RaceFan wrote:would I require the entire harness to retrofit it?
TIA.

Well, I'll actually answer the question shall I?

Presumably this is to fit to the 28sp you have?

Yes, you will require a PGMII, an R5k/R6k harness, mc18/21 temp sender unit, mc18 clocks (plus speedo cable, ignition barrel and top yoke if it's a road bike).
You'll also require an '18 or '21 flywheel if you want the bike to perform reasonably and it'll require some level of setup as this is at least as big a performance jump as fitting an HRC smartcard.
If you're doing this for power, don't forget the '28 pipes are restricted as well.

Mounting the clocks will require some work, the '18 clock mount doesn't fit the '28 frame and even if it did the front fairing mount bolt isn't in the same place.
The PGMII itself will also need mounting somewhere, it's sits under the passengers seat on an '18.

There are other differences between the '18 and '28, specifically the reg/rec on an '18 is in line between the stator and the loom, the carb soleniods have two plugs not one and the flywheel pickup plug is different.

You can just swap the plasic plug housing over on the flywheel pickups by poking the spade connectors out with a small screwdriver. The wires themselves are the same, it's just the plug shape they changed.
The others can be overcome by a little wiring alteration or by using the '18 reg/rec and/or carb solenoids.

If this is a roadbike you might want to do something about the steering lock.
I have no idea if the rear light plugs are the same, if not swapping them over shouldn't be tough, obviously the headlight will require some work as the mc18 only has one bulb, bearing that in mind i'm not too sure I'd use an '18 reg/rec on a '28 roadbike.

If it's a trackbike you can just splice one of the red wires from the reg/rec into the red/black wire that should run to the ignition barrel, do that and the bikes power will be on the run/off switch.
If you pull all the loom tape off you can then make a decent job of removing all the surplus wiring and ditch the fuse box if you want as you can see where it all really runs. Most of it is for the lights and indicators.

After my PGMIV died and I decided to fit a PGMII to my racebike it took me about an hour to get the loom just lying across the bike, roughly spliced in and the bike running then about another 4 hours to make a tidy job of it and mount the clocks so they didn't foul the fairing.
Here it is after the first hour, just fired up and working.
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