New Maxim XJ550

Hello XJ Forum!
Recently I bought a old 82' Yamaha XJ550. Long story short, the carbs were lookin like they needed to be rebuilt since the bike kept cutting out, and the bike shop was going to charge me 1,800$ for the whole kit and caboodle. Of course I denied repairs and gladly would do it myself, honestly I was worried it was something else major. This turned into a fix it up bike very quickly.

1. Rebuilt carbs, new air filter, new oil and filter, new spark plugs, and as I discovered, it needed a fresh battery.

So I went to my local O'Reilly's, got the same model (or so I thought) battery that the front desk got me.
Took the battery home, hooked it up to my bike excited to get it started finally after everything

It made some funky noises and then I saw out of the corner of my eye a spark jump from the starter button to my gas tank (context: my starter button was dissembled at the time because the button was not working so I would ground the button with some copper wire to bypass the button). So I immediately realized I f*** up. The battery was the same model, EXCEPT the polarities were switched (feel free to give me crap honestly, dumb mistake)! I was so upset, went back to the store, traded in the battery and tried everything. Luckily the Neutral light would turn on but nothing, no noise, nada.

I've tried replacing the Diodes, a few relays, and now the bike is turning into a money pit...

If anyone could give me any advice, PLEASE, I'll take anything.

Also I recently discovered this forum, so hopefully I am posting this in the right place, so take it easy on me!

 

Oh man a reverse polarity can really do some damage. Things like the alternator regulator/diode block, TCI module and any electronic instrumentation will most likely be destroyed. I'm trying to take it easy but the reality is this is going to get expensive. The starter motor is a perminant magnet design and will run in reverse connected backwards but the starter drive clutch won't engage giving you some strange noises, no damage done there.

At the very least you're looking at possibly replacing the TCI (ignition module) and the alternator regulator/diode block. As for the sparks jumping from the starter button I can't help you other than suggesting to go with the correct parts and eliminate the unknown variables.

In time it is repairable, just be patient and get the factory (not Clymer or other aftermarket) service manual for the bike. Read it, study it and take things one step at a time.

 

You didn't mention checking the fuses after the reversal.

It should just blow the main fuse as the diodes in the Rect/Reg become forward biased. If you didn't turn the key on with the battery reversed then none of the electronics other than possibly the Rect/Reg should be damaged.

 

As I understand from reading the post there was an attempt to start the bike with the reversed polarity battery, if the IGN was off there might be some hope but even if the main fuse popped for the reg at greater than 10 amps I'd say it too popped. After almost 25 years with Motorola one thing I've learned is expect the worst.

 

And it could be, but let's hope someone got lucky

 

A little luck wouldn't hurt