Charging system question:

[Juan1]

My '89 was having alternator issues.  After changing the coil side of the alternator, it is putting out 68-70 VAC at 5k RPM (testing between 2 wires on a multimeter), not the 75+ VAC that a perfectly healthy charging system provides.  Is this sufficient power for an all day ride?

I actually have a replacement magnetic rotor from a parts engine, but lack the !@#$!@# $40 tool to remove the rotors.  I believe that the alternator is slightly down on power because the magnets on the current rotor are 20 years old.

[beRto]

My '89 was having alternator issues.  After changing the coil side of the alternator, it is putting out 68-70 VAC at 5k RPM (testing between 2 wires on a multimeter), not the 75+ VAC that a perfectly healthy charging system provides.  Is this sufficient power for an all day ride?

I actually have a replacement magnetic rotor from a parts engine, but lack the !@#$!@# $40 tool to remove the rotors.  I believe that the alternator is slightly down on power because the magnets on the current rotor are 20 years old.

Are you referring to Alternator - Step 19 in the FAQ?
http://gstwins.com/gsboard/index.php?topic=38480.0

I measured over 80 Vac when I tested last year:
http://gstwins.com/gsboard/index.php?topic=38456.msg432285#msg432285

I don't believe the age of the magnets would affect the voltage output. Assuming the magnets are not dirty or damaged, they should still work as well as new. You should look for dirty/damaged/rusty electrical connections that may be adding resistance (and therefore "stealing" output voltage).

The confusing thing is that I'm not sure that there are electrical connection points between the alternator and your test probe location (assuming you measured at the same point as described in the FAQ). 

[Juan1]

Yep, step 19.  I'm measuring in the same spot as indicated in the pictures.  I inspected the wires, and everything seems rust-free with good insulation.

From my guitar experience I know that magnets lose some of their power as they age.  Clymer's also indicates that the rotor magnets will lose some power when they get older.  Furthermore, a quick test with a screwdriver near the magnets indicates that my '89 rotor has a bit less magnetism than the rotor from my '04 parts engine.  Whether or not this is enough to affect output voltage, I don't know. 

Honestly, the only thing keeping me from changing the rotor is the cost of Suzuki's alternator puller tool.  If the magnets aren't providing sufficient power, I'll buy the tool.  If the magnets will give another 5 years of service, I'll leave it. 

[beRto]

Yep, step 19.  I'm measuring in the same spot as indicated in the pictures.  I inspected the wires, and everything seems rust-free with good insulation.

From my guitar experience I know that magnets lose some of their power as they age.  Clymer's also indicates that the rotor magnets will lose some power when they get older.  Furthermore, a quick test with a screwdriver near the magnets indicates that my '89 rotor has a bit less magnetism than the rotor from my '04 parts engine.  Whether or not this is enough to affect output voltage, I don't know. 

Honestly, the only thing keeping me from changing the rotor is the cost of Suzuki's alternator puller tool.  If the magnets aren't providing sufficient power, I'll buy the tool.  If the magnets will give another 5 years of service, I'll leave it. 

I can't argue with empirical results! Thanks for the info. 

There's no need to buy the Suzuki tool as there are many homemade alternatives:
http://gstwins.com/gsboard/index.php?topic=42263.0
http://gstwins.com/gsboard/index.php?topic=42350.0
http://gstwins.com/gsboard/index.php?topic=6045.0
http://gstwins.com/gsboard/index.php?topic=13606.msg115554#msg115554

If you ask really nicely, someone may let you borrow theirs for the low price of return shipping (sorry, I don't have one )

[Juan1]

You are the man.  Thank you for the links!   

[beRto]

You are the man.  Thank you for the links!   

I searched for: rotor tool

 

[astroaru]

this link might help if you are as lazy as me 
http://gstwins.com/gsboard/index.php?topic=42867.0

[sledge]

My '89 was having alternator issues.  After changing the coil side of the alternator, it is putting out 68-70 VAC at 5k RPM (testing between 2 wires on a multimeter), not the 75+ VAC that a perfectly healthy charging system provides.  Is this sufficient power for an all day ride?

I actually have a replacement magnetic rotor from a parts engine, but lack the !@#$!@# $40 tool to remove the rotors.  I believe that the alternator is slightly down on power because the magnets on the current rotor are 20 years old.

Are you are still having charging problems?