SF Smiths speed meter

Cyriel

Cyriel

Full member
Need some help. My SF Smiths speed meter counts only 60 km/h when im driving 80 km/h (navigation measurement)
I have a 12/15 ratio in my front wheel. Laverda type 1 brake.

Does someone has the knowledge to sort this problem?
Thanks in advance.

IMG_20250418_164124.jpg
 
afaik your speedo needs the 11/22 for THAT speedo. The "1000" at the bottom inscription
is rhe hint. Seems that has been originally a GT speedo which would have the clock face ending at 190 km/h.
For the SF speedo there is a "600" there.
Might be that I've some written proof somewhere but can take a little time to find it.
Ermesto
 
Just out of interest does the trip meter read correct ? The trip is gear driven and cant really go wrong but the speedo is magnetic driven and that is adjustable.
 
Cyriel, do you have the Grimeca from brake? The reason I ask is I've just bought a KPH speedo for my bike on advice that it is okay for my Laverda front brake (1970). I'm hoping I bought the correct speedo, yep I know this is no help to you.

I've just looked up the cost of a set of gears for the front wheel to change the ratio to suit your speedo, Geez!! with the exchange rate at the moment that would cost me in OZ dollars just under $600 without postage!

Cheers
 
OTR002 said:
Cyriel, do you have the Grimeca from brake? The reason I ask is I've just bought a KPH speedo for my bike on advice that it is okay for my Laverda front brake (1970). I'm hoping I bought the correct speedo, yep I know this is no help to you.

I've just looked up the cost of a set of gears for the front wheel to change the ratio to suit your speedo, Geez!! with the exchange rate at the moment that would cost me in OZ dollars just under $600 without postage!

Cheers
Click to expand...
Laverda type 1 brake.
 
Paddy said:
Just out of interest does the trip meter read correct ? The trip is gear driven and cant really go wrong but the speedo is magnetic driven and that is adjustable.
Click to expand...
The speedo is completely rebuild few kilometers ago. I will check the trip meter thanks.
 
Ernesto said:
afaik your speedo needs the 11/22 for THAT speedo. The "1000" at the bottom inscription
is rhe hint. Seems that has been originally a GT speedo which would have the clock face ending at 190 km/h.
For the SF speedo there is a "600" there.
Might be that I've some written proof somewhere but can take a little time to find it.
Ermesto
Click to expand...
Hi Ernesto, thanks for your reply! So i need to change the ratio from 12/15 to 11/22 gears?
 
for Smiths speedo with the number 600 in the bottom of the dial plate (if its original) you need 12/15 front wheel gears

for Smiths speedo with the number 1000 in the bottom of the dial plate (if original) you need 11/22 front wheels gears

most bikes with ND clocks (indiidual clocks not box of clocks) 750 or 1000 need 9/25 but note that items used on drum brake triples or twins is a differtent profile to those of disc brake models twins or triples even though they are both 9/25

I am not sure about Grimeca equiped twins, can someoine investigate that if you own one? I dont believe the gears are different from the (very rare) 190kph speedo to the 240kph speedo, but could be wrong and would like to know.
CLEM
 
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