Topic: No Voltage ?..

[Tommysbike]

74' CB750 four, old school chopper saved from the shed...  has voltage to the 1 & 4 points but no voltage to the 2 & 3 ??... I guess that would be the windings on the L side of the bike??.... Any help for a rooky?... Thanks for any help or advice...

[Tommysbike]

It ran for a short time??... I really need a manual. Has anyone seen this problem before?... Another problem is it has what looks like an old "santee" harness and electrical box on it... One set of breakers has voltage but nothing on the other set?...

[OldSchool_IsCool]

Here is an interactive wiring diagram:

http://oldmanhonda.com/MC/wiring750K1.html

If you have a lot of electrical mods, it's probably no good to you, but it may help.  On the diagram, turn off all systems but the coil and it might give you some insite into how the coils/points/condensord get power.  Basically power flows from battary, thru the stop switch, splits to each coil which then has it's own "primary" wire that runs to the points, then thru the condensor and finally to ground.

Do the dead point open?  What if you shorted out the condenser on that side, do you get a voltage reading across the open points then?  Since one set of points shows a voltage, you have good wireing through it's coil back to the battery.  There must be a wire break somewhere between the "split", the "dead"coil, between the coil and the "dead" points or between the points and ground (thru the condensor).

[Tommysbike]

Thanks, I'll try the short... The dead set is opening and I swapped the condensor from another engine out of desperation. I will fool w/it a bit more tomorrow. I am willing to bet it is a wiring issue. I just don't have a clear understanding of how it works. Thanks for the link, it all makes perfect sense and I hope to get this bike squared away soon....

[Tommysbike]

Well, I messed w/the bike a bit more today. I just can't get the #3 & 4,... yellow lead coil and breaker set to respond to voltage??... I can jump the blue side w/alligator clips and a wire  from the hot side of the soliniod to the blue lead coming out of the coil, no problem, those cylinders fire...  switch the clip to the yellow lead on the other coil and nothin', no sparky, sparky... It does the same thing with two different sets of coils?.. Also, I tried jumping the voltage from the "hot" side of the breakers over to the other set and still, nothin"..... Well, Obviously there is somthing I don't understand about the system?... Thanks again for your help and advice!...

[mic-57]

Here is a diagram that makes it very simple http://www.hondachopper.com/images/simple.wiring.diagram2.jpg.
your coils share a common power supply, you should be able to follow the power through the circuit. first at the wire that feeds the coil, next at the wire to the points, then at the points.

[OldSchool_IsCool]

Did you say cylinders 3&4?  Those cylinders don't share a coil.  Sould be 1&4 on BLUE and 2&3 on yellow.

But crossing plug wires that wouldn't explain no voltage across an open point set.