Power problems - Alternator changed....now what to look at???

[Nico]

Have been having power issues. Here is what I have done so far and where I stand...

New Battery over the winter

Bike was not holding power well, but made it to Ohio and back. Then wouldn't start without a jump. Finally, last weekend I took the bike out and it died within a mile. No juice at all.

So, I removed the alternator and got a MARS rebuilt. I installed the rebuilt tonight, and after sewing it all back up, the bike STILL wouldn't start without a jump. I had the battery on the charger for a few days and the charger read that the battery was charged, but after installing it, there was still not enough juice to start the bike without a jump.

I jumped the bike, it started and I left it running to charge the battery. I was going to take it out for a ride to charge the battery even more, but by the time I got changed into my riding clothes, the bike started to idle poorly. So I shut the bike off, and when I tried to start it again, nothing! Not enough power to even turn over the engine.

What would you look for? I cleaned the ground wire at the block connection and at the negative terminal. I checked all the fuses and none appear to be blown....

Any insight is appreciated.

[spongebob]

Mmmmmmmm..... ok lets start here...... battery cranks bike..... alt. then supplies power to charge battery AND to supply power to bike to run, lights, etc...... Need a volt meter.... a proper charged battery is about 13.2 volts with NO load.... avgs out to 2.2 volts per cell...... alt. should be charging back to battery above this 13.2 volts...... then  after checking this, might have to check amp draw of battery when bike turned OFF..... to see if a drain is on battery after bike is cut off......

[Gryphon Rider]

Be sure to write down your observations during the following steps:
1. Fully charge your battery again.
2. Wait a couple of hours and then put a voltmeter on the battery. It should read 12.9 volts or very near that. If not, you have a battery problem.
3. Assuming the battery has 12.9 volts, install it in the bike, then start the bike, even if you have to jump start it.
4. With the engine above 1500 RPM, check the voltage at the battery terminals. It should read 13.8-14.3 volts if the alternator is working and the charging system wiring and connections are good. If it reads below 13V, you definitely have a charging system problem.
5. Assuming everything checks out, go for a half-hour highway ride, followed by someone with jumper cables.
6. Stop for coffee but leave the bike running. With a spare key, remove the seat and check the voltage at 1500 RPM. Assuming you get the 13.8-14.3V, the charging system is good. Shut off the bike and go buy your coffee.
7. Coffee finished, try starting the bike. If it easily starts, consider it all good. If not, take your battery back to the seller, show him your notes, and ask for replacement under warranty.

[pancho]

Nico, you are changing parts without ever verifying weather they are good or bad...  You need to pin this down. Check your charging system as has been suggested..... if it is good, take the battery and do a load test.....  if it is good, you starter bearings may be binding up.       There are only a few parts here to work with, but you need to know the condition of each.

[xman]

Battery's kill alternators and alternators kill battery's.  Of course each dies from natural causes. As you said you need to jump it. So the battery has no capacity. Battery is a problem. New battery could have been killed by a overcharging alternator.  When it runs >1500 RPM there should be 14.2 volts charging the battery, then the alternator is good. If you don't have a digital volt meter, get the cheapest one they sell at any auto parts store. They are precisely accurate.   

[Michvalk]

The Alt won't charge the battery with the bike Idleing. It takes 1500 RPM's or above to start charging. At idle the bike uses more power than the alt puts out. Also, the bike won't start without the full output power of the battery, hense the need to jumpstart. You need a new battery, or at least a complete charge on the old one. Just because you replaced the battery a few months ago, doesn't mean it's not bad. After you charge it up (don't count on the alt to do this job) with a charger, try it again.  

[Toledo Mark]

Nico, you are changing parts without ever verifying weather they are good or bad...  You need to pin this down. Check your charging system as has been suggested..... if it is good, take the battery and do a load test.....  if it is good, you starter bearings may be binding up.       There are only a few parts here to work with, but you need to know the condition of each.

What are starter bearings?

[fudgie]

battery is my guess.