Topic: Help, no ignition on CB550, thought was a fuse but there are none!

[sinister902]

so I tore into the project bike today, to try to find the wiring gremlin that occured due to previous owner jumping the bike off his car (obv. didnt work afterward)....thinking it was a fuse i pull off the sidecover, to find this:. As you can see there ARE no fuses here, just relays and such. so the back side i noticed a plug missing a home, Then i found another one on top of the inner fender liner..Does anyone have any clue whats going on here? Its a 1975 CB550 four

[TwoTired]

The black box under the grey one on the right is your fuse box. Pull off the cover to find the fuses.

The brown wire over the fender is the rear tail run light. S/b connected to another brown.

You really should download the Honda Shop Manual to get a wire diagram for your bike.  Otherwise, you may as well cover your eyes while working on the bike.


If your bike was connected with revers polarity during the jump start, then the charging system and it associated wiring was put at great risk.  It is NOT fused.  And wires melt if this is done for any length of time.  Check the wires to the rectifier and pay particular attention to the green wire in the harness and it's connection point under the tank at the coil mount.

Cheers,

[MoTo-BunnY]

My CB500 had that "empty" ground wire as shown in the second picture, too (if that IS a ground wire in your picture). It was all dusty and oxidized - looked like it had NEVER been used. I just ended up using it later, when I wired in some other lighting. 

And yeah, what TT said!  (see attached picture    )

[sinister902]

im amazed at the quickness and helpfulness of posts here.....but forgive me, i havent worked on a bike like this, its my first road bike, everything else i had was a mid 90's motocrosser. What is the rectifier and where is it located? is there a way to test it?

[MoTo-BunnY]

im amazed at the quickness and helpfulness of posts here.....but forgive me, i havent worked on a bike like this, its my first road bike, everything else i had was a mid 90's motocrosser. What is the rectifier and where is it located? is there a way to test it?

Dood - download some manuals, seriously. .  .   

http://www.honda4fun.com/man_officina/man_officina.html

[sinister902]

Found the popped fuse....well, i'll have to swap this one out if i can find one locally, grab a battery, and free up the cylinders and grab plugs. fingers crossed!!!!

[MoTo-BunnY]

Just know that these fuses are a hard to find size - a bit shorter than the commonly available ones. If you use the latter, they won't make a whole lot of contact on both ends (as it will be too long) and may cause further problems.

There are a variety of older posts discussing this with fuse sources as well as many peeps opting to installing modern blade-type fuses as replacement.

[jsaab2748]

If you're in the U.S.A. I found some correct length and rated fuses at Auto Zone.