Author Topic: Longstroke 1948 gearbox sprocket  (Read 548 times)

Offline Harry

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Longstroke 1948 gearbox sprocket
« on: 20.02. 2016 05:03 »
I need to replace the gearbox sprocket on the A7 Longstroke project bike. The 1948 parts book lists standard 19T as 67-3050 which is a different part number to all other bikes of that year. The parts book illustration for Longstroke sprocket seems to be drawn with a wider shoulder arising from central spline hole.  Internet searches for the precise A7 part number come up blank.  No shop I've contacted recongises the 1948 sprocket number. So my question is does the 1948 A7 sprocket differ at all from M & B series of that same era/year? Plenty of B & M series sprockets available. But 67-3050 for 1948 A7 standard 19T are not.  Can anyone help?

Offline duTch

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Re: Longstroke 1948 gearbox sprocket
« Reply #1 on: 20.02. 2016 05:27 »

 Not knowing much about longstrokes (=F/A) only thing I can think of is that the original sprocket had the oil scroll, and I doubt you'll find one of those. Subsequently, a substitute common late model part # is likely, as I dare say they are identical to the later sprocket.

 Main basis for my reasoning is I have what I believe is an early box in my '52 Plunger R/Flash, and that had a sprocket with a scroll when it first came my way, and I've since changed it to the available type. Mind you, I knew not otherwise, but it works for me.

 Other will likely know better and be able to throw more light on the subject... *idea*
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

Offline Tomcat

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Re: Longstroke 1948 gearbox sprocket
« Reply #2 on: 20.02. 2016 06:16 »
Draganfly list it on their WWW, but not in stock. http://draganfly.co.uk/index.php/accessories-a-misc/product/14203-
Have you tried Priory Magnetos? Andrew is a member on here and sells Beeza bits. https://sites.google.com/site/priorymagnetos/home
'48 A7 '59 SR '74 850 Commando TDM900

Offline Harry

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Re: Longstroke 1948 gearbox sprocket
« Reply #3 on: 20.02. 2016 11:24 »
Thanks for the suggestions. I'll work on them being the same and ingnore the oil scroll. I didn't now about Andrew and Priory Magnetos.  Perhaps inquire there too. THanks for the help!

Online trevinoz

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Re: Longstroke 1948 gearbox sprocket
« Reply #4 on: 20.02. 2016 21:54 »
Harry,
                   If you are going to use a non scrolled sprocket, you will have to fit a seal in place of the metal housing.
Wouldn't you be using an 18T sprocket?

Offline Harry

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Re: Longstroke 1948 gearbox sprocket
« Reply #5 on: 21.02. 2016 07:15 »
Thanks trevinoz.  I ride mostly in the Adelaide hills and would prefer to gear it down slightly. The rear sprocket/brake drum assembly I have - hard to get - is a large 49T sprocket (sidecar version). So 19T on the front I thought. And my parts book says 19T is standard anyway.