NC21 engine into NC24 help needed! **UPDATED WITH PICS**

[Homer]

Hiya,

I'm in the process of transplanting an NC21 engine into an NC24.

I've noticed an extra bit of wiring on the NC21 engine. Coming from the right hand side of the NC21 engine, at the bottom towards the rear, there is braided sheath with 5 wires that terminates in a black plug.

At the corresponding location on the NC24 engine, there is a little wire connected to a terminal on the engine. This wire seems to splice into a braided sheath with 6 wires that terminates in a green plug. This is the wiring that comes from the right hand side of the engine, towards the front (not sure what it's for... oil level switch, clutch switch or something).

Can anyone shed any light on this? I thought it would be a straight swap, and, as I'm not sure what any of this wiring does, I'm not sure how to proceed.

Any help much appreciated - I can hopefully post some pictures if that would help explain what I'm on about.

Cheers

[paul nc 24]

pop up a couple of pics homer dont panic the guy's here will soon get it sorted.

edit: if iam right its the pulse generator cable's you are talking about?

neo should have the answer he will be along soon enough. i have 4 nc24 engine's here so dont panic .

[Neosophist]

There are a few differences between the ZG and RG models of NC21 loom. The single tang your referring to is the neutral switch I think, i'm not too sure though (pictures will help)

The only difference with the model you have will be that the plug is in a different place, worst case scenario you will have to cut a couple of wires and join them together...

[Homer]

Ok, thanks.

I'll try and get pictures posted asap.

Cheers

[Homer]

OK, I've finally managed to get photographs posted!

This pic is of the goosed NC24 engine which has been removed from the bike. You can see the tang, and the wire for it which seems to splice into the braided sheath with the green plug. I reckon this is for the neutral switch:


This is a pic of the corresponding location on the replacement NC21 engine. Instead of the tang, there is what appears to be a mechanical switch, a braided sheath with 5 wires which terminates in a black plug:


On the NC24 engine, the wire from the tang (1st pic) seems to form part of the green multiplug, which has 6 terminals on it. On the NC21 engine the green multiplug only has 5 terminals and, as you can see from this pic, it does not connect to the switch shown in the previous pic:


This is the NC21 engine with the switch removed. The shaft can be clicked one position forwards and one position backwards, which is why I think it must be the neutral switch:


This is the switch:


So, if this is the neutral switch, I could use some help trying to come up with a workaround. I guess the switches are designed differently as the NC24 has only one wire and the NC21 has 5 wires. Everyone I asked reckoned the NC21 engine would be a straight swap for the goosed NC24 motor and I didnt think there would be differences in the wiring. Electrics are not my strong point!

Anyone care to offer an opinion cos I'm stumped!

Cheers!

[Neosophist]

Interesting, the plot thickens.

You are correct in saying it is the netrual switch, pictured on the NC24.

However.

Part# 35600KE8003 is listed for both NC21 and NC24 in my parts manuals. (same as the NC30/NC35 too)

Are you sure its an NC21 engine? What is the engine number of the engine your trying to put in.

You'll need to match up the wires and splice them together im afraid. Still thats not standard *confused* but intrigued

The only Engine I don't have parts book at hand for is the VFR400K (training bike) i'm looking for info now, i'll keep you posted.

[Homer]

I cant check the engine numbers at the moment, but I'm sure it's an NC21 motor. I'll have a look tomorrow and post my findings.

What I need to know is how to get round the fact that it is a totally different neutral switch and has 5 wires. I have no clue how I can make it work.... Must be some kind of workaround, but bike electrics go over my head!

[Homer]

Neo,

I've looked over both engines and cant find an engine number. Probably covered in crap, so if you know where the engine no should be, let me know and I'll look again.

Both engines look identical, aside from the neutral switch, and the replacement engine has the tell-tell 'HM 399cm3' on it, same as the original NC24 unit. I am absolutely certain it is from an NC21, although I cant explain why it has a different neutral switch.

Any ideas on how I can go about bypassing it?

[Neosophist]

Neo,

I've looked over both engines and cant find an engine number. Probably covered in crap, so if you know where the engine no should be, let me know and I'll look again.

Both engines look identical, aside from the neutral switch, and the replacement engine has the tell-tell 'HM 399cm3' on it, same as the original NC24 unit. I am absolutely certain it is from an NC21, although I cant explain why it has a different neutral switch.

Any ideas on how I can go about bypassing it?

Engine numbers on the top on the right hand side.

As i wrote before, You'll need to match up the wires and splice them together im afraid.

http://www.jacksons-lair.co.uk/VFR400RH ... Manual.zip" onclick="window.open(this.href);return false;

The NC24 owners handbook is there, it has the NC24 wiring diagram, you can use it to find out where the wires go, you'll have to cut them and add some spades.

Have a search on the forum for NC21 problems and message some NC21 owners and see what their neutral switch looks like..

-Edit-

Had a quick look at the NC24 diagram, the block that houses the Neutral Switch (ニュートラルスイッチ) also connected to the Oil Pressure switch (オイル圧力スイッチ) and the Pulse Generator (パルスジェネレータ )

You'll see them in the lower right hand corner of the diagram. I'm goign to presume that four of the wires in your other plug are the pulse generator wires and the other one is a neutral switch.

They may even be the same colours, just match them up, if not a little educated guess work is in order.