H1 Electrics - Questions

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Chazzman_bm
Posts: 40
Joined: Sat Apr 22, 2006 2:43 pm
My Bike: ZXR400 H1
Location: Scotland

H1 Electrics - Questions

Post by Chazzman_bm » Sun Oct 27, 2019 2:04 pm

So folks,

The old H1 is finally getting some love and I have spent the last couple of weekends in the garage. Along with the braking system, I have been trying to get the bike to run. It has been sitting for a while so it hasn't fired in over a year and hasn't been run in a lot longer than that. In any case, the last time it fired, I had to bypass the fuel pump relay to get fuel to the engine. I bought a second hand relay but it still doesn't so I've just ordered a brand new one from Kawasakioriginalparts. Fingers crossed that fixes the problem.

What it has done though is made me want to learn more about the H1's electrics so I am studying the diagram from Bannerman. Thanks for that! It takes away a LOT of the headache. I have a couple of questions though around some of the electrical bits on my bike.

1) As the H1 is a Jap import, is the CDI different than the UK models? Is it restricted in any way?
2) I have a red box at the front of the box with "PoshFirm" on it and I have no idea what it is for. Does anybody have a clue?

Thanks.

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banner001
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Re: H1 Electrics - Questions

Post by banner001 » Sun Oct 27, 2019 6:43 pm

1. All the h models are imports, none were ever officially sold over here so all the CDi are jap restricted.

2. That box will be a 180kph de restrictor box, it fools your CDi I to thinking you never go over that speed. If you are on mph clocks you will need to keep it, if you have kph clocks you can leave it connected to go more than 180kph, or connect it back into the kph clocks to limit yourself to 180kph.

I would be tempted to say use my diagram, remove your old loom and make yourself a full replacement... No better way to learn than by doing a full loom...i can make one but will need to charge for time and materials.
UK ZXR400 L3 (1993) - Fully restored and on the roads, my green beast!
JPN ZXR250 A2 (1990) - Revs to 19,200rpm... 'nuff said :smt003

Chazzman_bm
Posts: 40
Joined: Sat Apr 22, 2006 2:43 pm
My Bike: ZXR400 H1
Location: Scotland

Re: H1 Electrics - Questions

Post by Chazzman_bm » Sat Nov 02, 2019 1:38 pm

Thanks for answering my questions Bannerman. I am indeed tempted to make a new loom myself but it seems like an incredibly daunting task. I am all for giving it a go but my first question is where do I get the replacement (correctly colour-coded) wiring and new connectors? ....or would it be safe enough to reuse the old connectors?

There is also the issue of testing the 30 year old components. Given your information about the CDI, I would be more inclined to ditch the H version in favour of an L model with a new loom. .....and the old coils for stick ones. Murray1992 suggested they would give better performance and better starting so that's tempting as well.

Ok, I seem to have talked myself into making a new loom. Have you got a preferred supplier for the wires, connectors, etc?

Thanks.
Chazz.

Chazzman_bm
Posts: 40
Joined: Sat Apr 22, 2006 2:43 pm
My Bike: ZXR400 H1
Location: Scotland

Re: H1 Electrics - Questions

Post by Chazzman_bm » Sat Nov 02, 2019 6:57 pm

I have been reading up on the CDIs available for the different model ZXRs and It's still clear as mud. Although I think replacing the old loom with a new one is a very good idea, I also believe that my CDI unit is faulty so I want to replace it as well. Ideally, I want to get rid of the top speed restriction of the H1 CDI and also get rid of the PoshFirm de-restriction unit attached to my speedo unit. In my mind, having less electrical devices in the signal chain is more efficient and cleaner.

Unfortunately, it's not as simple as I hoped and there are other electrical considerations with things like the speedo (mph vs kph), timing rotors, etc. Another post on here suggests that the blue CDIs (UK models) offer the most power but will not work with the Japanese H model ZXs, i.e. mine.

Now back to my idea of building a new and custom loom. Someone said the blue CDI wouldn't work because it had different circuitry than the red one (I can't remember what that was exactly). If I wanted to use a UK spec blue CDI unit with UK speedo, what other mods would I need to do?

Cheers guys.

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