I found this excerpt from a thread on the old forum using Google's cached capability.
10-30-2009, 4:54 PM
PG's solenoid arrived today.
First, the new solenoid was inspected to see how it was connected internally and how that compared with the stock solenoid. They are connected identically, although the Motor and Battery posts are swapped in position. In this photo, the new solenoid is on the left and one from a 1983 GL650 is on the right.
Two of the four connector tabs on the new solenoid are not visible because the fuse is blocking their view. The battery cable is still attached on the GL650 solenoid.
An ohmmeter check confirmed they were wired the same. Both coils measured about 3 ohms. A 12 volt bench power supply was then used to activate each solenoid. A click was heard when the contacts closed. Both coils drew about the same current.
Since everything was looking good so far, the next thing was to try it out on a bike. The naked 1981 GL500 was easiest to get to so it was used.
This is when things started to get aggravating. The starter cable was not long enough to allow the solenoid to mount in place. Maybe the terminal lug could have been bent and it might have fit, but since this was just for a temporary test I chose not to do so. Note this likely would not have been an issue if the Battery and Motor post locations had not been swapped in the new solenoid.
This photo shows the next installation issue. If the cable connector housing is not modified by removing the retention/keying material it will interfere with the fuse. (The fuse is not installed in this photo.) If this were truly a plug-in replacement it should not be necessary to modify the cable housing. The connector's keying function prevents the connector from being plugged in backwards. It also helps to keep the connector from coming loose due to vibration. Again, I chose not to make any modifications for testing.
The fuse was held in place across its contact terminals from underneath for testing.
Testing went well. The bike was started many times with no problems.
I believe the diode and wiring may have smoked on PG's bike when the connector was plugged in backwards. The wiring diagram indicates the short circuit path in that case is through the diode. The main fuse should have blown, but it may not have been fast enough to protect the diode and comparatively light gauge wiring.
Swapping the Battery and Motor cables would not have caused any damage.
The solenoid will be mailed back to PG within the next few days.
In summary, this particular replacement solenoid looks like a good idea although the implementation certainly has room for improvement.