Topic: Blew a fuse AGAIN!! What could have caused it???

[markiemark]

Hi all,

Blew a fuse today.  Was cruisin around and bike just shut off.  Switched out fuse, bike seems fine and got me home ok.

But what may have caused it?

I seem to have had a lot of trouble with the electrical on this thing.  When I first got it, it wouldn't hold a charge very long, so I switched to a new battery.  Worked ok.  Then I went on an all day ride on some windy roads, some freeways, etc. and it died at the end of the day.  Same thing, blew a fuse.  Switched it out, it rode sorta rough but got me home.  Took it to Lossa since he's in my neighborhood, he said the rectifier was shot and the connections to the spark plugs were corroded.  Fixed all that and it was fine, until today.

The weird thing is that both times the fuse blew it was after I'd been riding for a good long while.  On sunday I rode a long way, on freeways, in traffic, all the above, then today it died, similar to the first time it blew after a long hard ride. 

Thoughts?? I appreciate it.  I'm supposed to be taking my 800 mile road trip that I've been planning for weeks this saturday, I'm gonna be super bummed if I cant fix it before then!!!

[dtmmil]

Check your alternator output, if your reg or rect are bad and its overcharging it will blow the fuse. How about your connections. I had trouble with mine, the main red wire down by the reg/rect where it connects in the white connector had corroded and was shorting out inside the connector, it got hot enough to melt the plastic connector. I have seen this on a couple bikes.

[markiemark]

interesting, the plastic tube that the fuse is housed in was a bit melted inside where the leads cover the fuse, is that what you are talking about?

[GammaFlat]

Your problem is likely corroded connections (more on this below) and a crappy fuse holder.  To fix the fuse holder, clean where the fuse holder comes into contact with fuse.  HondaMan says a 22 caliber rifle cleaning brush will do.  Also, bend the clips inward to make them "clamp" harder. 

On to connection problems.  The connector for the fuse holder should be taken apart and cleaned well.  Better is to replaced all of the connector parts... try here: vintageconnections.com for parts and tools.  Also, check ALL other connectors - rectifier connector, engine to wiring harness and voltage regulator connector.  Also, clean up the green wire to the frame right near the seat latch (on K0-K6). 

You might also want to buy a new fuse holder from HondaMan.  He makes outstanding products. 

[Spanner 1]

Another member who keeps his bike model/year secret  .... hard to help without that info 

Crappy fuse it is, bud........ I would replace with a blade auto. type ( 15A ). Available @ your nearest auto parts place . A single insulated fuseholder with pigtails would be best  OR  shine the stock one on your bike and squeeze the fuse clips together for a tight grip on the fuse....but any doubt about the connection, then replace with above.......

[dtmmil]

You can rewire the fuse box pretty easily also, go to an auto parts store, most of them have a 5 fuse universal flat blade fuse panel for a couple bucks. Or do like Spanner 1 said and get a wire in fuse.

[markiemark]

Another member who keeps his bike model/year secret  .... hard to help without that info 

my bad, my bike's a '73 Honda cb500, about 4500 miles on it.

Sorry, I'm a noob, the fuse you're talking about, is it like this one?  If so, how would i switch from the original tube type fuse to this one? What with the wiring and all?

Thank you

[bollingball]

For a fuse like you pictured get a holder like this

http://www.radioshack.com/product/index.jsp?productId=2102783

Cut the two wires that go to the fuse on the bike and tie them to the end of the new fuse holder. put 15a fuse in new holder It is simple no degree needed That may get you through your trip when you get back go over all your connections and install HondaMans fuse block. If were me I would do it(new fuse block) before the trip.

[Kinch]

Remove the gas tank and pop open the seat, check all connections for anything touching the frame from the horn to the back signals.

Check the grounds, make sure they are clean and connected tightly.

[HondaMan]

Another member who keeps his bike model/year secret  .... hard to help without that info 

my bad, my bike's a '73 Honda cb500, about 4500 miles on it.

Sorry, I'm a noob, the fuse you're talking about, is it like this one?  If so, how would i switch from the original tube type fuse to this one? What with the wiring and all?

Thank you

An auto parts store will have a heavy-duty 1-fuse holder that will fit the CB500 nicely. Make sure the wires to the fuse are heavy, at LEAST 16 AWG size, as the 500 has just the one fuse for the whole bike. There are many similar fuseholders out there that will fit those fuses, but have dinky, light wires. Then THEY become a fuse, another bad day's ride...

[markiemark]

Sorry in advance if this seems like a completely naive idiotic noob question, but when you guys say to check the connections, what exactly are you referring to? Like the plastic connectors?  The Wiring? Or just look them over for corrosion?  What do I do if I see corrosion?

[Kinch]

Sorry in advance if this seems like a completely naive idiotic noob question, but when you guys say to check the connections, what exactly are you referring to? Like the plastic connectors?  The Wiring? Or just look them over for corrosion?  What do I do if I see corrosion?

Anywhere the wire is grounded (green wires throughout the bike & large black wire from battery - connected to the mounting bolt south of your left side-cover) or connected (the covered brass bullet connectors).

You may as well check the wires themselves as well, sometimes a wire jacket can be split and the actual copper can be touching the frame, causing a short and blowing a fuse.

Corroded connectors need to be cleaned (maybe with a bit of dielectric grease applied before reconnecting) or replaced. Ground wires/connectors and areas where the ground wires connect to need to be clean of oil and corrosion as well.

Look out for cooked connections as well.

[zackblack]

Just an fyi:

Everything was running fine on my bike - then suddenly I started blowing fuses all the time.  Turns out one of the black wires from the right hand control was pinched and every once in a while the wire would touch the handlebars (this was all happening inside the control).  I assume that the constant use of the throttle would minutely move the wire until it grounded out and blew the fuse.

I fixed it by cutting at the pinch, re soldering and using a double layer of heat shrink tubing.

[markiemark]

Cool.  Big thanks to everyone.  Gonna check everything tomorrow when there is sunlight.

[bollingball]

I don't like the one fuse I would at least put the headlight on its own fuse. Going 60mph at night in a curve fuse pops = no lights

[markiemark]

Happy to report, had the fuse changed to a blade type and everything else looked good.  Now to buy a handful of fuses just in case and I'm off on my road trip Sat morning!!!

Thanks all for your help!

[bollingball]

Good to hear have a safe and trouble free trip.

[Duanob]

Check this guy's site out. I've been buying connectors from him and slowly changing out connector blocks and main wires. I had a charging problem and it turned out to be bad wires. I am thinking of using the fuse block he sells, it's the 4 blade type.

http://www.oregonmotorcycleparts.com/connectors.html

On the subject of fuses where does one find the Honda type that come on our bikes? The AWG type are a bit long for the fuse holders. I did find Some 14 AMP fuses that fit perfect at NAPA but the 7.5 and 5 amp fuses I can't find in hte shorter length.