Fuses

[Waggles]

Hi all. No real probs with my F1 but have had several blown main fuses. No real clues from when they happened, Once could have been indicators, other times just during running or as i stopped on driveway. Fuses r new, can check stuff with multimeter etc but this takes time. just wondered what most common cause likely to be?

[Bitsa (Ralph Wright - RIP)]

Waggles,
Being an ex wireman on tornado Aircraft I love fixing electrical problems.If your main fuse blows diconnect all that have a positive suppy,ie regulator, rectifier,brake light black wires and coils.Turn on switch and if not blown start connecting things one at a time until pop.In the extreme I have had to open the whole harness only to dicover a major short between positive and earth.You could start by doing an ohms test on the terminals off the battery.Probe on positive the other to the frame if closed circuit 000 on dial you have a direct short some where if 01234 or whatever its fine.The last bike I repaired for a mate blew fuse as soon as you turned on the switch disconnected the rectifier stoped blowing,fitted new one problem gone.Hope this helps you.
Cheers
Bitsa

[Lobo]

...further to Bitsa's advice, as you bring each item 'back on line' give the component / loom / harness / bundle / everything etc a good, er, Waggles.... particularly if its a gremlin type problem.

And don't get lazy (!)  & replace any fuse with an over-rated spec - unless you fancy bigger probs / loom replacement etc!

Good luck,
Simon

[hairygit]

I had similar problems with my F1 a few years ago. After much cursing and dangerous moments (total loss of power, engine, lights, everything on a rainlashed dual carraigeway at night:'() it was traced to a dirty fusebox causing excessive resistance and blowing the main fuse. Took it off, (2 bolts and a block plug) and soaked the box and plug in mild acid  (vinegar with as much salt as you can dissolve in it)  Result was clean shiny copper fuse holders and connectors, with no scrubbing or scraping, and no further electrical problems (also worth dunking the block connector on the loom in a glass of the same)  A smear of vaseline on the now clean parts will help prevent it happening again.

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[Waggles]

Thanks guys. Unfortunately fuse only blows after week or so once fuse replaced ( with same value only! ) its ok so problem is intermittant. fuse holders are nice & Clean but i havnt checked the box connector so will start there. will also check wiring diagram to see what goes through 15a fuse as the smaller ones have never gone. always suspected it would be dirty connector just wondered which are most likely.

[LesterPiglet]

15a fuse is from the battery/solenoid/starter to the ignition switch. I think if there's going to be a problem it's at the switch or it's associated wiring connections.

[Waggles]

Update. Had a play today. Cleaned the fuse box and its block connector. Did the same with the ignition switch which I sprayed switch cleaner into as best as I could. Unfortunately I won't know if I have cured problem for a few weeks. One odd thing though there was signs of heat at one end of fuse only this kinda makes me think it could be that which was causing problem. It didn't seem dirty but have cleaned it up anyway. Could be a problem with the solder on the back of the fuse holder perhaps?

[Waggles]

... well I got to work OK this morning so at least I haven't made it worse 

[hairygit]

Glad to hear it! The signs of melting you described are exactly the sama as I had, caused by excessive resistance from dirty contacts, causing a greater load to be drawn for the lights etc, and occasionally blowing the main fuse. After cleaning properly it never happened again, so let's hope it's the same for you

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[Bryanj]

Extra problem is every time it gets hot the plastic of the box deforms a bit and the fuse connection gets worse, unless you are a real stickler for originality a new blade type fusebox from vehicle wiring products is the best idea

[Waggles]

I'm not THAT much of a stickler for originality to be honest and I just looked up the price for a new original one which has made me even less of a stickler! ( around 50 euros ) hopefully the extra cleaning will have done the trick - no problems yet this week he said touching wood - but will look for a suitable blade type if it goes again.

[Waggles]

Not really wanting to 'bump' this back up again but thought it might be useful for anyone searching in the future to note all has been well since cleaning fusebox, ignition switch and all connectors thereon.

Obviously I am unsure which actually was causing the problem but my money was on the fusebox if I have to guess