748 probelms

Discussion in 'Technical Help' started by Clarkyboy, May 29, 2013.

  1. HI All, I have a problem with the 748, it wont start, light up anything, or even give me ignition lights, the battery is good, voltmeter says so, and the other battery gives the same result. about a month ago I put my bike back together, fitted a new rectifier, all good and working perfect, replaced the yellow wires with heat proof heavier duty ones, bike has run sweet as a nut, however, I had forgotten to put the battery drain pipe back on, which meant acid dropped onto the main relay and melted the top of it, I changed the relay and the bike is still dead! the only other thing I have done is change a light bulb (and even i'm not that bad with wires to kill the bike doing that!!) I have had the barrel off, as far as the voltmeter says it works, the wiring from it down to the relays work, I stripped the black insulation off the loom to make sure there were no melted wires, all the fusses are good also, however, I have noticed that the main fuse (green 30amp) has not power running through it!? can anyone help or make some suggestions as to what I can try, right now its like the battery isn't on the bike! and as a side note is does not have an immobiliser etc. Thanks... oh and my 'return' key has stopped working, hence the shit punctuation!!!!
     
  2. Which new reg/rec have you fitted? I'm interested because of the 30Amp fuse not showing power.

    Check the battery to engine and frame earth points as well.

    AL
     
    #2 Ghost Rider, May 29, 2013
    Last edited by a moderator: May 29, 2013
  3. there will hopefully be a ton of helpful answers along soon as there are so many possible culprits here and 'methodical' is usually the key. I'm going to go for the obvious but easily overlooked connector onto the battery itself. It probably isn't this but the symptoms fit and i've had it happen half a dozen or so times in my lifetime. The connector and/or the battery terminal get a grimy deposit on them enough to make junction stay open circuit despite being tightened down.
     
  4. Clarkyboy, by 30A fuse I assume you mean the 30A fuse in the fusebox and not the 30 or 40A one on the regulator circuit. Check the 30A fuse then if it is good disconnect the battery and test the continuity between the battery side of the main 30A fuse (red wire not white) in the fuse box to the battery + connection lug. It should beep or have no resistance. If it does not, you have a broken or disconnected wire in there somewhere. If you get continuity you need to reconnect the battery then pull the 40A relay out noting where pins 87 on the relay fit into the relay socket. Check for 12v at the relay socket at pin(s) 87, you should get 12v on one of the two connectors correspoding to pin 87 which is the feed from the fusebox, main fuse and battery to the load side of the relay. This part of the circuit is always live up to the ignition switch with the battery connected. If you get no 12v signal at either of those connections you have a broken wire from the fuse box to the relay.
     
    #4 Denzil the Ducati, May 29, 2013
    Last edited: May 29, 2013
  5. Thanks for the responses guys, the rectifier reg I fitted is a Ducati one, there had been an aftermarket fitted before - rr51, but I had a good spare one so used it, its been working spot on since I fitted it - The fuse I was referring to was the big one in front of the battery, all of the ones in the box have been checked also and are good. the battery terminals are good, its a new battery ( I did this when I changed the reg/rec ) Denzil, appreciate your input - I will follow your instructions and see how I get on! ALSO... WHY DOES MY RETURN KEY NOT WORK!!! lol
     
  6. You need to click on the A/A in the top left hand corner of the reply box
     
  7. If you have changed from and RR51 to a Ducati one, then I suspect that the big fuse wire is disconnected somewhere up near the headstock.....the RR51 disposes of that wire and fuse (well, it does on the SSs).....

    Is there power from the battery to one side of the fuse?

    ....IIRC try looking for a thick-ish black/red wire that isn't connected, possibly on the left hand side below the fuse block.

    AL
     
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