Pick Up coil query

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RickTaff
Posts: 21
Joined: Tue Jul 28, 2020 1:49 am
My Bike: zxr 750 1991 J1

Pick Up coil query

Post by RickTaff »

Where on a ZXR 750 j1 model is the pickup coil located? Have lent my manual out so cant remember, my hunch is it's on the same side as where the oil sight glass is behind a small black cover? Any help would be great

Also, how difficult are pickup coils to swap out for a new one?
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banner001
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Re: Pick Up coil query

Post by banner001 »

RHS of the engine attached to the end of the crankshaft.

As for replacement if its like every other bike ive worked on, its 2 bolts and its out.
UK ZXR400 L3 (1993) - Fully restored and on the roads, my green beast!
JPN ZXR250 A2 (1990) - Revs to 19,200rpm... 'nuff said :smt003
RickTaff
Posts: 21
Joined: Tue Jul 28, 2020 1:49 am
My Bike: zxr 750 1991 J1

Re: Pick Up coil query

Post by RickTaff »

banner001 wrote:
Sun Sep 27, 2020 4:54 pm
RHS of the engine attached to the end of the crankshaft.

As for replacement if its like every other bike ive worked on, its 2 bolts and its out.
Excellent cheers, just had a look and its where i thought, near the area you fill it with oil. Can see the wires coming from behind the casing cover.

I replaced one of the ignition coils month or so back because i was only running on 3, and after installing new coil i was back running on 4. Today now I have had another test of the coils and cylinder 1 and 2 are sparking, 3 and 4 arent. Swapped coils over and still 1 and 2 spark, 3 and 4 dont. So i know both coil packs are working fine. Both of them get 1 and 2 to spark, neither of them make 3 and 4 spark

Friend suggested maybe its the pickup coil, but i thought wouldnt i have no spark on all 4 if it is the pickup?


Only thing changed since it was running on 4 is battery charge has dropped, i aint charged it for a month or so and bike been sitting.
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banner001
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Re: Pick Up coil query

Post by banner001 »

Pickup coil would cause both coils to fail.

As you can swap the coil packs and the problem does not move, then your issue is wiring.

I don't know the 750 wiring, but going to coil pack 1 and 2 will be 2 wires. 2 of these will have the same colour and go to each pack, eg.

Pack 1 has red and black wires
Pack 2 has red and blue wires

In this case the red wires are identical and both should have 12v to them. The black and blue wires would go back to your cdi, I would think there is an issue with these wires or maybe the cdi?
UK ZXR400 L3 (1993) - Fully restored and on the roads, my green beast!
JPN ZXR250 A2 (1990) - Revs to 19,200rpm... 'nuff said :smt003
RickTaff
Posts: 21
Joined: Tue Jul 28, 2020 1:49 am
My Bike: zxr 750 1991 J1

Re: Pick Up coil query

Post by RickTaff »

banner001 wrote:
Sun Sep 27, 2020 7:33 pm
Pickup coil would cause both coils to fail.

As you can swap the coil packs and the problem does not move, then your issue is wiring.

I don't know the 750 wiring, but going to coil pack 1 and 2 will be 2 wires. 2 of these will have the same colour and go to each pack, eg.

Pack 1 has red and black wires
Pack 2 has red and blue wires

In this case the red wires are identical and both should have 12v to them. The black and blue wires would go back to your cdi, I would think there is an issue with these wires or maybe the cdi?
So my suspicion is right, if it was bad pickup coils, all 4 cylinders would show no spark?

Pack 1 has red and black wires, pack 2 has red and green.. So Pack 1 goes to cylinder 1 and 4. Pack 2 goes to 2 and 3 (i think)

1 and 4 showed spark 2 and 3 didnt. Swapped the wires round so pack 1 now fired 2 and 3, and pack 2 fired 1 and 4 and again, exact same cylinders showed spark, and 2 and 3 did not. Thats why i knew both coil packs were working ok.

Just baffling me how it could have changed from firing on all 4, to 2 when the bike hasnt even been started since i last tested them haha. Been sat under a cover, not even had a key in ignition. CDI easy to test?
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banner001
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Re: Pick Up coil query

Post by banner001 »

Cdi impossible to test.

Check for wiring faults.

With the ignition turned on you should have +12v going to both red wire. Check this on pack 2 (to coils 2 and 3)

Check the connection from coil to green wire for corrosion and a good solid connection, check green wire back to cdi for continuity, check the connector block into the cdi where the green wire is for corrosion.
UK ZXR400 L3 (1993) - Fully restored and on the roads, my green beast!
JPN ZXR250 A2 (1990) - Revs to 19,200rpm... 'nuff said :smt003
RickTaff
Posts: 21
Joined: Tue Jul 28, 2020 1:49 am
My Bike: zxr 750 1991 J1

Re: Pick Up coil query

Post by RickTaff »

banner001 wrote:
Sun Sep 27, 2020 9:56 pm
Cdi impossible to test.

Check for wiring faults.

With the ignition turned on you should have +12v going to both red wire. Check this on pack 2 (to coils 2 and 3)

Check the connection from coil to green wire for corrosion and a good solid connection, check green wire back to cdi for continuity, check the connector block into the cdi where the green wire is for corrosion.
Thats a sucker, suppose theyre not overly expensive to buy. Did check ebay and quite a few around for zxr 750... Some dont specify whether they are J model, L, H etc unless they'd be interchangeable?

Will check voltage after work, friend of mine who rides bikes is an electrician so who better to ask :D

Lets hope the red wire on pack 2 shows 12V... if it does i know the issue is simply the green wire then. I'd not be surprised if something has popped loose where we have been re-routing the loom. OR as you say, could even be a bit of corrosion needs cleaning off
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