I did a dumb thing...

[psyverson]

... how bad off am I?

I have a 1968 ca77. She wants to start. She really does. Battery needs replacing, but
my roommate and I almost got it going with a few push/run starts around the block.

However, I have the bright idea to try the electric start by jumping the battery from
my truck. Truck was off, I just used the battery and a pair of cables.

The ignition worked and she tried in vain to roar to life, kind of a growl and a shake
but no spark. Tried the trick with the plugs out and placed on the engine body to see if I could get a spark.. no spark. Damn. So I stopped and unhooked the battery.

Awhile later, no telling how long a few hours maybe, my roommate is outside and hears from the bike
a loud POP, like a gunshot (I live in New Orleans so they truly thought it was a gunshot).

Now when I hook it up to the truck and try the ignition, I get nothing.

Did I fry just the battery, which I wanted to replace anyway, or did I fry the whole bike?

Please help..

Thanks,

Pete
NOLA

[Hotshoe]

Pete,
Great to finally see someone else from New Orleans posting, I live in Mid City.
I have some experience trouble shooting 305's and might be able to help.
PM me and maybe we can meet up after Mardi Gras if you haven't fixed it yourself by then.
Sounds like you at least have ignition problems and should probably start with the new battery you mentioned.
Regards, Chuck

[hillhudson]

bill silver says in his book that trying to start and run a bike with a dead battery will end up running off of the AC charging system and will blow all of your lights.

[mike1969]

First thing to check would be the main fuse.

[psyverson]

I'll take off the battery and replace it and see if I can find a main fuse.

-Pete

[mike1969]

The main fuse should be in a black fuse holder near the positive post of the battery.

[Snakeoil]

If you left the cables connected while it sat there, the positive cable might have slowly moved due to the weight of the cables and shorted to the frame. This should have resulted in a burn mark somewhere. It could have drawn an arc that that could have been the pop you heard.

Your truck battery will simply provide the amps that the bike battery is asking for. However, if you bike battery is very old and there is a short between the plates, that pop might have been the truck battery blowing out that short. I would have expected a sign of that on the battery case though. Might even expect acid out the vent or blown a few of the caps off. You might want to check for an acid leak.

Cannot understand why the fuse would blow with the bike just sitting there unless you left the ignition on and there is a high resistance short somewhere that finally killed the fuse. The alternator should not make enough current to blow that fuse when the bike is being cranked.

And just for terminology sake, if you have no spark, the ignition is NOT working properly. I suspect you are calling the starting circuit for the electric start, the ignition. That is NOT the ignition. It's the starter. If you had no spark to begin with while the truck battery was connected, no amount of cranking will make it produce a spark.

Any chance that the pop you heard was unburned fuel igniting in the muffler after so much cranking? Not sure why it would ignite by itself, but a gunshot sounds more like a backfire to me than a fuse popping.

regards,
Rob