electrical issue

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Yes, I agree if he meant nothing was working. I assumed that "nothing" meant there was no voltage showing at the white wire at whatever point it was checked.
 
A new battery does not mean a good battery. Load test it before starting on the rest of the fixes. A newish battery nearly stranded me late one night, voltage tested fine but it provided no amps so no lights or ignition, took out the fuse and got home using the 2MC capacitor.
 
kommando said:
A new battery does not mean a good battery. Load test it before starting on the rest of the fixes.
Click to expand...

Yes, as the electrical system was apparently working normally with the "new" harness sections before the lay-up (assuming they were new then and not fitted since?) it could be due to a faulty battery.

One way to load check would be to temporarily bridge the terminal studs of the starter relay (with a spanner, plier jaws, etc.) as the starter motor should then operate if the battery is good.
 
L.A.B. said:
Did you try connecting the ignition switch brown/blue NU (from battery negative) to NG (lights except for the headlamp, Edit direction indicators/blinkers brake light and console warning) and UY (headlamp only and console main beam warning lamp)?
Click to expand...
I didn’t. The brown/blue is connected to the battery +. Is that wrong?
 
fourperf said:
The brown/blue is connected to the battery +. Is that wrong?
Click to expand...
Brown/blue NU connects to battery negative as the standard electrical system is positive earth/ground.

Edit:
electrical issue

Connect only the heavy gauge "Engine Earth" starter positive cable (normally black not 'red' as shown on the Mk3 wiring diagram) to battery positive.
Although drawn on the diagram (crossed out) and a red "Earth" wire with a ring terminal is included in the harness, do not connect it to battery positive if the starter motor is connected.
 
Last edited:
L.A.B. said:
Brown/blue NU connects to battery negative as the standard electrical system is positive earth/ground.

Edit:
electrical issue

Connect only the heavy gauge "Engine Earth" starter positive cable (normally black not 'red' as shown on the Mk3 wiring diagram) to battery positive.
Although drawn on the diagram (crossed out) and a red "Earth" wire with a ring terminal is included in the harness, do not connect it to battery positive if the starter motor is connected.
Click to expand...
Ouch, thanks so much. I am going to do that today. I do have a starter motor. For some reason the br/bl wire with the fuseholder has a ring terminal with red on it. Connected to the neg terminal on the battery is only a heavy gauge black cable which goes to the starter motor via a relay. The positive terminal has a heavy gauge red wire that goes to the engine as a ground and the br/bl wire. Hopefully i did no damage.

when I bridge the terminals of the relay with something metal the starter will operate.

What’s strange is that the heavy black cable that comes from the battery negative to the relay then to the starter has been like that since I restored the bike some 15 years ago and I rode it tons. I assumed I had the br/bl wire connected to the positive battery terminal because it had the red ring terminal on it. It’s been so long since I had taken the battery out
 
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fourperf said:
The positive terminal has a heavy gauge red wire that goes to the engine as a ground and the br/bl wire.
Click to expand...

Yes, there's the problem. The heavy gauge engine cable is correct. The brown/blue on battery positive is definitely not correct.

fourperf said:
Hopefully i did no damage.
Click to expand...

As you hadn't completely reversed the battery polarity then it should be ok.

fourperf said:
What’s strange is that the heavy black cable that comes from the battery negative to the relay then to the starter has been like that since I restored the bike some 15 years ago and I rode it tons.
Click to expand...

That is correct, and nothing strange about it so don't move the heavy gauge black battery-relay cable from battery negative.

All you should have to do is move the brown/blue to battery negative.

I sleeve the brown/blue and heavy relay cable together to avoid mistakes.
 
Success, thank you so much! One more question. When I stopped riding the bike it had new oil in. I have an anti-drain valve for the oil. The oil still did run and it’s in the sump. Do you think I need to drain it from the sump or can I run the starter with no gas and no spark plugs in the head to try and pump the oil back into the oil tank?.
 
fourperf said:
Success, thank you so much! One more question. When I stopped riding the bike it had new oil in. I have an anti-drain valve for the oil. The oil still did run and it’s in the sump. Do you think I need to drain it from the sump or can I run the starter with no gas and no spark plugs in the head to try and pump the oil back into the oil tank?.
Click to expand...
I had a crank seal in primary break apart from kick starting after significant amout of wet sump oil in cases.
Check if your oil screen at bottom of oil tank is exposed (ie all oil in sump). If level is only down a little, you should be ok.

Btw, what type of anti sump valve? Just the stock MK-III type in timing cover or is there an external type (manually operated or spring loaded)? Spring loaded types known to be trouble and risky. I've got manually operated with an ignition power interupt as failsafe.
 
Plenty of topics on here cover the subject well. In essence too much oil in the sump risks pressurising and blowing the crank case to primary seal. There are well engineered breathers fitted to the sump that can avoid this (e.g. CNW), but expensive. I removed my auto anti drain valve. There's a video in one of the threads here, showing how much they can reduce oil flow to the pump. I could see me forgetting to open a manual version! Rather than get the safer version that interrupts electrical power to the ignition, so you can only start the bike with the oil flowing, I went with AN's drain bolt, which screws into the filter in the sump. This allows sumping, but avoids frequent loosening / tightening and wearing of the drain plug threaded into the case itself. You'll get to know your bike, I empty the sump if I leave it longer than a few weeks (which is rare).
 
fourperf said:
When I stopped riding the bike it had new oil in. I have an anti-drain valve for the oil. The oil still did run and it’s in the sump. Do you think I need to drain it from the sump or can I run the starter with no gas and no spark plugs in the head to try and pump the oil back into the oil tank?.
Click to expand...

I suggest you either drain the sump and return the oil to the tank or, add just enough oil to the tank to partially cover the gauze strainer and just start it up (assuming it will start) keeping the revs down until the tank begins to fill.

Mart UK said:
In essence too much oil in the sump risks pressurising and blowing the crank case to primary seal.
Click to expand...

The 850 Mk3 has a circlip retaining the primary seal therefore, theoretically, the seal shouldn't blow out from crankcase pressure.
 
L.A.B. said:
I suggest you either drain the sump and return the oil to the tank or, add just enough oil to the tank to partially cover the gauze strainer and just start it up (assuming it will start) keeping the revs down until the tank begins to fill.



The 850 Mk3 has a circlip retaining the primary seal therefore, theoretically, the seal shouldn't blow out from crankcase pressure.
Click to expand...
My seal did not pop out (MKII) but actually split in two. The lip separated from the metal ring. It was likely original and embrittled, but the wet sump pressure killed it. First indication of problem was oil out the primary at felt "seal" , coating back of bike and tire.
 
Tornado said:
I had a crank seal in primary break apart from kick starting after significant amout of wet sump oil in cases.
Check if your oil screen at bottom of oil tank is exposed (ie all oil in sump). If level is only down a little, you should be ok.

Btw, what type of anti sump valve? Just the stock MK-III type in timing cover or is there an external type (manually operated or spring loaded)? Spring loaded types known to be trouble and risky. I've got manually operated with an ignition power interupt as failsafe.
Click to expand...
Thanks a lot Tornado, I have the old britts one that has a spring
 
L.A.B. said:
I suggest you either drain the sump and return the oil to the tank or, add just enough oil to the tank to partially cover the gauze strainer and just start it up (assuming it will start) keeping the revs down until the tank begins to fill.



The 850 Mk3 has a circlip retaining the primary seal therefore, theoretically, the seal shouldn't blow out from crankcase pressure.
Click to expand...
Thanks so much!!
 
Tornado said:
Hopefully this will persuade you to toss it:

Click to expand...

Yep. Well done, that's the video that prompted me to remove mine. Not a real world test, but it's so little trouble to drain the oil, I decided why take the risk.
 
"if it's good enough for Velocette, it's good enough for me"
So, it can be seen that IF the oil in the line between the anti-sump valve and the oil pump drains past
the pump into the sump, where is the suction to open the spring loaded ball valve? It can be supposed
that without head pressure of oil from the tank that the oil in the pipeline will not drain past the pump.
Now, I did have one of these installed on my Commando for about 6,000 miles and nothing bad happened. But, I saw
the light and removed it to the trash bin, replacing it with a positive on/off valve with an ignition interlink
which I open 10 minutes before starting the beast to ensure that the pump has received oil. Of course there are
naysayers who suggest that my engine will blow up due to an interlock failure. That would mean that both I
and the interlock failed simultaneously. You think the commercial jets you travel on don't have similar fail/safe
devices?
 
lazyeye6 said:
"if it's good enough for Velocette, it's good enough for me"
So, it can be seen that IF the oil in the line between the anti-sump valve and the oil pump drains past
the pump into the sump, where is the suction to open the spring loaded ball valve? It can be supposed
that without head pressure of oil from the tank that the oil in the pipeline will not drain past the pump.
Now, I did have one of these installed on my Commando for about 6,000 miles and nothing bad happened. But, I saw
the light and removed it to the trash bin, replacing it with a positive on/off valve with an ignition interlink
which I open 10 minutes before starting the beast to ensure that the pump has received oil. Of course there are
naysayers who suggest that my engine will blow up due to an interlock failure. That would mean that both I
and the interlock failed simultaneously. You think the commercial jets you travel on don't have similar fail/safe
devices?
Click to expand...
I can add that starting within a minute or two of opening my manual AWS valve gives full pressure (40-55psi) at the rocker spindle cover where my oil gauge tee's from. So no worries of priming delay that i've seen.
 
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