Author Topic: spark on 1 and 4 NOT 2 and 3  (Read 3007 times)

Offline mister_anger

  • Motobrick Curious
  • Posts: 22
spark on 1 and 4 NOT 2 and 3
« on: September 05, 2018, 12:34:41 PM »
hello,

I am trying to start my K100 after my rebuild project.
I am getting spark on # 1 and 4 but not on 2 and 3.
Ignition coils are brand new and measured the resistance, it is fine.
HT leads are new and OK.
Replaced the ICU with a brand new one, situation stays the same.
When I switch the signal wires on the coils then the situation changes. Spark on 2 and 3 NOT 1 and 4.
Measured all the wires between the ICU and the coils, they are all fine.
Getting a nice 12Volt on both coils.
Swapped the HT leads, no result.
I am lost on what this could be.
It can't be the hall sensors because then I would have no spark at all.
So I am wondering where the split between signal to coil 1/4 and  2/3 is.

Hope someone can help me out.

thx,M
  • Belgium
  • Triumph speed triple, honda cbx750f, BMW K100RS

Offline mister_anger

  • Motobrick Curious
  • Posts: 22
Re: spark on 1 and 4 NOT 2 and 3
« Reply #1 on: September 05, 2018, 12:42:06 PM »
does anyone know if the hall sensors give a signal to both coils? Or does 1 hall sensor go to coil 1/4 and the other one to 2/3?
  • Belgium
  • Triumph speed triple, honda cbx750f, BMW K100RS

Offline mister_anger

  • Motobrick Curious
  • Posts: 22
Re: spark on 1 and 4 NOT 2 and 3
« Reply #2 on: September 05, 2018, 02:25:26 PM »
it turns out the answer is yes. tested the hall sensors and one of them is broken. Problem solved.
  • Belgium
  • Triumph speed triple, honda cbx750f, BMW K100RS

Offline Chaos

  • Administrator
  • ^ Quintessential Motobricker
  • Posts: 3157
  • Mars needs women!
Re: spark on 1 and 4 NOT 2 and 3
« Reply #3 on: September 05, 2018, 03:38:09 PM »
Glad we were able to help!  :hehehe
  • sw ohio
1987 K75S    VIN 0231
Original owner, Original litter
200,000 miles (plus or minus) and 5 paint jobs
sold 6/23
2023 Ural 2WD sidecar (BMW's bastard step child)

Offline The Mighty Gryphon

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  • Posts: 6843
Re: spark on 1 and 4 NOT 2 and 3
« Reply #4 on: September 05, 2018, 05:39:23 PM »
Wow, seems that it's been a while since we had a Hall Sensor failure here. 
  • In my garage in Marilla, NY
  • '91K100RS White/Blue
Current:
'91 K100RS16V "Moby Brick Too"

Past:
'94 K75RT "Ilsa, She Wolf of the SS"
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

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