Topic: wrong speedometer tach ratio

[aminemed]

Hi

Just a bought an aftermarket speedometer (attached the picture) for my CB 750, and made a big mistake, i ordered the speedometer with the wrong ratio:

instead of ordering a 2240:60, with a ratio 1:4 i've ordered one with ratio 1:1 60mph = 1000 rpm

Cannot return it.

Is there anything i can do to fix this ? changing the cable maybe ?

[Jimray23]

Probably have to change the driver. But im just guessing. By driver i mean the gear on the front wheel.

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Jim
1979 kz1000b ltd
    stage 3 cams
    pod air filters
    4-1 open exhaust(no muffler)
    full rewire
    dyna-s ignition
    dyna 3 ohm coils

[aminemed]

u mean replace it by a 1:1 gear ?

[Bodi]

A different ratio front wheel speedo drive - that fits - is not something you're likely to find. Making a new gear set for the original housing - possible, but not for the casual machinist. A machine shop could make them but not for cheap.
There are inline gearboxes to change drive speed but these are made for cars and I expect the fittings wouldn't be compatible, plus -45% is a big change and probably unavailable.
Overall, best to get a speedo with the correct ratio...

[aminemed]

well, it means that i'm just going to throw that away.. ! its brand new !

[Scott S]

 The one you have is used on Harley's, I believe. Someone will want it.

[Jore]

You could always work out the equivalent speeds with that speedo and make a new face for it, that's what i plan on doing with mine.

[strynboen]

not fun..if he only use the first 1/4 part of the dial..to get full speed. indikation
 .a spedo need to be harmonic..100 miles/160 kmt abaut a 2 am../2 o clock

[aminemed]

how big will be my speed difference between my speedo and reality ?? 5% ?

[strynboen]

at some speeds it almost perfekt..and up to 10% vrong at the vorst..mine is metric and indikates 170 at 160 kmt..i vas feeling so happy..until i faund aut...so better dont thek

[aminemed]

to be honest I never go further than 60mph, is it still the same speed displayed ?