hey there,

I bought a project bike k100 from 1984, the engine on it wasnt working well anymore and it came with an extra engine from 1998. 

Im currently trying to swap all the wiring to match the ones with the frame and its been going good. 
ive stumped onto the ignition wires, the new engine has 3 coming out of it, and the old engine had 3 wires as well, but one was cut and not used. 

New engine
https://ibb.co/fqWC0gC

Old engine
https://ibb.co/DCb07WX

and the not used cable from the old engine
https://ibb.co/28zVHcV

So is the cut cable the same as the one with the blue connector in the new engine? (this one https://ibb.co/cCkMCN8 https://ibb.co/LN4RpJz )
i do not have an attachement to it for my frame wires.. so what does this cable do? its a big question for me. 
I hope you can help me!

tristan285 wrote: I bought a project bike k100 from 1984, . . . it came with an extra engine from 1998. . . .

In 1998 there were no K100 models. The 2V model production had ended around 1989 and the 4V K100 production had ended around 1992.

Have you made a typographical error?

ah i did not know that!
i bought the project from someone who had no information at all about it, so its all guessing for me. 

i thought it came out of 1998 because of the label on this cable: https://ibb.co/cCkMCN8 
i do not know the production year of the engine now..

Laitch wrote:

tristan285 wrote: I bought a project bike k100 from 1984, . . . it came with an extra engine from 1998. . . .

In 1998 there were no K100 models. The 2V model production had ended around 1989 and the 4V K100 production had ended around 1992.

Have you made a typographical error?

K100LTs were produced until October 1991.

The manufacturing date of the block is cast into the engine block.

i will check the right production date tommorow! 
sorry for this mistake! 

but it shouldnt matter that much for the function of the wires right? 
so strange that i dont have a connections for the blue wire in my frame wires..

Your old bike had a Jetronic ECU.  Is it possible that the new engine is a newer 4 valve or K1100 engine that may need a Motronic ECU and harness?

Looking at your other post, your 'new' engine is an 8v too, so compatibility shouldn't be an issue.

The 'three' wires on your new engine will be:

1 The Hall sensor (black plug)
2 The oil pressure switch (single brown/green? wire, white plug)
3 And - possibly - a connector for a temperature gauge (blue plug)

You don't need 3

The chopped off wire on your old engine might have been for the same thing, but your bike doesn't have a temperature gauge?

Only a suggestion, becasue I've never had a K with a temp gauge, but I do think the sender is down in the oil/water pump somewhere?

Edit: BTW the picture of your old engine seems to show that only the Hall sensor wire was complete - although you can see the oil pressure switch connector & wire, the other end of it can't be seen where it should be under the T-shaped cover running down towards the oil pump.

chris846 wrote:I've never had a K with a temp gauge, but I do think the sender is down in the oil/water pump somewhere?

The temp sensor for the gauge replaces the drain plug at the bottom of the water pump.

chris846 wrote:Looking at your other post, your 'new' engine is an 8v too, so compatibility shouldn't be an issue.

The 'three' wires on your new engine will be:

1 The Hall sensor (black plug)
2 The oil pressure switch (single brown/green? wire, white plug)
3 And - possibly - a connector for a temperature gauge (blue plug)

You don't need 3

The chopped off wire on your old engine might have been for the same thing, but your bike doesn't have a temperature gauge?

Only a suggestion, becasue I've never had a K with a temp gauge, but I do think the sender is down in the oil/water pump somewhere?

Edit: BTW the picture of your old engine seems to show that only the Hall sensor wire was complete - although you can see the oil pressure switch connector & wire, the other end of it can't be seen where it should be under the T-shaped cover running down towards the oil pump.

thanks for clarifying! so there will be no problems with the compability! thats good. 
i dont think my bike will have a temperature gauge, so the wire will not be used i think. 

again, thanks for clarifying!

Hey I'm only guessing!
But Duck's post is a big help.

Maybe check all three of the wires on your old engine - and see where they do - or don't - go to.
But the bike definitely only needs the Hall sensor wire (black plug) to run.

yeah indeed, thanks duck! ill check it out. 
ill post an update when i work on the k100 again!!