hello
i have bought an emigo speedo which works great but over reads by about a third. i m wondering if the speedo is a 1600 ratio instead of a 1000 ratio. the speedo drive is 1.25 / 1 and i am asking any knowledgeable person on the forum whether a 2/1 ratio speedo drive would be the way forward.
i was talking about this the other day to someone who knows more than me and was told a 2:1 speedo is the thing to have.
dont take my word for it. i didnt have a clue but he was adamant
hi cornish bob
i followed up from your reply and ordered a 2/1 speedo drive from a different supplier than where i bought the speedo and drive.
i was a little disappointed with them as they promised back up when i bought the items not knowing if the ratios would work .
i emailed the online shop but had no answer.
I will let you know the result and accuracy when i fit the 2/1 drive.
hi mate. i should say i was talking as a complte dont knower. it was just funny i was talking to some one who should know. i think he said it was actually 1.9:1 but as you dont see many speedos at that ratio a 2:1 is ok as the diference would be not worth worrying about
Easy way to remember is find the correct speedo drive gearbox, you need to divide the number on the speedo by 800.
So if your Speedo says 1000, 1000/800 = 1.25 (15:12)
If your Speedo says 1600, 1600/800= 2 (2:1)
You may see other Speedo numbers out there but for magnetics they need to divide by 800 to give you your required Speedo gearbox ration.
This is correct at least in miles. Km/H speedos might differ.
hi allen
its an emigo speedo with no ratio given that i can see.
if it doesnt read correct and you know the emgo is 2:1 the suitable drives are easy to match and cheap
well,
i fitted the 2/1 speedo drive and is accurate enough to assert that the speedo head must be near a 1600 rpm unit.
bob , i would say your speedo expert mate was spot on and the slight difference of 1.9 / 1 allows the speedo head to slightly over read and therefore remain legal as its unlawful to under read.
i dont feel the emigo drive unit to be as well built as a original smiths and the unit goes a little stiff when the spindle is tight so i guess it needs a thin washer in there to stop distortion.
i dont think the speedo cable i bought is as good as the original either except the square dive on the original has worn about 0.5 mm.
finally i m riding legally with a working speedo , so thanks for all the comments. however i have a 1575 chronometric speedo head on my a10 which has spot on accuracy and maybe i should have gone that route.
thats good. the guy seemed to know what he was saying was right
emgo isnt the best quality. coming from a harley background i'm used to all these yankee things.
i would say emgo stuff is middle range but they dont seem to go wrong. its all chinese or taiwanese or something after all,
i have a beaten up smiths on my little baby. dont know if it works yet. if it does hurrumph if not i have a drag specialties 1 7/8" micro 2:1
glad my input was helpfull
HI cornish bob and Allen G, could you help sorting my quest out,bob would you mind asking your learned friend what speedo gear box drive i require for my usa impoerted 1966 A65L the speedo is 1600 but it has a 19inch rear wheel that some usa bikes had Allen G you might know could you help, thanks Roy
Hi, the rim size shouldn't make much of any difference as the overall tyre diameter between a 3.50:19 and a 4.00:18 is the same, you should find the overall circumference measures about 82". There will be more change from using a low profile tyre with either sized rim than if you stuck with the original tyre sizes for the given rim.
i would have thought a 2:1 ratio drive. i will enquire but at the moment hes somewhere in france
1600 seems to be a more general ratio that would take into account various factors such as 18 or 19 " driven wheels and probably still over read slightly. for accuracy similar to gps a chronometric speedo of the 1575 type would be the way to go IMO. but they are bloody dear if you can find one. i think mines of a ajs 650.
from about 1967 A65 went from 1600 speedo to 1000 (150mph speedos instead of 120mph) Obviously the speedo drive changed from 2:1 to 15:12 (or 1.25:1 as some sellers list them)
However IF you have a 1600 speedo regardless of the bike it should have a 2:1 speedo with it.
Magnetic speedos are renowned for showing a slower speed over time. If your lucky enough to get a good one, or have it refurbished by someone decent.. and your cable inner doesn't protrude too far into the speedo which will damage the mechanism... Then they can be quite accurate for a good many years.
I fitted a genuine, unmolested from factory, used one a couple of years ago for my Thunderbolt. I have a Quadlock charging setup/phone mount on this bike. So I can use my satnav off my phone (Waze app), meanwhile it charges up, its vibration proof/resistant - I can see the screen clearly at any speed anyway. Anyway it does also display the speed. But this is quite small so I have only checked it so far at 30 and 40 mph. At those speeds my original Smiths is spot on accurate. I do have some speedometer apps which will display the current speed in a much larger size without the sat nav feature. So I will do this, this weekend and compare.
Now since some tiring magnetic speedos will under read. At the discretion of the local constabulary you do have 10% +1mph before they will fine you. at 10%+2mph you will get a fine.
hi allan
yes your right, a good magnetic speedo can be very accurate if you can find one. i have a mixed lot of u/s and 2 that have opposite rotation and work with a drill holding the cable but not when connected to the speedo drive. it was causing a lot of frustration. the new emigo speedo i fitted is not as accurate with a 2/1 drive as you would expect a chronometric speedo to be. mine over reads mph a tiny amount but is close enough when the other option is a shagged smiths magnetic one. i would be interested to know the current price of a magnetic speedo rebuild is ,compared to the £80 i paid for the emigo unit.
Quote from: EDDIE SIMPSON on 26 Apr, 2024, 23:20 hi allan
yes your right, a good magnetic speedo can be very accurate if you can find one. i have a mixed lot of u/s and 2 that have opposite rotation and work with a drill holding the cable but not when connected to the speedo drive. it was causing a lot of frustration. the new emigo speedo i fitted is not as accurate with a 2/1 drive as you would expect a chronometric speedo to be. mine over reads mph a tiny amount but is close enough when the other option is a shagged smiths magnetic one. i would be interested to know the current price of a magnetic speedo rebuild is ,compared to the £80 i paid for the emigo unit.
I just used Classic Speedometers. £115 for a service/repair + any parts Great service I thought...
Cheers Glenn
hi glen,
i m happy with the emigo once i had the correct 2/1 drive. i had to open out the speedo rubber to make it fit though.
i ve spent loads of money on magnetic rev counter and speedo repairs in the past. the problem is a wearing bush inside but the unit is held together with rivets rather than screws so not maintenance friendly.