TOPIC:

Hi guys, I’m new to forum, have posted in the welcome area.
I’ve restored a 1981 gpz1100b1 bike was running rough, the would be ok, then splutter etc etc. I have found the efi throttle bodies in bad shape, the fast idle cam follower worn out, etc. so I’ve decided to carby Mikuni rs34. So whilst these are coming, I need to understand the ignition tie up with the EFI ECU and what needs to be disabled or jumpered? I know this conversion has been lots of times before so I am looking for information from those who have accomplished this please. 
cheers

If you haven't already, download the KZ1100 manual from here: kzrider.com/modules/ServiceManuals/GPZ11...R_Service_Manual.pdf

On pages 9-10, 9-11, 9-12, you will see the wiring diagrams for the B1 (both the European and American models are shown)

The only "link" between the ingition system and the EFI electronics is a single 3-pin plug: (could be a 4-pin plug with 3 wires, I can't remember )
The Red wire is Ignition +12V, Black and Green wires are the ignition "pulses" from the ignitor, which are used by the EFI electronics to "synchronise" the injection pulses. "Earth", or "Ground" (0V) is the Black/Yellow wire from the ignitor module . Ensure that the ignitor is properly "Earthed" to the frame  for cooling.
If you follow the Black wire from the ignitor you will see that it is also wired to the Tacho instrument in the cluster, via a 4-pin plug, inside the head-light bucket.

​​​Simply un-plug that 3-pin plug and remove all the EFI equipment.
It's that simple.
Given correct air/fuel/compression, the engine will start and run just fine!

H.

 

Thanks very much, I shall have a look at it and follow your instructions.
cheers
jason

This is helpful as I am performing the same EFI to Carby change on an 80 G1. 

I ripped off the FI from my wife's big GPz last year. Off the top of my head, it all just unplugged and it landed in the spare parts pile... if it ever is needed again   

 

I must say to me that is a great looking machine. 
Thank you for the eye candy.

Slayer I may need to come calling 

Hi all have mounted the carbs etc, but next problem is the petcock is in the way, not wishing to weld into another position, I’m seeking alternatives petcock set up, maybe a remote one bracketed off the frame? What have other people done, that’s not invasive to a freshly painted and internally treated tank?Also need to work out what to do with the breather, maybe a catch can that drains back?

Spaghettijet wrote:

Hi all have mounted the carbs etc, but next problem is the petcock is in the way, not wishing to weld into another position, I’m seeking alternatives petcock set up, maybe a remote one bracketed off the frame? What have other people done, that’s not invasive to a freshly painted and internally treated tank?Also need to work out what to do with the breather, maybe a catch can that drains back?

If you find the time, search for a members posts (Otakar is the member) and he did a rather clever conversion of a KZ1000M or K model into a GPz-style model. He has like 5000 posts so it will be a time consumptive process.  However, he ran into the same issue you did...the petcock interfered with the carbs....and I think he was using a 1981 GPz tank (like you).  He had a simple solution to your (and his) dilemma...an inline valve, if I recall. 

Check out Howard's ELR tribute build, he has done this conversion

See here:
www.kzrider.com/forum/11-projects/617040...elr-tribute?start=48

H.

I've done the same RS conversion on my wife's bike. It's not a big deal to a competent welder. Have a look...

If you look closely above, you can see that the welder didn't take off any more paint than was needed. Put the tap where you want it and plug the pressure regulator. Easy peasey and done.