[geoffbaker]

Yes, I was able to successfully install a DATEL/murata 12v digital voltmeter in the ammeter casing of my Bullet.

I can report that it was an easy, slick mod and well worth doing for anyone who doesn't need an ammeter (electronic ignition bullets?)

I opened the case and removed the ammeter mechanism. The datel unit does require a little fiddling. The base of the voltmeter needs to be filed down a bit, and the corners require gentle filing at the top to make it fit in the rubber ring.

I took a round file and enlarged the openings at the back to make room for the two connections (you need to make sure they don't conduct across the aluminum ammeter shell).

So I filed down the bottom of the voltmeter until it was flat and the two screws protruded out of the ammeter case. Then I used two fork terminal connectors, bent to 90 degrees so they project out of the casing, and carefully used electrical tape to ensure the unit would be insulated.

I cut a rectangle of masking tape, applied it to the glass, and sprayed the glass matt black. Once dry, I removed the rectangle, giving me a window.

Then I fit everything together and have temporarily crimped the outer ring back to hold it together.

It works extremely well.

I plan on redoing the paint, as the voltmeter face is a dark blue, not black, to make it look just a little better; but in the pictures you can see the results.

I like it!



Above, the working voltmeter.



The base of the voltmeter itself, with two insulated fork terminals attached.

[Rick Sperko]

Cool.

[Chasfield]

That is a very neat little unit that you have made.

The .01 volt precision (as opposed to just having a handful of coloured LEDs, like on  Kuryakyn unit) would probably give a pretty clear indication of voltage drop due to points opening. So it might adequately replace an ammeter as a starting aid on a coil an points equipped machine.

Edit:

Spot my deliberate mistake above  - voltage will rise when points open and unload the batt.

[Rick Sperko]

That is a very neat little unit that you have made.

The .01 volt precision (as opposed to just having a handful of coloured LEDs, like on  Kuryakyn unit) would probably give a pretty clear indication of voltage drop due to points opening. So it might adequately replace an ammeter as a starting aid on a coil an points equipped machine.

That would be great. Geoff, will you please slap your gas engine back in for today to test it? You could probably keep the 44mm carb and water bottle in place.

Seriously, though if a voltmeter could register the voltage drop for kicking that would be very cool.

-Rick

[geoffbaker]

That is a very neat little unit that you have made.

The .01 volt precision (as opposed to just having a handful of coloured LEDs, like on  Kuryakyn unit) would probably give a pretty clear indication of voltage drop due to points opening. So it might adequately replace an ammeter as a starting aid on a coil an points equipped machine.

That would be great. Geoff, will you please slap your gas engine back in for today to test it? You could probably keep the 44mm carb and water bottle in place.

Seriously, though if a voltmeter could register the voltage drop for kicking that would be very cool.

-Rick

Sure, I'll do that this week

Actually, I'd recommend one of you guys get the voltmeter and see. If it doesn't show a points drop, it would still be useful, and could be installed most anywhere... it doesn't need to sit in the ammeter case, after all. It could be easily mounted on the handlebars or elsewhere; and being totally waterproof, it doesn't even need a box!

I'll get some blue paint today and finish the mod this weekend. I'm hoping to post better pix... my phone cam sucks at close distance photography

[Chasfield]

When I said voltage drop on points opening,  I actually meant voltage rise.

Batt voltage will drop when they close.

Doh!

 

[The Garbone]

Actually an of us with a Digital Volt meter can test the theory.... 

I am on the fence about buying one of these since I would prefer the look of a analog meter.  I like the old school neddles..

[geoffbaker]

Actually an of us with a Digital Volt meter can test the theory.... 

I am on the fence about buying one of these since I would prefer the look of a analog meter.  I like the old school neddles..

Me too, but couldn't find one that would fit. This is the next best thing.

If you come across a 44mm analog voltmeter let me know!

[Rick Sperko]

Actually an of us with a Digital Volt meter can test the theory.... 

I am on the fence about buying one of these since I would prefer the look of a analog meter.  I like the old school neddles..

That is what stops me too. I don't mind having a bunch of technology on my bike (LED, EI), I just don't want to see it.

-Rick

[geoffbaker]

Well the other alternative is the 48mm analog german meter. Pricey and shipping is extremely expensive...and too big.

But I would be interested to see the result if one of you went ahead and drilled out the opening in the casque and installed one...

It would look sharp!

[geoffbaker]

Here's a final picture of the installed voltmeter. I painted the back of the glass dark blue so it looks better with the display, then crimpled the chrome cover on and installed it. I cut out the BA7 bulb and holder (no longer necessary) and wired the voltmeter directly into the battery.

Ultimately, I'll install a switch; I'm trying to get a nice retro one to replace the ignition key, and all it will probalby do is turn the voltmeter off!

According to the draw of the voltmeter, it should take it about six months to run my battery down, so long as I never start the bike.. so I have some time...

[Chasfield]

I have tried out my digital multimeter (on its 0 - 20V DC setting) as a means of detecting points opening. With points closed, the battery voltage drags down to 11.9. When the points open, the voltage floats back up promptly to 12.3. My battery is only six months old so I assume these are reasonably typical numbers for a batt. in sound condition.

So, the DVM unit should be ok as a replacement for the ammeter, as far as engine starting goes.

NB, an analogue automotive voltmeter might have too much lag due to needle damping for this job. The one I had in my old car took about 15 seconds to go to zero when the ignition was turned off.

[geoffbaker]

An interesting point!

We all think analog meters are cool... but in this case an analog voltmeter might not show enough of a "flick" when the points opened...

Esp as analog meters for motorcycles in particular tend to be heavily damped... :

So it sounds as if a digital voltmeter would be as effective a tool in finding TDC as the ammeter, anyway...

At any rate, I've been riding around town and find the voltmeter is excellent for giving you an instant "view" of the electrical system. When I start it drops down under 12 on idle, but any acceleration at all takes it from12v to up to a high of about 14.5. So I know the regulator is regulating (if it rose over 15 the regulator isn't working) and the system is charging nicely. After a few minutes it tends to sit in the 13v range except at idle.

My only remaining electrical concern is the HID headlamp. These work differently than incandescent bulbs, so instead of dimming when the system is at idle, the HID lamp starts "strobing" at anything less than 12v...

I'm hoping that with the all new electrics this problem will be greatly reduced.

[The Garbone]

Ok,  this is a bit of a thread jacking but here goes.

The last few days I have been mulling the entire 44mm hole thing,  and after seeing Slumdog Millionaire this weekend I came to the conclusion this measurement was a bit odd and considering the castings were made in the UK and mostly Witworth I figured it must be a standard size.   Either 1.75" or 1.5".

Went down to the local AutoZone parts store and bought one of these 3 packs of 1.5" gauges for $30.



Took out the voltmeter and and went to work..

I jumpered the Red wires together and insulated them real good.  They are not needed for the voltmeter application.    I then attached the bulb for gauge and gauge leads in common to some fork lugs on the meter (the meter basically reads the voltage drop across the bulb).      It works great.    I put one wrap of electrical tape around the gauge and reused the factory rubber boot and replaced the gauge.. Fits real snug.



Voltage with points open...



Voltage with points closed..



It works well, with the exception that it wiggles like a $20 stripper at idle,  but once up to speed it smooths out real nice.     I imagine you could put a capacitor in parallel with it and slow down the jiggling,  but that would ruin the vintage feel...   

[geoffbaker]

Nice, garbone, very nice!

Does it flick at TDC though?

My only reservation would be that when I was searching for voltmeters analog or digital I wanted them to be designed for motorcycles - I was concerned that automobile versions would a) not be waterproof enough and b) not be damped enough.

But if it works well, that's all that matters.

And I do like old style needles...