running fine) but needed to be retired for reliability. Again, thanks.

As I sometimes say, the thing generically referred to as a "coil" is actually a high voltage flyback transformer and they can never be tested with a DVM. You have to be able to crank up about 50kV on a HIPOT tester and check for leakage between windings. And, even then, you can't be sure the coil is good because most flaky coils work OK cold and then start misfiring when they get hot.

bountyhunter wrote: As I sometimes say, the thing generically referred to as a "coil" is actually a high voltage flyback transformer and they can never be tested with a DVM.

or at least never confirmed good with just a DVM... but if the primary (or secondary, for that matter) shows open or shorted to zero, then it can probably be tossed without further testing.

DVM is like the DMV. Passing the test doesn't mean you're a good driver, but failing it means you're a bad driver.

So as luck would have it just when you get one thing working like a charm another goes. I now have a fueling issue. The petcock is getting fuel to my Fram clear filter but won't fill it while set to prime. The bike will run but not very well.

I have a shut off valve that when disconnected from the filter that will allow me to drain the tank in no time. Just when it's hooked up to the filter it won't prime the carbs like it did before.

The filter is new and clear free of obstruction.

:woohoo:

If that filter is for a system with a pump, it probably won't want to flow well under gravity flow. Get a good filter for a gravity system, Z1 has them as well as most any Bike shop or small engine equipment shop.

Cuff wrote: So as luck would have it just when you get one thing working like a charm another goes. I now have a fueling issue. The petcock is getting fuel to my Fram clear filter but won't fill it while set to prime. The bike will run but not very well.

I have a shut off valve that when disconnected from the filter that will allow me to drain the tank in no time. Just when it's hooked up to the filter it won't prime the carbs like it did before.

The filter is new and clear free of obstruction.

:woohoo:

Yes. I can confirm your findings if it's a paper filter with clear case. I made a video showing the problem.

www.youtube.com/profile?user=loudhvx#p/u/5/IBchiO4yEDw

This only became problematic several years ago. I used to use those same filters for 15 years. I think something in the newer gasoline is dissolving the glue in the filter and making it clog the paper after just a few days or weeks.

You need to use a metal screen filter, or scintered brass filter (for gravity systems, like MotorHead said), or you need to carry a short, fat hose to blow into the gas tank every so often :laugh:

Thanks for the video. My filter was larger and along with some cloging I'm sure there was too much air space that created splashing effect. I picked up a smaller screen type filter that works well now with a longer hose that routes the fuel line in a more gradual bend.

However, the bike was not runing well still so I decided to pull the carbs one more time as the #1 cyclinder was not warming as much as the rest.

After I pulled the carbs I went and checked the foats and give it another cleaning. Guess what? Check valve bearing, wieght and retainer clip are gone. Don't know where but either my carbs were never going to run well when I bought the bike or I lost these parts the last time I cleaned the carb.

I more than likely missed this issue with the electrical problems overshadowing everything else. One more trip to my parts guy. My wife is starting to think I work there now.:lol:

Hi All,
I have a 1976 KZ900 with a dyna S ignition and 3 ohm coils i assume. How would i test the ohm's on the coils? Where do i connect the meter leads to?

Kaw900 wrote: Hi All,
I have a 1976 KZ900 with a dyna S ignition and 3 ohm coils i assume. How would i test the ohm's on the coils? Where do i connect the meter leads to?

Each ignition coil has two spark plug wires,
and also has two small wires connected to it.

The small wires are from each end of the coil's primary winding.

The measurement desired is the resistance (ohms) through the primary winding.

Stock coils have permanently attached small wire "leads" exiting from the coil.
One small wire is colored red/yellow,
The other small wire is black or green (depending on which of the two coils).
With this type coil, connect the ohmmeter to measure resistance between ends of the red/yellow wire and black wire (or green wire).

A coil design such as a Dyna green coil, doesn't have permanently attached small wire "leads" exiting from the coil.
But instead has two terminals with screws.
The red/yellow wire attaches to one of the screws.
The black (or green) wire attaches to the other terminal screw.
With this type coil, connect the ohmmeter to measure resistance between the two screw terminals.

Good Fortune!

Stock coil

Thanks Patton,
Going to check them tomorrow.

You know, I think in my old age I'm going slightly stupis. Not only was my check valve missing but in cleaning up my carbs the first time I plugged the vent ports as well. No wonder the bike didn't run well.