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Discussion Starter #1
Hi ,bike was immersed in water Upto and into alternator due to Storm Desmond.Having replaced the knackered alternator I now have a problem getting dash to light up.Soon as I try lights dash goes blank.Seems as as soon as I have any load on the system the dash goes blank.Sometimes I turn the key and dash doesn't light so may be damaged ignition switch.I want to start from basics and check all Earth contacts are sound.Checked manual and no reference.I have 3 negative cables from battery negative terminal.One goes to back of alternator,one seems to go to the cpu and I have a dynojet power commander fitted and 3 rd Earth wire goes to this.Is the alternator Earth connection the only engine/frame Earth.If not where can I locate any other Earth connections away from the battery is frame etc.
 

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Did you have a look in the Workshop manuals mate. There should be a (-) going to the engine just to the side of the alternator as you said, another which is a whole lot of blue wires sheathed in black connected to the ECU and lots of other connections in the wiring loom.
(You don't have a SPU on your bike).
Then you should have another connection to the frame at the back near the ECU.
 

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Discussion Starter #3
Hello Donsy,thanks for reply.Ill have a look at the frame near the ecu .Yes no spu or cpu meant ecu.ps looked in manual and doesn't describe the locations just shows Earth symbols on wiring diagram but not exactly where Earth wires go to Earth.ps I am not good with electrics but am determined to understand it better.
 

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If your bike has been flooded out then the fusebox area on the rhs of the bike will need attention, the wiring loom running off the back of the fuse box heads up to the dashboard area.

The loom on the 750 is known to collect water due to a bunching after as it is strapped to the frame, carefully remove the insulation outer cover and che k the condition of the wiring, there are some plain old soldered joints in there that are prone to corrosion and that leads to dashboard faults and display blackouts.
 

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Discussion Starter #5
Thanks Jimbo I will have a good look this weekend.Very useful info,that I didn't know.Cheers
 

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This may help you....(it may not, too!)

The circled areas are the grounds that I can find...other than some of the switch bodies that ground through the switch.

F4 750 Electrical Grounds.jpg

F4 750 Electrical Grounds 2.jpg

F4 750 Battery Connections.jpg

F4 750 Schematic Battery Connections.jpg
 

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Oh Chuck, you've become such a picture slut, I love it :mouthwate
Thank you.
YES, Jimbo makes a very good point, it's a well known spot for corrosion right down there by the cylinder head.

I would pull the wiring harness out and clean it up nicely, that copper will be is serious need of love.
Here's a cut down wiring loom, ask any questions, we will try and help.:yo:



All the BLUE wires are (-)
 
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