Topic: Cb750 cylinders 1 and 3 aren't firing?

[Jaxbchcb]

My cb750 sohc cylinders 1 & 3 aren't firing for some reason but when I switch the coils the problem moves with the coils!? I know the coils are good because I chec with multimeter, the points are good and timing is perfect, and the spark plugs are new so I have no idea what's go on! Any help please?

[70CB750]

Odd.  The cylinders are paired 1-4 and 2-3.

You say the problem moves with coils, how does it move?

[goldarrow]

Stock coils rarely go bad.  Check make sure wires are good, also one coil goes to 1 and 4, the other coil goes to 2 and 3.   Condensers often need replace.

[Jaxbchcb]

Odd.  The cylinders are paired 1-4 and 2-3.

You say the problem moves with coils, how does it move?

If I put #2 coil on #3 it works etc.

[Jaxbchcb]

Stock coils rarely go bad.  Check make sure wires are good, also one coil goes to 1 and 4, the other coil goes to 2 and 3.   Condensers often need replace.

Yeah it's weird I checked the coils and those are good. How would I test the wires with a multimeter?

[70CB750]

Sorry, can't see the inside of your head from here.

coil 1 connected to 1-4
coil 2 connected to 2-3

Which one is not firing?

Now you move the coil 1 to feed cylinders 2-3 and coil 2 to feed 1-4.

which one is not firing now?

[madmtnmotors]

1/3 are not a pair. The leads from one coil should be going to 1/4 and the leads from the other coil going to 2/3 (so make sure that is there first!).

[Jaxbchcb]

Thanks for the replys! I found a wiring diagram and found out what yall were talking about that 1 and 4 are on one coil and 2 and 3 are on another. I guess the guy who had the bike before me put the coil wires on 1234 haha so no wonder it was acting all crazy!! But I corrected it and everything is good now