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Discussion Starter · #1 · (Edited)
OK, I've been chasing electrical gremlins since I bought my 2002 ST4S since I got it several months ago. It's coming very close to being tossed in the river with a brick tied around its neck. Anyway, I saw the post from another person that mentioned taking out the Evoluzione side stand bypass and I was going to do that and was playing around with the neutral switch that is located on the back of the transmission in a recessed hole. I tugged on it with moderate pressure and it popped off.

So my question is this, How tight should this connection be?

I can slide the connector back on the switch and can put some needle nose pliers to squeeze plastic connection around the switch but I don't know if that is adequate. If not then how do I get the switch/wire back in as a wrench won't fit down in there. Would it be worth changing out the switch entirely? If so I still don't understand how to install it with the wire on.

Heeeeelp!:mad:
 

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Volley,

That wire connector is designed to pull off the neutral switch. The end of the wire should have a brass connector protected by a short piece of clear plastic tubing. There is no tension on this wire so, as long as the brass connector is intact it should slide back on (just like a spark plug wire) and make a sound connection.

Yes you have to remove the wire first to remove the switch. Remove the right side passenger foot peg to give some swing room. You'll need a deep 14mm socket and a breaker bar with a universal joint on the end. Even w/ the U-joint you'll only get a quarter turn or so before you have to reposition your wrench. It takes patience but it can be done without special tools or removing the shock.

When you have the switch in your hands you will note that the working part is a spring loaded brass plunger that should make contact with a finger inside of the transmission. This provides a ground for the neutral light which has a constant positive current when the key is on.

Reconnect the wires, put the trans in neutral. turn on the key, and touch the plunger to the negative terminal of your battery. If your neutral light goes on, you need to replace the switch. That brass plunger wears down and gets shorter over time. If it is too short you can try using a thinner copper washer (shim). Ducati make 3 different thicknesses of shims. Try to find a dealer who stocks them. The neutral switch costs about $35.

If your neutral light does not come on when you touch the brass plunger to your negative battery terminal, check the bulb, make sure you have positive current at the bulb socket and check all connections and the continuity of all wires.

Don't be too quick to give up on your ST4s because of electrical problems. Examine all wiring modifications and additions done by the previous owner. Remove or disconnect any that are suspicious. Strip off all fairing parts and examine all wiring for fraying that could contact a grounded part. Disconnect and clean w/ contact cleaner all connectors. Reassemble with a dab of dielectric grease.

The early ST4ses were known to be delivered with a "bad batch" of ECUs. These usually present by causing hard starting when hot and/or running intermittently on one cylinder.
There are many threads on this forum that discuss this problem. It too can be solved.

Good luck.

Jeff in Colorado
 

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Discussion Starter · #3 ·
thanks for the detailed response Jeff...this is very helpful
 

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Ah,the neutral switch.I followed jeffs advice and removed the Evolucine wiring and all went well until I had to reconnect the ground wire to the switch.This wire was just stuck in the plastic connector on the back of the switch and pulled right out.The only picture I could find in parts pages showed the switch with a pigtail attached.Finally ,the connector pulled off easily and I replaced with a similar connector I found at NAPA,it clicked right on just like it was made for it!Part #784461,female connectorCheers,David
 
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