Author Topic: 1954GF speedo drive  (Read 1151 times)

Offline victortrry

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1954GF speedo drive
« on: 01.06. 2014 08:35 »
What is going to happen when I replace the sidecar rear sprocket with a solo sprocket.
Do I also need to replace the speedo drive in the gearbox?

Victor

Offline bsa-bill

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Re: 1954GF speedo drive
« Reply #1 on: 01.06. 2014 09:01 »
No
But it a good point that's ignored by most (shouldn't have said that)
I assume BSA made them as singles so are geared as singles and a sidecar would be an addition by the owner who would change the sprocket, I've never seen or heard of a sidecar speedo (but I'm no wikipedea)
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline duTch

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Re: 1954GF speedo drive
« Reply #2 on: 01.06. 2014 09:22 »

 Vic, It'd be easy for me to say something along the lines of ' how'd you get a sprocket on the sidecar. ?' but I won't....... *conf*
   So what exactly are you doing....? Are you removing the sidecar and going solo..as the wording otherwise suggests.?
   If so you shouldn't need to do anything as if you replace with a standard gearing sprocket, the speedo should be calibrated accordingly.
  If adding a sidecar, then you'll just need to do some mathematics and note the difference in ratios and calculate the speed (also) accordingly..!
 In this case, you could do what I did and add a bicycle speedo and calibrate it however you want...!

Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
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Online Brian

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Re: 1954GF speedo drive
« Reply #3 on: 01.06. 2014 10:01 »
Here you go Bill, a listing of speedo's including the correct ones for sidecar use.

Online Greybeard

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Re: 1954GF speedo drive
« Reply #4 on: 01.06. 2014 10:20 »
I wanted to check my speedo for accuracy. I found a free App for my mobile, (7" tablet) device that shows speed using GPS location. I've read that this is an accurate system, but only on flat ground; the system cannot calculate gradients. I bungied the tablet to the top of the petrol tank and went for a ride. I discovered that my BSA speedo is more accurate than my modern car which over reads about 10%.

Offline bsa-bill

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Re: 1954GF speedo drive
« Reply #5 on: 01.06. 2014 11:15 »
Nice one Brian

Sometimes you just know when your typing there's a doubt

Lots of us making for the shed at this moment to check *wink2*
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline muskrat

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Re: 1954GF speedo drive
« Reply #6 on: 01.06. 2014 11:20 »
Speedo's always seem to read fast. I thought I was Doing 180KPH but the speeding ticket only said 169 *eek*. *problem*
Get a mate in a modern car to sit on 60, follow him in 4th and note your reading.
Cheers
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Offline bsa-bill

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Re: 1954GF speedo drive
« Reply #7 on: 01.06. 2014 11:39 »
Quote
I thought I was Doing 180KPH but the speeding ticket only said 169 *eek*

 *smile*
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline duTch

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Re: 1954GF speedo drive
« Reply #8 on: 01.06. 2014 12:11 »

   
Quote
Get a mate in a modern car to sit on 60, follow him in 4th and note your reading.

 ..but....?
...
Quote
Speedo's always seem to read fast.
  ?


    *smile*
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Online trevinoz

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Re: 1954GF speedo drive
« Reply #9 on: 01.06. 2014 22:29 »
Victor,
            With a bit of luck the speedo ratio will be printed on the face. Solo should be 1450, or thereabouts.

Trev.

Offline wilko

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Re: 1954GF speedo drive
« Reply #10 on: 02.06. 2014 01:02 »
If your speedo reads fast take a weight or two off your balancer wheel in your speedos guts. If It's slow add some weights.

Offline victortrry

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Re: 1954GF speedo drive
« Reply #11 on: 02.06. 2014 07:37 »
Dutch
 I am changing from 49 .tooth sprocket to a solo 42 tooth.

Victor

Offline duTch

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Re: 1954GF speedo drive
« Reply #12 on: 02.06. 2014 09:27 »

 Thanks Vic- that's what I have(standard), sometimes feels like it could use a bit longer legs, but only possible with bigger G/box sprocket, but that may be a bit too much.?

 My speedo is not the right one, is a 3305/22 - 1620, and reads about 10%slow (~89 instead of 100). As Trev (I think) said you need a 1450? 1490 rings a bell too, but someone who has the right one will know.
 Tyre profile/rim dia. will also make a difference, you'll just need to do a rolling diameter(circumference) check, and some mathematics if yer keen enough *smiley4*
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia