[AvidSV650Rider]

I was just sittin' around with a couple of friends talkin' motorcycles.  One of them had just bought a '77 CB750; the other has a CB750 custom fitted with a 2004 CBR1000RR exhaust undertail exhaust.  As they were admiring my SV, I mentioned to them that I had a feeling this was gonna the (academic) year that I would have to stick money into the bike for repairs.

Not more than 45 minutes later while I was riding, my friend Chris noticed that my tail light wasn't working properly.  It illuminates normally when the brake lever/pedal is not pressed.  However, the rear brake pedal has no effect and when the front lever is depressed, the light does not get brighter.  As the lever is released, there is a certain point when the tail light will brighten.  When the lever is fully released, the tail light returns to the standard illumination.  Anyone have this problem?  Anyone have tips or hunches on where I should start?

Also, today when I tried to sound the horn to get a friend's attention, the horn would not sound.  When the bike is off, I can hear the horn make a bearly audible chirp as the horn button is released.  Go figure....

Any ideas?  I haven't checked on anything yet, I was going to try to get to that tomorrow...

 

[evilbologna]

Get the tail section off and starting trailing the wires back to their source. Electrical problems aren't exactly fun. As for the horn, it could be the same thing (bad connection) but horns can die and require replacement.

 

[Zanetti]

Check the simple things first, like the switch adjustments on both levers. Another trick is to seperate and re-connect the electrical connectors, starting at the tail lght, checking for correct operation each time. Sometimes a little bit of corrosion or crud is on the connector pins, and the act of disconnect and re-connecting will clean them.

 

[Benda]

try cleaning the connections on the buttons for each brake and your horn. i had a similar problem with my starter button not working and used pb blaster to clean the connection and it's back to normal now.

 

[blkvwgolf]

my horn does that intermittantly and has since i had bought it... sometimes it works sometimes it doesnt... let me know what your solution is... I think I will be going with Hella air horns mounted somewhere under the airbox.

 

[AvidSV650Rider]

So the horn and brake light magically started working again today, just when I went out there to track the electrical bug down. Great. :/

 

[evilbologna]

So the horn and brake light magically started working again today, just when I went out there to track the electrical bug down.  Great. :/

You weren't popping any fuses right? The CBR F4i would pop a fuse everytime I hit a big bump. After tearing the whole thing down, checking every wire in the circuit that was shorting, I finally found it. A tiny screw, like the ones in glasses, was loose inside the tail light bulb housing. Over large bumps it would jump around and land on both contacts.

 

[Zanetti]

Intermittant electrical stuff, they're the most fun to track down.   ;D

 

[Basskrieg]

try cleaning the connections on the buttons for each brake and your horn.  i had a similar problem with my starter button not working and used pb blaster to clean the connection and it's back to normal now.

Could be an intermittent ground somewhere or like Benda said a bad connection somewhere. Try turning on the ignition and just be methodical on moving each wire, especially where there are connections and try to find the spot. Either use a good electrical contact spray cleaner or a little wire brush where you can.

PS: and dont forget to clean and tighten the battery teminals and such.

Good Luck.

 

[Bloodhound]

Moisture possibly?

I would start checking plugs, hit 'em with some contact cleaners and look at the micro-switches on the brakes and contact for the horn.  I get uneasy with Suzuki's wiring woes anymore, I had a '83 gs550e to get me around while I was in the service and it ate 3 wiring harnesses in as many years.......Also you got around to checking yer "passing lights" switch yet? Hopefully the problem won't rear it's head for again this season.