Tach Failure

[samdroid]

3 hours ago, gstallons said:

I checked my Greenie just while ago .  At pin 3 (yellow/black stripe) I got 50hz at idle . At 3k I measured around 150hz.  

 HTH . Sorry for the delay .

Thank you! Did you happen to test DC voltage?

[gstallons]

At the yellow/black wire ? No , frequency only . You would get DC if this were a square wave (pulse width modulation) signal to the tach . IDT this was this the case w/this setup .  

Or , no I didn't check the alternator output voltage . I can check both of these if I need to .                               

[cowtownchemist]

 

Hi everyone, I have recently acquired a 2000 V11 sport and it has they typical bouncy speedometer and non-working tachometer as many of these Veglia Borletti gauges do.  I’ve spent many hours reading the many threads on this topic here in the forum and on other forums as well.  This research has led me to the decision to replace the Veglias with the Speedhuts.

HOWEVER, since I have made that decision, I figured I have nothing to lose by attempting a repair on the instruments and documenting what I find.  Also adding some pictures along the way for anyone else who may want to attempt this in the future.  Since the speedometer kind of works I went in on the tach first. 

These are the threads that I found most useful:

2004 https://www.v11lemans.com/forums/topic/3282-another-tach-failure/

2007 https://www.v11lemans.com/forums/topic/12441-open-up-your-veglia-and-close-it-back-again/

Step 1:  I played ‘round robin’ with the relays to rule out a faulty relay.  I cleaned the relay contact points with Deoxit as I went.  Nothing changed.

Step 2:  I opened up the instruments housing and tested the signals with a multimeter.  I displayed a 12V on the red/black power line.  I displayed an increase in frequency while turning the throttle on the yellow/black line.  This tells me that the electronics are fine and that the issue is mechanical within the tachometer.

Step 3:  I removed the tachometer from the dash by removing the three spade connections and by snipping the little black ground wire for the light bulb.

I have the early white faced version with a date stamp of Jan. 19, 2000.

   

Step 4: I removed the bezel by prying it up using one of those little screwdrivers which are pre-bent.  After about 10 minutes of this I had to wrap the screwdriver with some tape as it was really hurting my hand.  After about 10 more minutes I was really wishing I had just cut the unit in half like so many others did but I was already in it so I pushed on.  After about a total of 30 minutes of prying I finally had the bezel off!

 

Continued in next post...

 

[cowtownchemist]

As I was prying a small piece of the counter weight fell out of the unit.  Problem #1 identified.  Upon removing the mechanism from the housing I had the second full counterweight fall out.  Problem #2 identified. 

 

Upon close inspection of the contact wires which many have said that they have found detached I see one is attached and the second appears broken.  Problem #3 possibly identified.  It is not clear to me exactly where to re-solder this second wire to.  Searching the forum I read that a few have done this and posted pictures of it but those picture links don’t work anymore.

My next planned step is to put the counter weights back together with a little drop of superglue and test the tach without attempting a re-solder and see what happens.  I don’t think this will work but I will try anyways. 

My question to you who have done this repair before, do I need to re-solder that second wire to something and if yes, to where?

[cowtownchemist]

So I glued in the counterweights and tested.  As expected still no signs of life. 

I looked closely at the wires down below and it appeared that the unattached wired on the post is just the remnant of broken copper wire coming off of the spool.  I looked at the spool and saw what looked like a loose wire in there so I fished out and wrapped it around the post and soldered it on.  It is not a pretty soldering job, but it was a tiny little space in there and the magnet kept pulling the soldering iron to it. 

The spring was a pain to deal with as it kept getting all twisted so in the end I ended up de-soldering it to straighten it out and the soldered back in place.  It is still a little wonky compared to how it started but seems to work.

I hooked the tach back up to the bike for a test…still no signs of life…

[samdroid]

Check voltage regulator, main fuse and relays. Also check all your grounds. My tach died by the same method, wires detached from posts with some burning around the solder joints. I don't have the hands of a surgeon and my resoldering attempts were unsuccessful.

A bad ground likely fried my Voltage Regulator. I was returning from a long ride when the tach died, when I got home and pulled the seat I had 18 volts across the battery terminals and a melted 30A fuse! Fortunately I didn't incur any other electrical damage and my ecu survived.

Grounding issues are now fixed, voltage in check and I'm getting the 'right' frequency off the tach wire but haven't put a replacement tach in to confirm. 

Good luck!

[docc]

On 5/19/2023 at 10:25 AM, samdroid said:

Check voltage regulator, main fuse and relays. Also check all your grounds. My tach died by the same method, wires detached from posts with some burning around the solder joints. I don't have the hands of a surgeon and my resoldering attempts were unsuccessful.

A bad ground likely fried my Voltage Regulator. I was returning from a long ride when the tach died, when I got home and pulled the seat I had 18 volts across the battery terminals and a melted 30A fuse! Fortunately I didn't incur any other electrical damage and my ecu survived.

Grounding issues are now fixed, voltage in check and I'm getting the 'right' frequency off the tach wire but haven't put a replacement tach in to confirm. 

Good luck!

With an over-voltage failure like that, watch your relays for signs of damage and malfunction . . .

[cowtownchemist]

I repainted the tach needle with some orange acrylic paint and sealed the tach back up using a clamp to hold it down and lightly tapping all around the bezel with the rounded side of a ball peen hammer.  Went to reinstall it on the bike only to notice I put the face plate on upside down...  So I opened it back up again, rearranged the face plate to the correct way and sealed up it a second time... 

I replaced all of the relays for preventative maintenance.  I'm not sure how to check the proper function of the voltage regulator, but I did confirm that the 30amp fuse looks good with no signs of overheating and that I am getting the expected signals through the tach wires.  At this point I am officially giving up on getting the tach working and will continue with my original plan of ordering Speedhut replacements.

On the positive side, I played with the routing of the speedometer cable and noticed a significant reduction in the amount of needle wobble.  Its still not exactly stable, but definitely allows me to make a better estimate of how fast I am going!

[samdroid]

2 hours ago, cowtownchemist said:

I repainted the tach needle with some orange acrylic paint and sealed the tach back up using a clamp to hold it down and lightly tapping all around the bezel with the rounded side of a ball peen hammer.  Went to reinstall it on the bike only to notice I put the face plate on upside down...  So I opened it back up again, rearranged the face plate to the correct way and sealed up it a second time... 

I replaced all of the relays for preventative maintenance.  I'm not sure how to check the proper function of the voltage regulator, but I did confirm that the 30amp fuse looks good with no signs of overheating and that I am getting the expected signals through the tach wires.  At this point I am officially giving up on getting the tach working and will continue with my original plan of ordering Speedhut replacements.

On the positive side, I played with the routing of the speedometer cable and noticed a significant reduction in the amount of needle wobble.  Its still not exactly stable, but definitely allows me to make a better estimate of how fast I am going!

Voltage shouldn't exceed ~14.5 at any rpm. You can test at the battery terminal with the bike running. Idle voltage will be 12.9+ rev the bike. If you see 15+ as the revs climb , shut er down and don't run it until regulator is replaced. Worth confirming regardless which route you go with replacement instruments 

[p6x]

@cowtownchemist

Would a QUOTA ES Tachometer work for you?

Check this out on ebay.it. There are other QUOTA tachometers for sale too.

https://www.ebay.it/itm/385292189872

[cowtownchemist]

Thanks Samdroid, I will double check voltages at the battery later tonight to confirm.  P6x, that Quota ES tach does look identical, but for that price I'd rather go for the modern Speedhut version.

[p6x]

58 minutes ago, cowtownchemist said:

Thanks Samdroid, I will double check voltages at the battery later tonight to confirm.  P6x, that Quota ES tach does look identical, but for that price I'd rather go for the modern Speedhut version.

There is the "make an offer" button enabled, you may be able to get it for less, but probably not less enough to make it a better alternative. This was just in case you wanted to keep your V11 as before.

[cowtownchemist]

I thought a lot about retaining the original look to the gauges.  But my V11 already has a number of customizations and I know I will never sell it as a show piece.  So I'm just going to go ahead and make it mine.  Since the bike is black with the red frame and porkchops, I'm actually thinking of using this color scheme with the Guzzi eagle printed in there