I am attempting to repair the speedo on the 67 Atlas The head is a 1600 one and I need to know what ratio the drive gearbox should be.Its a bit more complicated by the fact that its a 19" rear wheel, I think this was std for Uk bikes but the yanks had 18" wheels . Its a 120 speedo, I have a 15/12 box on the bike and a rough 19/10 spare .I think the 15/12 goes with a 1000 clock (150mph?) ,and the 16oo clock should have a 2/1 box??,
Previously robert_tuck wro…
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The 1600 speedo uses a 2:1…
The 1600 speedo uses a 2:1 drive and the 1000 uses a 15:12 or 1.25:1. The 19:10 is for the smaller wheeled bikes, 17".
The speedo number refers to the number of turns per mile, so with a bit of maths and tyre data.....avon list their tyres with rolling circumference or diameter.
Paul
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Thanks Paul, If I use the…
Thanks Paul, If I use the 19/10 it would appear that the speedo would read slow ?, but I
understand that with magnetics some adjustment is possible. Must be better than the 15/12. Edited, thats no good the 19/10 is worn out. So I have a 15/12 that Anna says is right and a 1600 clock that looks fine but needs a service, Is it likely that I could get it adapted to run with the 15/12 which is in good nick as is the cable?.The wheel circ is 2.090. (19")
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Previously robert_tuck wrote:
hello, it should be 15.12 on all later models