1980 750H bare bones for mattylight

Diagram

That looks good to me. I assume the battery + in the diagram is not permanently connected, correct? If so, the coils will be on all the time. You should make sure to have a way to kill the power to the coils and Dyna S.

I'm not familiar with the wire colors on the Dyna S, though. If that wiring works on the stock coils, it should work with dyna coils. There is no chance the screws on the coils are touching the fram anywhere, correct? On some bikes, the screws end up real close to the frame and sometimes can cause the coils to short against the frame.

One way to insulate screw heads from metal coil mount spacer is with nylon tie wraps secured around the metal spacer.



Good Luck!

Thanks. The power to the coils goes through the key switch. I followed your diagram for that. Thanks again, I will be getting the new coils on Monday and will let you know.

We seem to be having a problem getting the engine past 4000 rpm. It has 2 exhaust pipes with no crossover pipe. Could that be a problem? 1&2 into one pipe, 3&4 into the other. The compression is about 125 lbs in all cylinders. Could the old coils be breaking down at high rpm? Mabey the new Dyna coils will solve it. Power to the coils is just under 12 volts. Thanks again.

snerff wrote:

We seem to be having a problem getting the engine past 4000 rpm. It has 2 exhaust pipes with no crossover pipe. Could that be a problem? 1&2 into one pipe, 3&4 into the other. The compression is about 125 lbs in all cylinders. Could the old coils be breaking down at high rpm? Mabey the new Dyna coils will solve it. Power to the coils is just under 12 volts. Thanks again.

no crossover pipe. Could that be a problem? -- Not a prime suspect imo.

If not already done, would double-check ignition timing, and watch advancer under timing light move quickly back and forth as rpm is varied by blipping throttle, to assure the advancer isn't stuck in closed position.

Is it "breaking up" at 4000 rpm, or just petering out?

Power to the coils is just under 12 volts.--Maybe old hard worn sparkplug wires are leaking voltage and causing weak spark at higher rpm.

What are sparkplug readings?

Possible fuel starvation issue?

Just pondering.

Good Luck!

Well, is 125 psi good compression for a 1000? My 550's are all above 180 psi. My friend's worn out 650 had around 150 psi after about 100,000 miles.

If you're sure the engine is ok, then the next step would be ignition, so I might wait for the dyna coils.

KZ1000 standard compression is 128~156 psi
Service limit is 100 psi, with 14 psi variance between cylinders.

Some 1000's reportedly perform okay on less than 100 psi.

In the case at hand, if not already done, would verify correct valve clearances, even if compression test figures are okay.

Too tight valves can cause loss of compression at normal operation temperatures, even though the valves are seating when compression testing a cold engine.

Good Luck!

Thanks, guys.I will wait for the new coils and go from there. It seems to be petering out, I will check the vent cap also.

Well, I got the coils back from Dyna. When I hooked them up the engine broke down at about 4000 rpm like before. The idle had to be full open and the choke on half just to keep it running. Again old coils worked fine, within reason.
When I was about to junk them out of frustration, I called Z1. I explained everything to them and it was a mystery at first. Z1 suggested I unmount the coils from the frame mounting studs, a long shot at best. It should not matter, as the mounting lugs are not grounded. As soon as I did that it ran like a top.
I have now mounted the coils to a piece of Delrin to isolate them from the frame and everything is finally ok except for the mystery of it all.
Again, the factory coils were mounted to the frame and they worked. I can,t figure out why the Dyna's were different. Even Dyna cannot figure it out. I know it was not my wiring, went through it at least 8 times and checked every wire.
So there you are, if you guys can explain that I will be really impressed. Thanks again. Oh again, thanks Patton and loudhvx for your time.

THe wiring studs on the dyna coils stick out. Is there any chance they were touching the frame or even close? Close is all it takes for vibration to make then short out. I have seen that on several bikes.

Have to say, glad Z1 thought of that. Did you talk to Jeff at Z1? I wouldn't be surprised if he figured it out.

Still, that is a mystery, as the center mounting core of the coils should not be electrically connected to the coils' wires. I know on bikes, they work bolted to the frame. Very strange.

Well guys, just when I thought I had it made. After I remounted the coils it ran great and reved to 9000 instantly. I started it this morning and it bogged down at 4000 rpm. At full throttle it shut down unless I backed off the throttle. Plugs now run clean. Just can,t get it past 4000.
I learned one thing. Never build a vehicle around an untested engine. Seems like a fuel problem. Changed the filter and even ran it stright to the carbs, no change.
I know it is difficult doing this by mail. I wish we had a good motorcycle mechanic around here I could afford.
Anyway thanks for all your help in the past. Anyone want to buy a good vehicle minus motor? Just kidding I guess but I,m burned out about now.