Solenoid Modification 1800R
I hope I've experienced my last sticking OE solenoid. Battery was low and I tried to start my 1800R this past Saturday to take advantage of a beautiful Texas afternoon. Turned the key, all looked and sounded normal until I hit the starter switch. OE solenoid stuck and I was ready with a crescent to bang it open. That did it! I researched the forums here and headed out to grab a lawn mower solenoid recommended by one post. The Walmart website said my local store had one left. After dealing with the auto counter and being rudely informed they don't carry parts a quick 'to hell with you' I was off to Auto Zone with plan B. Another posting had talked about using a Ford solenoid and the only Ford I was completely familiar with was a '63 Falcon. Counter man was great, brought out the solenoid...I said 'OK' and $20.00 later headed home for the necessary modifications. The name and part number is Duralast F496.
The reason for this modification is because the stock Ford solenoid is grounded and when it is charged the 'I' terminal becomes hot (+12v) so that the car's ignition will allow the motor to start. The VTX corresponding terminal is -12v and the green wire connected to it is part of the safety system to kill the engine on the bike...the kick stand and clutch if I remember right. You could use the un-modified Ford solenoid, just don't connect the green wire. You'll lose the safety feature is all that will happen.
The mod involves drilling out the four rivets holding the top cover on. Use a drill bit just big enough so that you don't damage the Bakelite housing. There's a copper strap from the contactor that is connected to the 'I' terminal. You can cut this loose now or before re-assembly. Carefully remove the contactor, the spring and then un-bolt the big side terminals and the smaller front terminals marked 'S' and 'I'. Be careful unwrapping the end of the coil wire that is attached to the lug marked with the 'S', you'll be re-attaching it on re-assembly. Continue by pulling out a fiber barrier and a metal plate. Now you're down to the coil. I had to shake the solenoid a bit to get the coil started out. It is surrounded by a metal cylinder about an 1 1/2" to 2" inches tall. At this point you're after the tail end of the coil wire which is welded to the bottom of the housing. I was able to reach in with a small pair of dykes and cut this loose. You could also unwind a turn of wire and create more room. You're going to need to unwind a turn anyway to get enough to get to the 'I' terminal.
With the coil removed I took the tail end of wire and put it in some very small diameter heat shrink with enough shrink to allow the wire to pass through an insulated portion on the top of the coil (you'll see it). I ran one course of masking tape over the coil and was ready for re-assembly. Just reverse what you've taken apart. Be sure to get the '+' coil wire back onto the 'S' lug like it was before. Sand the lacquer off of the wire that is the negative end of the coil and attach that to the 'I' lug. Continue with re-assembly and use #8 screws, nuts and lock washers to get the top back on. I had to use the next size bigger drill bit to get the #8 screws to go through the body and the top cover. I used some red Locktite on the screws. I recommended testing your modified solenoid by using a 12 volt source, mine was a power supply, but a battery would work, too. Connect the negative lead to 'I' terminal and touch the positive lead to the 'S' terminal. If you've done everything right to this point you'll hear and feel it click.
At the bike you will need straighten out and drill out the large lugs with a 5/16" bit. Use a variable speed drill and GO SLOW. I split one and the other one drilled just fine after I slowed down. Bolt up the Ford solenoid. I put mine in with the lugs to the top. I've read other posts where it's installed upside down. I didn't see how that would work for me. Slide the solenoid as far forward as you can...you'll need the clearance on the right side. Bolt up the starter leads and pull the rubber boots up. The boots won't entirely cover the lugs so I wrapped electrical tape around them to avoid any unintentional contact with a ground. I cut the bullet tips off the the green and yellow wires and spliced in about 3" of 18 gauge wire to each lead and terminated them with a compression ring connector. I read a neat trick from another poster and that is to strip your wire and fold the stripped portion back onto the insulation and put that inside the ferrule of the crip connector. Seems this method will help keep the wires from breaking under vibration. It worked for me and the wire made a good connection inside the connector. The solenoid seems like it sticks out too far, but the side cover went on without any trouble. I have a connector block and a relay in this space, too (for driving lights and to provide power to the fairing). Everything went back in and is all tucked up and zip tied in place.
I put the re-charged battery in and did several start tests which were all successful. Good luck if you try this mod. I don't think you'll regret it and I'm pretty damn sure you'll never need another solenoid.