Smiths chronometric tacho

[Billybream]

adm edit: split from http://www.a7a10.net/forum/index.php?topic=6884.0

Hi Mark and welcome to this forum, great help for me.
Try Armour,s for the exhaust.
Smiths chronometric tacho, hope your wallet,s deep, but they can still be found, I,ve just ordered one but mine is 3 to 1 anti clockwise with drive from the oil pump as per RGS.

[duTch]

  G'day Mark, good luck with it, I'll suggest turning your existing handlebars upside down, I did it with my original Road rocket for a bit in the seventies as  a novelty, worked a treat , but not my style- may or not work for you.
      I may be wrong, but doesn't  the RGS tacho drive run off the oil pump through the inner timing cover- much cleaner, but yea gotta go with what yea got, cheers and welcome
                                                                  duTch

[chaterlea25]

Hi All,
Dutch, Yes RGS rev counter is driven off the oil pump 3:1 left handed
Mark already has the earlier type drive from the magneto which is why I offered the info for this

HTH
John

[trevinoz]

John,
             Are you sure that Goldies use a 4:1 tacho?
I thought that they used the RC83, same as the Rocket.

Trev.

[Oscarmark]

I have been told that my tacho drive is 2:1 off the magneto?

[chaterlea25]

Hi Mark,
Yes, mag runs at half engine speed so the total reduction is 4:1

Trev,

John,
             Are you sure that Goldies use a 4:1 tacho?
I thought that they used the RC83, same as the Rocket.

No thats not what I said, I am going on the word from a goldie owning friend who's rev counter has/ is giving a lot of problems, Again to the best of my knowledge the goldie rev drive is 1:1 meaning that the cable /rev counter is running at half engine speed
I suggested fitting a 2:1 drive and recalibrate the rev counter to 4:1 ??

I wil know for sure in a couple of days when I go and see another DBD

Has anyone tried one of the new Smiths electronic rev counters or speedos??
http://www.smithsspeedos.co.uk/

Regards
John

[trevinoz]

Sorry John,
                       I wrote that idiot about face.
I should have said Goldies use a 4:1 tacho, same as the Rocket, magy driven.

Trev.

[chaterlea25]

Hi Trev,
Sorry for the long delay in replying,
Now I'm totally confused   

This listing shows the RC1302/00 as fitted to both the Goldie and the A10 which agrees with whats on my friends Goldie
http://www.flickr.com/photos/9383961@N05/3025208238/in/set-72157608955201989/lightbox/

However,
http://www.bsagoldstar.co.uk/price_list/price_list.htm
lists the goldie drive box as 1:1

Regards
John

[wilko]

For a mag driven tacho 1.1 drive for 2.1 tacho. For 4.1 tacho you need 2.1 drive.  Then you have reverse or non reverse drives.You could use either as long as the drive is right. I have a reverse drive 4.1 tacho that needs the cable driven backwards which was  originally used on Enfield twins. Any desperate Enfield nuts who want to swap for normal direction 2.1?

[Topdad]

Hi John, re your quiery about the elecy speedos and tachos ,spurred me to contact them looks like a dead duck for mag fitted bikes waiting a reply from them re this will post when got regards BobH.

[Oscarmark]

The large brass drive fitted to the magneto drive has the number 2:1 marked on it.

?

[chaterlea25]

Hi All,
Maybe just to clarify again
The listing mentioned lists the same RC1302/00 for both the A10 and Goldie, as you can see on the photo theres no indication of ratio??
Mark,
Yes, your A10 drive box 2:1 driven from camshaft running at half engine speed produces a ratio of 4:1

The Gold Star drive box has a ratio of 1:1 so the rev counter should be 2:1

BUT if both are marked RC1302/00 ?? How do we know the instrument ratio without a test rig ??

Regards
John

Still in the market for a 1303L ????

[duTch]

 An old thread, but kinda related, so....if anyone has this knowledge I'll be grateful 
 
 I've done a search for something I didn't expect to find....

 What I need to confirm/know please is;

 1> Thread size/pitch of #113   Part Number 65-9165

 2> Distance 'Between Centres' of the tacho drive/cover plate  screws as above ?
              (Cover plate;#112... / Screws;#113...Part Number 65-9165)

 Hopefully the pic below will explain.....


 NB- doesn't matter if it's in fractions/decimals/metric/chains/furlongs/links/binary/cubits/£,s,p/bitcoin**, I should be able to convert, so long as its fairly precise within .001...

 **conditions apply

 Thanks in advance....

[muskrat]

G'day duTch.
Thread is 3/16 whit. c/d is 1,9/16" and hole size is 1,1/8".
Cheers

[duTch]

 Thanks Musko...now to convert that to something difficult...