Cali tank issue

[TejasNW]

I removed the tank on my (new to me) '99 Cali but found a problem.  This wire is damaged, and I have no idea what the part is or does.  It is the long black stem that bolts to the nipple on the tank just forward of the petcock.  It sits vertically up into the left side of the tank.  I assume it is a gauge sensor for full level.  The wire has been damaged near the connector and was unplugged when I removed the tank.  I could not find where it reconnects.

Can someone tell me what this part is, and where it connects?  I would like to replace it but may have to repair if not available.  I have downloaded the service manual of the 'net and will start digging through it, but thought someone would recognize it.

[guzzisteve]

Yes, tank level. Plugs into harness w/female socket of like. The lead w/no red stripe.

[F-Fred]

MG Cycle has it for $30 Edit: MG doesn't seem to list one for post-1997 models.

[OldMojo]

Yep, it's the sensor for the low fuel light. Never were particularly reliable. The MG Cycle part appears to be of a different design, so perhaps it will work better.

Presumably when you removed the tank you disconnected the electric petcock harness. The missing fuel sensor connection should share a bundle with it, so follow it back. If I remember correctly, the fuel light and petcock connectors are identical, so take care not to get them mixed up when putting everything back together.

[Kiwi_Roy]

Yep, it's the sensor for the low fuel light. Never were particularly reliable. The MG Cycle part appears to be of a different design, so perhaps it will work better.

Presumably when you removed the tank you disconnected the electric petcock harness. The missing fuel sensor connection should share a bundle with it, so follow it back. If I remember correctly, the fuel light and petcock connectors are identical, so take care not to get them mixed up when putting everything back together.

As he says take care not to mix the two or you can burn out the sensor if you get it mixed with the Electric Petcock
Is it possible to re-attach the wires, a new sensor is quite expensive.
The sensor is a thermistor, it will measure between 1 & 2 Ohms check for that with a multimeter, if so it's probably ok
When it becomes uncovered it starts to warm up which brings the resistance down resulting in faster heating and less resistance untie eventually it turns the fuel light ON
I always had good results with these if it wasn't already burnt out.
BTW plugging it into the petcock connector won't do any damage if there is lots of fuel in the tank but if the tank is empty it will become white hot and self destruct in seconds, this won't set fire to the fuel because its contained within a tiny metal capsule that cools the flame.

[Rich A]

MG Cycle has it for $30

https://www.mgcycle.com/index.php?main_page=product_info&cPath=382&products_id=1171

This sensor is for an earlier Cal. The newer ones are much more expensive. Harper's had them at one point.

Rich

[Kiwi_Roy]

This sensor is for an earlier Cal. The newer ones are much more expensive. Harper's had them at one point.

Rich

Ok the one you show is not a thermistor, its a reed switch but the same applies if you get it on the wrong supply the contacts will weld together.
Its dead easy to check, multimeter on Ohms connected to the wires, then move the float up and down, should go from open circuit to zero Ohms at simulated low level.
It should be possible to replace the reed switch.

[ejs]

The 1999 EV has a termistor as a level indikator. Submerged in gas the termistor has an resistance about 600 ohm, therefore the lamp is off...
At low level the termistor is above gas level and heats up enough to get low resistance so level indikator lamp lit up. Circuit is then in balanse.
So measure between the 2 wires from level indicator.
Some hundered ohms = ok. Zero or infinite ohms = bad

[F-Fred]

This sensor is for an earlier Cal. The newer ones are much more expensive. Harper's had them at one point.

Rich

You are correct.  My bad.  They don't list one currently for post-1997 Calis.

[Antietam Classic Cycle]

https://www.af1racing.com/OEM-Moto-Guzzi-Fuel-Sender-GU03103000

[TejasNW]

Excellent information, all.  Thank you for your help and replies.  I am not able to get the nut back on the nipple of the tank.  The threads seem to be okay, except for the top or entrance thread.  I can get the nut to catch and make about an 1/8th turn before it pops off.  Any tricks to get the threads on a fine pitch to catch?  I am taking the tank to a machinist whom works on tanks for an opinion, but really don't want to have to chop up this tank to repair the nipple if at all possible. 

The tank has the manual petcock fortunately.  I also found the two connectors mentioned and the red band, so will keep them straight.  Not sure if the fuel level sending unit is all that important.  My '03 quit working early on (internal pump) and I just learned to live with it after it failed a second time.  I just need the big hole in the bottom of the tank sealed at this point.  I am assuming the threads on the nipple are metric making them the british standard pipe thread?  If I have to cut and replace the nipple i will likely just have him cap the nipple; but would be helpful if we could use a brass cap on a repaired thread.

Just thinking out loud.  I appreciate everyone's responses and information.  Thank you.

[guzzisteve]

Don't forget one half of the locknut is left handed thread, the other 1/2 is regular let's say.

May be same nut used on petcocks if you have one laying around.

[TejasNW]

Thank you, Charlie for finding that part!  Many Thanks.  I could not find the correct part for my year on sites I found.

Just heard from the machinist.  Tank threads are not damaged.  He chased the threads and found them to be good.  I have the part on order and will be able to get things back together when I get back to town.  Very happy for that; and thankful to all for the support and information.

Ride safely, all.

[Rich A]

One more thing--the wire running to that sensor has a tendency to break right where it goes into the sensor. It's a good idea to put some sort of strain relief on so that the wire doesn't flex there. You might put a blob of sillycone on the sensor and cable tie the wire so it doesn't move.

Rich A