Fuse Box Dissassembly - 1991 to 1994 model

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The L5 onwards is similar, but it has a few more circuits, the L9 is more complex again. I think this has been done before...but i cant find it so apologies if its a duplicate.

Reason for doing this, im putting my bike back to mint condition and want to 1. get rid of the copper oxide corrosion properly and 2. make sure the internals are as good as the externals.

This is my pin arangement - also 1/3rd of these are redundant in the L4 so these will be removed and the holes plugged with sealant:


First you remove the rubber damper, the cover and the fuses, then you drill out the 4 plastic plugs - only need to go in a few mm:


You can then pop off the bottom and finally the top to reveal the components:


Desolder all the pins holding the main connection block in:


Finally you will want to desolder the relay and the 3 diodes:


Clean the board, clean all of the plastics, clean the electrical connectors, change the diodes for new, and the relay if desired and solder it all back together, with sealant to hold it all together.

This is an example of a fusebox that i bought thats functional, and looked good from the outside...

- ive just measured the damage, thickness of the board is 1.60mm, the areas that are corroded are 1.46mm deep...

Im currently designing an L4 specific PCD board, if i can get them for a decent price ill order a few and sell them on here cost price...

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Final finished design, needs to be printed so i can make absolutely sure that its correct, but from my testing so far its pretty much bang on.

Ill post up a price for the finalised item once i make them, now im off to Ebay for PCB's and ferric chloride...i already have a darkened oven, uv-photoemulsion and a UV exposure unit...

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I can now make PCB's at home

First you make the positive, print it onto acetate, coat a silk screen with photoemulsion, place the acetate over the silkscreen when dry, expose to 1600W UV light bulb for 12 seconds, remove acetate was and dry...


Pull ink through the screen and heat with a heat gun to harden...


Heated ferric chloride and shaking removes the unwanted copper, then clean with isopropanol to remove the ink


Trim, sand and drill locating holes...


Need to wait for my tiny carbide bits to get here, then i can drill all the rest of the holes, ive fully cleaned all the plastic parts and the old copper pins, then solder and its good to go!

[banner001]

If anyone wants one of these boards ill sell the blank board (i.e. the second to last picture cut into 2 boards - absolutely no finishing done on my side!) for £7 (that's with p&p included), alternatively send my your fusebox and £50 and ill send it back to you in as near-brand new condition (i.e. refreshed copper pins, all clean, new board)

This is currently for the 1991-1994 zxr400 in UK-spec (so one pin extra for the headlight relay), i currently have no plans to do this for the <1991 or >1994 bikes unless demand is massive...

[irishdanny]

hi ,
that fuse box in ur first pic is the exact fusebox on my 91 zzr 400 k2 ,even down to the single relay ,that relay just clicks like mad when i press the start button ,brand new battery ,any ideas and i might be getting one of ur boards,

well done by the way ,u really do beleave in helping others ,,,missing now a days tbh ,

cheers
danny

[irishdanny]

also the 3 diodes in the pic ,what should the be reading on the multimeter ,im getting 535 ish across all 3 of them ,,,any advise plz


cheers
danny

[banner001]

At a rally at the moment, I'll test my spare when I get home.

Are you testing with the diode still on the board?

[banner001]

also the 3 diodes in the pic ,what should the be reading on the multimeter ,im getting 535 ish across all 3 of them ,,,any advise plz


cheers
danny

So I set my Multimeter to diode and tested with the diodes on the board, all gave about 0.55V in one direction and 0V in the other so it's working as a diode, when removed from the board they all gave voltages between 0.6V and 0.65V...but its a diode so none of that really matters, as long as it passes current in the one direction that's all you really need.

[banner001]

Also the relay that's on the board should give a SINGLE click when you thumb the starter motor IF your bike will allow the starter to fire.

The relay is part of the starter lockout circuit, the relay should click under the following conditions:
1. The bike is in neutral
OR
2. The bike is in gear but the clutch has been pulled in.

As long as one of these conditions has been met then when you thumb the starter motor that relay gets power sent to it, it can only go to ground if the above conditions are met, if they are then power is shunted to the starter motor relay and the engine turns over.

The sidestand lockout works differently, you can start the bike as described above with the sidestand up or down, however once the bike is (a) no longer in neutral AND (b) the clutch has been fully let out, if the CDi detects that there is no path to ground through the sidestand switch it will kill power to the coils.

Hope this helps

[Bleb]

Glad I found this! I have had trouble starting the bike (H2) for a while. Thought I'd cracked it in time for the hill climb tomorrow, but it's resurfaced. I'd got as far as a ticking from the fuse box area, so hoping it's the internal relay. Can I safely jump it out of the loop? TIA... Bob

[Bleb]

Dodgy clutch switch! Never even realised it was there.....it'll start with the clutch out!

[banner001]

I might revisit this at some point and put the diagrams on pcbway. I've been thinking that a junction box/fuse box, with no lockout circuits, compatible with the original pinouts might not be a bad thing.

[masterofinsanity]

great work Banner!!