you said the battery is reading 12.9V. I assume you are checking it at the battery. Then you said you hit the start button and the voltage drops to 8.9V. This means that a heavy load is being put on the battery (starter) and the battery is dropping off hard. 8.9V will not turn the starter. My point is, if something is dropping the battery to that level then obviously your components are working fine but either way that battery is toast. Not to say there isn't something else wrong but no way it should drop that low and, even though it is probably just the battery, you will never find any other problem until it is replaced.

 

A loose ground connection in a DC system can cause such a voltage drop as the loose connection is seen as resistance. Check all connections before you replace anything.

 

Hard to tell the steps you took. Sounds like a few times you read voltage drop at battery when trying to turn over. Then later sounds like you read 0 voltage drop while trying to turn over.

Since most small part stores offer free battery testing if I was you I would remove it and have it tested.
If indeed you have 0 volt drop at battery when trying to turn it over grounds are a good start to check. Then on to relays/switches etc. Good luck.

 

just so I'm not perceived as in idiot here......I did say check the voltage at the battery. If you are checking it at the battery there cannot be a voltage drop, and if the voltage at the battery went from 12.9 to 8.9 the battery is bad, no question. So to the OP....when you measured the volts as you posted first, were they measured at the battery or at another point in the system?

 

Quote:

Originally Posted by 79lowrider

okay so tell me is it possible this could be caused by the system relay?

Yes it most certainly is possible, I had darn near the same exact things happening to my 06 streetbob for about two weeks, I tracked it down to two things, the first was my fault partially, when I was relocating my turn sigs to the forks, I jostled around the ignition switch 3 terminal plug and obviously just had it barely cocked so that the right vibration of movement and bam the bike shut down, but when this happened I lost everything, headlight, gauges, starter, horn, everything. I fixed that sucker but good, I took the whole ignition switch out an zip tied it twice around the switch, that connector melt on there in a fire before it vibrates or comes off again.
Thought I had it fixed, coincidentally, had similiar results after riding out to the Lone Star Ralley, my bike shut down a number of times, but I had a headlight, and it would crank, but I was getting intermittant fuel gauge readings, true and then zero, and back to true, etc, sometimes the fuel pump would kick in and sometimes it wouldn't. After another week and a half trouble shooting, thinking it's heat related or something, I find out it's my system realy, replaced it for 6 maybe 7 bucks from dealer, never had a problem since. I now carry a spare starter and fuse relay in my kit.....
As for my battery since the ignition switch was involved, in the beginning, I put a meter on it while trying to crank but no voltage drop, well at the time that made absolutely no since, but afterwords, it does because the ignition switch wouldn't kick the solenoid to engage the starter. So I finally took the battery to auto zone, they threw it on a load test, it was kicking tail, which at the time was disgusting to hear, since that meant back to the drawing board.

 

yep ... take a good look at it.... just in case.

 

Hi.... From my small knoledge... Charge your battery... check fuse box maybe some dirt and not conecting properly !!! also the Ignition maybe a small wire is ready to comeout.... take it step by step starting with the ignition.....and battery !!! I had a similar problem last night and the HD brothers helped me out !!!! good luck my Brother.. I know how you feel

 

alright guys well lol it was the battery i guess it had a fused cell in it?? never heard of that but i guess it does happen lol showed good but soon as any load was applied it would drop to 8.0 and a few times dropped to 1.9 but within a few seconds it would come right back up to 12.8-12.9 lol crazy anyways want to thank you all again
Paul

 

glad it is fixed!