1980 RX7 LS White with Gold Stripes: What would a fair price be?

[t_g_farrell]

There is no signal generated, the speedo is an old school analog that has the cable spinning
a magnet around the needle armature which causes the needle to move. Its very precisely
made and can get out of whack by dirt and stuff building up in the speedo, or by well
intentioned lubing of the mechanism or just age.

A bouncing speedo at low speed may be a sticking cable. You can unplug the tranny end
and remove the cable, clean it and very lightly lube and reinsert. If you get really
ambitious while its out unplug the other end from the speedo and clean and blow out the
casing with compressed air and some light solvent. Very rarely do the tranny gears go
bad. Its usually a cable or speedo that causes problems. The cable is easy to address to
rule it out.

[infernosg]

Originally Posted by t_g_farrell

There is no signal generated, the speedo is an old school analog that has the cable spinning
a magnet around the needle armature which causes the needle to move. Its very precisely
made and can get out of whack by dirt and stuff building up in the speedo, or by well
intentioned lubing of the mechanism or just age.

I should have clarified the magnetic field is what I was referring to by "signal." If the speedometer isn't working either the magnet isn't spinning or something is disrupting the magnetic field. The stuck needle tells me something is gunked up inside the speedometer. There's no way the proper magnetic field is being generated to indicate 35 mi/hr without the cable spinning. If the speedometer works above 35 mi/hr it's functioning properly but is getting stuck for some reason. If it doesn't work at all either the cable isn't spinning or there's something wrong internally with the speedometer.

Originally Posted by t_g_farrell

A bouncing speedo at low speed may be a sticking cable. You can unplug the tranny end
and remove the cable, clean it and very lightly lube and reinsert. If you get really
ambitious while its out unplug the other end from the speedo and clean and blow out the
casing with compressed air and some light solvent. Very rarely do the tranny gears go
bad. Its usually a cable or speedo that causes problems. The cable is easy to address to
rule it out.

I didn't realize you could pull the entire cable out through the transmission end. I'll have to give that a try. I love that you can easily reach the back of the speedometer in SA's.

Believe it or not I once broke the speedometer drive gear on the transmission output shaft on my FC once. I changed the final drive ratio and was changing out the speedometer driven gear to account for the difference. I didn't realize the housings were different and ended up crashing the gears into each other. 20+ years of gear oil apparently makes plastic quite brittle.

[Mperell1]

Thank for all the comments. Sorry I didn't respond earlier, long week at work. I took it to the mechanic and they said it wasn't a problem with the cable but with the speedometer itself. The speedometer just waves back and forth especially at higher speeds, does that mean anything? Thanks for all the tips.