FZR400 to 600 wiring - Advice needed

[IanU]

I am in the process of fitting 600cc 3HE running gear into a FZR400 3en2.

The donor 600 was a stolen recovered bike, with the wiring loom badly cut up, so I have decided to use the 400 wiring loom with the 3HE CDI.
I have just got round to inspecting the two CDI units - The 600 unit has an 8 pin and a 6 pin oblong plug and the 400 unit has a 4 pin and a 6 pin oblong plug, a 5 pin round plug, a red wire and a green wire.
The bike will be using a 600 exhaust without an Exup Valve

How do I get 3HE CDI to fit onto the 3en2 loom?

Are any other wiring mods required?

Thanking you in anticipation.

[willandrip]

You have a couple of things to take into account here.

The round plug is for the Exup servo circuit on the 3EN2 and not required at all on the 3HE.

The single red wire and the single blue/green wire are for the restriction circuit on the 3EN2 that is not present on the 3HE.This needs to be connected to an operational speedometer on the 400 or the TcI does not receive a signal from the speedo indicating speed and the Tci will then limit the engine rpm to 12,500 rather than the required 14,000.

The 400 limiter cuts in at over 14,000 rpm versus 11,500rpm plus on the 600.
It may be possible to over rev the 600 if the 3EN2 unit could be made to operate.
I do not think the restricted (no speed circuit enabled) 400 unit would run a 600 correctly...... the ignition curves will be different.

3HE harnesses are so cheap and easily obtainable in the UK as to make this a very complicated way to run a 4/6 conversion.
For the sake of £25 , I would not even consider the piss on. !

If you are determined...... use the damaged 3HE harness and graft in parts from the 400 harness where the damage is but do not alter it where the Tci plugs in.

[Evilchicken0]

You can run the 3he engine off the 3en cdi, they did it in an old bike magazine, but as stated the 400's cdi will rev higher than the 600 motor.
I'd get a decent secondhand loom for a 3he and keep the others as spares.

Use the whole 400 bike with the 600 engine, downpipes, loom and cdi. The 600 carbsare better to use because they'll be tuned for the engine. You'll need to space the fuel tank cover up a bit (20mm) because the 600 engine is taller.

[DonTZ125]

Guys, you're way over thinking it. He wants to use the 600 TCI with a 600 engine and a 400 harness. So - plug the TCI into the harness. The 6-pin connection plugs right in. Plug the 4-way connector into the left-most pins of the 8-way TCI socket. All the other plugs and wires can be taped up, since the 3HE TCI neither knows nor cares about them.

[IanU]

Many Thanks everyone, I can see a little light at the end of the tunnel now

[Evilchicken0]

Many Thanks everyone, I can see a little light at the end of the tunnel now

Just make sure its not a train