Laverda 500 Rev Counter Drive Gear

S

sport53

Junior member
Location
NE Scotland
Hi, I have an Alpino engine rebuilt to Montjuic spec that I need to order a Rev Counter Drive Gear for. Apparently there is a difference between the Alpino and Montjuic drive gears.

Does anyone know the difference between the Montjuic Rev Counter Drive Gear 41112183 and the Alpino Rev Counter Drive Gear 41112182. This is the gear installed on the end of the inlet camshaft.

Thanks
 
The counter drive only needs to be modified if the Veglia Competizione rev counter as used on the Formula models is fitted. If the stock ND clock is installed there is no need to change the drive.

In the case of a swap, BOTH gears would need to be exchanged, not only the drive worm gear on the cam.

piet
 
sfcpiet said:
The counter drive only needs to be modified if the Veglia Competizione rev counter as used on the Formula models is fitted. If the stock ND clock is installed there is no need to change the drive.

In the case of a swap, BOTH gears would need to be exchanged, not only the drive worm gear on the cam.

piet
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Thanks Piet, I do intend to utilise a Veglia Competizione rev counter, however, the rev counter has a 3/1 ratio. So I was thinking the standard drive gear would be correct?

Do you know if my assumption is correct?
 
sport53 said:
Thanks Piet, I do intend to utilise a Veglia Competizione rev counter, however, the rev counter has a 3/1 ratio. So I was thinking the standard drive gear would be correct?

Do you know if my assumption is correct?
Click to expand...
I should qualify my last post, it’s actually a Borletti Replica of the Veglia Competizione rev counter with a 3/1 ratio.
 
The original Veglia were 5:1 ratio iIrc, necessitating a drive change from the stock 3:1. All twins and triples have 3:1 ratio rev counters, Smiths and Nippon Denso. If your clone is 3:1, it should be just fine with the stock drive.

piet
 
sfcpiet said:
The original Veglia were 5:1 ratio iIrc, necessitating a drive change from the stock 3:1. All twins and triples have 3:1 ratio rev counters, Smiths and Nippon Denso. If your clone is 3:1, it should be just fine with the stock drive.

piet
Click to expand...
Thanks again Piet, I do not know for certain what driven gear I have installed in my cam cover. As this was originally an Alpino engine I would think it’s the standard driven gear, but I would like to confirm before I order the drive gear. It’s probably a tooth count difference between the F500 driven gear and the standard Alpino driven gear.
Do you know the driven gear tooth count difference between the driven gear options?
 
Hi, if you look at both gears end on as per the photo, then the tooth count is 9 & 6 for Alpino & Monty.
Tooth count for F500 is 10 & 5.
 

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F500fan said:
Hi, if you look at both gears end on as per the photo, then the tooth count is 9 & 6 for Alpino & Monty.
Tooth count for F500 is 10 & 5.
Click to expand...
That would make the original Formula 500 Competizione tach 4:1! I recall them having 5:1, mainly on bevel Ducatis.

piet
 
sfcpiet said:
That would make the original Formula 500 Competizione tach 4:1! I recall them having 5:1, mainly on bevel Ducatis.

piet
Click to expand...
Yes, 4:1 is correct. I have both the 3:1 & 4:1 sets of gears here in front of me !
But yes, you are correct on the Alpino & Montjuic bikes fitted with Nippon Denso clocks being 3:1.
My 1978 F500 was definitely fitted with an original Veglia 4:1 tacho.
 
I have a NOS Veglia Competizione, been sitting in it's box for 40 years. Wanted to fit it to my SFC way back then. Pretty sure it's 4/1.
Is there anything available that can change ratio somehow inline? Otherwise I may as well sell it. I believe they're worth a fortune these days.
 
motoddrob said:
I have a NOS Veglia Competizione, been sitting in it's box for 40 years. Wanted to fit it to my SFC way back then. Pretty sure it's 4/1.
Is there anything available that can change ratio somehow inline? Otherwise I may as well sell it. I believe they're worth a fortune these days.
Click to expand...
Rob,

You can "tune" it a bit. I modded mine to work on my 3C by adjusting the tension of the clockwork spring while driving it off my lathe at 2000rpm. The tach is now accurate at exactly 6000rpm, a bit off above and below. I can live with that...

piet
 
motoddrob said:
I have a NOS Veglia Competizione, been sitting in it's box for 40 years. Wanted to fit it to my SFC way back then. Pretty sure it's 4/1.
Is there anything available that can change ratio somehow inline? Otherwise I may as well sell it. I believe they're worth a fortune these days.
Click to expand...
Hi, there is a company here in the UK that does rev counter re-calibration for all make of instruments including Veglia. They may be of help to you.

Revcounter Conversion | Revcounter Calibration

Classic Car Spares and Engineering can reoair, recalibrate and convert your classic car revcounter to work with Points, Electronic or ECU controlled ignition systems.
classicsparesengineering.co.uk classicsparesengineering.co.uk

It might be worth just doing a Google search for revcounter conversion & calibration in Aus & see who you can find ??
 
sfcpiet said:
The original Veglia were 5:1 ratio iIrc, necessitating a drive change from the stock 3:1. All twins and triples have 3:1 ratio rev counters, Smiths and Nippon Denso. If your clone is 3:1, it should be just fine with the stock drive.

piet
Click to expand...
Hi Piet, here's a section of a post from you on July 24, 2013. I know it's a while ago now, but you were right the 1st time !!

The rev counter worm drive gear on the cam can be changed, so it really depends on what you have fitted. The standard set-up is a quite unique 3:1 ratio, so you're stuck with stock instruments, either early Smiths (off the early 750s, not much better than Vaguelias!) or the 500 road-going ND type. The Formula 500s were fitted with Veglia Competizione, 4:1 ratio iIrc. Montys usually have the ND clocks.
 
motoddrob said:
I have a NOS Veglia Competizione, been sitting in it's box for 40 years. Wanted to fit it to my SFC way back then. Pretty sure it's 4/1.
Is there anything available that can change ratio somehow inline? Otherwise I may as well sell it. I believe they're worth a fortune these days.
Click to expand...
I’ll open the bidding at a fiver...😉
 
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