750SF3 Fuse Holder

Skeeta

Skeeta

Junior member
Location
Coolum Beach, QLD
Gday,
Could some one tell me the Fuse Ratings (amps)and x4 positions on the 750SF3 Fuse Holder as pictured, from left to right
Thanks
Skeeta
 

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If it blows, it ain't strong enough.
If the wire melts, it's too strong.

Probably simply 16 and 8 A.
Circuit has obviously been tampered with anyway.

Paul
 
A photo of an empty fuse holder isn't very helpful. With 40+ year old bikes, who knows what alterations have been made to the electrical system?
I wouldn't even be confident that all bikes left the factory with identical fuse locations.
You really need to identify what circuit(s) each fuse protects. 

Anyway, as a general guestimate ?
Charging circuit (between regulator and battery 20 - 25A
Other circuits 10 - 15A
 
I would have thought there was some commonality for the standard bike leaving the factory ?? Not withstanding post modifications carried out by consecutive owners
Skeeta
 
Skeeta said:
I would have thought there was some commonality for the standard bike leaving the factory ?? Not withstanding post modifications carried out by consecutive owners
Skeeta
Click to expand...
There was, they left the factory with 4 x (white) 8 amp fuses.

Marnix
 
OK, it's just my opinion, but that fuse holder and wiring looks like a problem waiting to happen. Why not change it to a modern blade type fuseholder 'while you're at it'?

Cheers

bazzee
 
bazzee said:
OK, it's just my opinion, but that fuse holder and wiring looks like a problem waiting to happen. Why not change it to a modern blade type fuseholder 'while you're at it'?

Cheers

bazzee
Click to expand...

If the rivetted connections are still firm and the plastic body shows no fracturing, there's really no reason why it shouldn't go on working for another decade or five.  Keep the old type clean and ensure the connectors are tight, they'll last forever.  Oh, and don't send 100 Amps through them. :D

It's the buggered-by-previous-owner items that turn out to be dodgy and cause problems. 

Wiring is a different issue altogether... ::)

piet
 
We took a number of 40 year old bikes to the tip of Australia, mostly corrugated roads and tracks.

Biggest problems were in the main, broken electrical wires. The brittle old buggers found the going too tough. And almost always broke in the most obscure places. Bar the XL250, that sheared the wire from the battery to it?s remote fuse holder so many times we looked there first, every time it konked out.

If ithe bike is stripped down that far, I?d swap out the loom for a new one.
 
sfcpiet said:
If the rivetted connections are still firm and the plastic body shows no fracturing, there's really no reason why it shouldn't go on working for another decade or five.
Click to expand...

When I resurrected my brother's 3C and went to clean up the (two) fuses, both of the little springy fuse holder tabs fell off. Not sure what made them so brittle.
 
I used that std Bosch fuse holder for the 4 decades my bike was running. No probs - as Piet says, keep the contacts clean and in good nick. Replaced most of my wiring bar the basic loom of about 4 wires after 30 years. New custom bike will have modern blade fuses, an alternator, Ignitech ignition, Dyna coils etc etc - you get the picture.

Personally I don't like the look of your connectors - I will NEVER use those car type connectors with the plastic sheath; the wire is the only part crimps and they will break at the place where the plastic insulation ends and the bare wire begins (inside the crimped bit). Double crimp (one crimp for the wire, one for the plastic insulation) brass connectors fitted with a professional grade crimping tool. Some owners also solder every crimoped section. Shrink tubing for isolation where nec.
 
Never had a problem with the original fuse holder, but i do maintain them and witl give the wiring a health check which normally shows up something dodgy.
  Infact the first thing i replace on a new to me bike is the earth and power cables.
Regards Andy
 
If you want some wiring Inspiration have a look here. I really like the length long split sheathing about the middle of this thread plus some of the Marine rated bits used.
https://advrider.com/f/threads/here-we-go-again-yet-another-bmw-r1150gs-adventure-ural-sidecar-renovation.1428469/
 
Don't use any sort of connector on those Bosch fuse holders.
Just bare the end of the wire and screw it down.
That's what the factory did 50 years ago.
Paul
 
I have to disagree that those old type fuse holders are still good. It maybe depends on the environment the bike has spent it's life in. My SF was in the wet tropics and could stay moist for weeks on end. Mild corrosion over the terminals (which I was constantly cleaning/buffing off) for the fuses caused voltage drop and no end of problems. A bike in a dry climate might be ok with that fuse holder but after 40 years an upgrade can't be a waste of money. I also agree about old wire, a lot of it will be black throughout inside the insulation which itself will be brittle in places.
 
Paul Marx said:
Don't use any sort of connector on those Bosch fuse holders.
Just bare the end of the wire and screw it down.
That's what the factory did 50 years ago.
Paul
Click to expand...

Uh, uh... wire ends were tinned.  Can be seen on NOS looms.

Time has proven that solder isn't the best solution.  Wires tend to rot where the solder stops, partly corrosion, partly vibration.  Ferrules over the bare wire ends avoid corrosion that is induced by solder flux residue, the plastic extension affords a bit of support to the wire.  Almost as reliable as a (properly) crimped connector.

Lee, I wouldn't claim that all those old type fuse boxes are OK, there are loads out there that belong in the trash.  But, a well-kept example can live on for quite a while.  My own GTL still carries the fuse box that was fitted at the factory, nothing corroded, nothing loose.  It has been reliable for the past 25 years that I have owned the bike, I see absolutely no reason to replace it.

piet
 
sfcpiet said:
Uh, uh... wire ends were tinned.  Can be seen on NOS looms.

Time has proven that solder isn't the best solution.  Wires tend to rot where the solder stops, partly corrosion, partly vibration.  Ferrules over the bare wire ends avoid corrosion that is induced by solder flux residue, the plastic extension affords a bit of support to the wire.  Almost as reliable as a (properly) crimped connector.

Lee, I wouldn't claim that all those old type fuse boxes are OK, there are loads out there that belong in the trash.  But, a well-kept example can live on for quite a while.  My own GTL still carries the fuse box that was fitted at the factory, nothing corroded, nothing loose.  It has been reliable for the past 25 years that I have owned the bike, I see absolutely no reason to replace it.

piet
Click to expand...

I'll have to put my Swiss army knife away. No more cutting and stripping wires.

Kidding apart, I've been riding my faithful SF2 since 1992, and the fuses that were in it then are still there.
Probably original Breganze stuff.

Can sell the fuses if interest is sufficient.

Paul

PS: I've put a blade type fuse holder on the S, the original was falling apart.
The part is still available.
 
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