speedometer no longer accurate

asofdjhkljashdl · Post by **asofdjhkljashdl** » Wed Jun 18, 2008 6:01 pm

I've been driving the coupe to work every day (2mi roundtrip) for a
couple months. As of yesterday, the speedometer stopped displaying my
real speed. The speedo displays 10-15 now when I'm going 25-35, and
is much more 'jerky' when moving. The tachometer is fine, and other
electrical connections seem fine (headlights, tail lights, interior
lights, etc).
Any ideas?

zinc2u · Post by **zinc2u** » Wed Jun 18, 2008 7:53 pm

Although you may have a bad speedometer, the "jerky" readings while underway can be caused by the speedo cable needing lubrication. You can disconnect it at the engine (next to dipstick), pull out the cable, lubricate it, and slide it back into the sleeve. Check the cable where it goes from the firewall to the engine/tranny and see if the cable sheath has any damage or sharp bends. Near the master cylinder is a spot where it takes a 90 degree bend and the cable or the sheath could be damaged at that spot.
When you pull out the cable, inspect it to see if it is frayed.
If so, you need a new cable.
good luck,
Dale

> I've
> been driving the coupe to work every day (2mi roundtrip) for a > couple > months. As of yesterday, the speedometer stopped displaying my > real speed.
> The speedo displays 10-15 now when I'm going 25-35, and
> is much more
> 'jerky' when moving. The tachometer is fine, and other
> electrical
> connections seem fine (headlights, tail lights, interior > lights, > etc).
> Any ideas?

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John · Post by **John** » Thu Jun 19, 2008 4:45 pm

Speaking of speedometer accuracy, is there any way to adjust the
speedometer to reflect actual speed? Or is that purely a function of
tire size?
Mine shows in the order of 5-6 miles an hour faster than the car
really is going. Which means miles piling up on the odometer are more
than the distance the car has actually covered by about 10%.

friend · Post by **friend** » Thu Jun 19, 2008 10:51 pm

It might be that some one put a Constant transmission speedo gear in there instead of the one for a full synchro trans. It does what you are talking about.
Bill

> -----Original Message-----
> From:
> 2cylinderhondas@yahoogroups.com [mailto:2cylinderhondas@yahoogroups.com] > On > Behalf Of > John > Sent:
> Thursday, June 19, 2008 4:46
> PM
> To:
> 2cylinderhondas@yahoogroups.com
> Subject:
> [2cylinderhondas] Re: speedometer no longer accurate
> Speaking of speedometer accuracy, is there any way to adjust > the > speedometer to reflect actual speed? Or is that purely a function > of > tire size?
> Mine shows in the order of 5-6 miles an hour faster
> than the car
> really is going. Which means miles piling up on the odometer > are more > than the distance the car has actually covered by about > 10%.

zinc2u · Post by **zinc2u** » Fri Jun 20, 2008 12:56 am

In my earlier msg, I mentioned the speedo cable makes a 90 degree bend by the master cylinder. That was incorrect. The speedo cable comes out of the firewall on the right side and goes directly to the speedometer gear.
When you disconnect the speedometer cable, you should be able to turn the cable and it should turn smoothly and not stick. You could attach a variable speed drill to the cable and turn it slowly and observe the reading on the speedometer.
Dale

> Although you may have a bad speedometer, the "jerky" readings while > underway can be caused by the speedo cable needing lubrication. You can > disconnect it at the engine (next to dipstick), pull out the > cable, lubricate it, and slide it back into the sleeve.
> Check the cable where it goes from the firewall to the engine/tranny and see > if the cable sheath has any damage or sharp bends. Near the master > cylinder is a spot where it takes a 90 degree bend and the cable or the sheath > could be damaged at that spot.
> When you pull out the cable, inspect it to see if it is
> frayed. If so, you need a new cable.
> good luck,
> Dale
> > I've
> > been driving the coupe to work every day (2mi roundtrip) for a > > couple > > months. As of yesterday, the speedometer stopped displaying my > > real > > speed. The speedo displays 10-15 now when I'm going 25-35, and > > is much > > more 'jerky' when moving. The tachometer is fine, and other > > electrical > > connections seem fine (headlights, tail lights, interior > > lights, > > etc).
> > Any
> > ideas?

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Miles · Post by **Miles** » Fri Jun 20, 2008 9:22 pm

In one of the road tests for the Honda 600 Sedan it claims speedo
innacuracy by 5 or 6 mph. The other thing is and I have mentioned
this before is; the early AN600 came with 5.20 x 10 bias ply tires
and a non synchro trans. The later sedans had 145SR 10 Radials which
are slightly shorter, mismatching these items will change your speed.
The old myth of rolling the speedo backwards does not work is
incorrect. It may not have worked on Ferris Buehlers Day Off's
Ferrari, but it does work on a Honda 600, I've tried it!
Miles

--- In
2cylinderhondas@yahoogroups.com
, goinhm@... wrote:
> In my earlier msg, I mentioned the speedo cable makes a 90 degree
bend by
> the master cylinder. That was incorrect. The speedo cable comes
out of the
> firewall on the right side and goes directly to the speedometer
gear.
> When you disconnect the speedometer cable, you should be able to
turn the
> cable and it should turn smoothly and not stick. You could attach
a variable
> speed drill to the cable and turn it slowly and observe the reading
on the
> speedometer.
> Dale
> Although you may have a bad speedometer, the "jerky" readings
while
> underway can be caused by the speedo cable needing lubrication.
You can disconnect
> it at the engine (next to dipstick), pull out the cable,
lubricate it, and
> slide it back into the sleeve. Check the cable where it goes from
the
> firewall to the engine/tranny and see if the cable sheath has any
damage or sharp
> bends. Near the master cylinder is a spot where it takes a 90
degree bend
> and the cable or the sheath could be damaged at that spot.
> When you pull out the cable, inspect it to see if it is frayed.
If so,
> you need a new cable.
> good luck,
> Dale
> I've been driving the coupe to work every day (2mi roundtrip) for a
> couple months. As of yesterday, the speedometer stopped displaying
my
> real speed. The speedo displays 10-15 now when I'm going 25-35, and
> is much more 'jerky' when moving. The tachometer is fine, and other
> electrical connections seem fine (headlights, tail lights, interior
> lights, etc).
> Any ideas?
> **************Gas prices getting you down? Search AOL Autos for
> fuel-efficient used cars. (
http://autos.aol.com/used?
ncid=aolaut00050000000007)

John Ph. Graf · Post by **John Ph. Graf** » Sat Jun 21, 2008 7:17 am

> The old myth of rolling the speedo backwards does not work is
> incorrect. . . . . It does work on a Honda 600, I've tried it!

Oh my, the worms you've uncovered!
My 72 sedan still has the original bias ply tires on it. I have suspected
the speedo reads incorrectly but have not tested it like I have the 71
sedan, which is riding on radials.

friend · Post by **friend** » Sat Jun 21, 2008 8:21 am

Miles;
That's interesting, but I read it differently. The bias ply tires did two things, gave a softer ride and at speed caused the tire to squeez so that less tire tread was meeting the pavement. So the tire at 50 mph was really taller than the radial which flatens out more keeping more tire on the road, better handling. I have some NanKing tires from China that are bias nylon tires, they will try and run the grooves CALTRANS put in the freeways to keep the cars from hydroplaning when it rains. Just the worst tires I have ever put on a car. But I still have them with a set of "Port-a-wall's" installed, nice touch at shows.
Bill

> -----Original Message-----
> From:
> 2cylinderhondas@yahoogroups.com [mailto:2cylinderhondas@yahoogroups.com] > On > Behalf Of > Miles > Sent:
> Friday, June 20, 2008 9:22
> PM
> To:
> 2cylinderhondas@yahoogroups.com
> Subject:
> [2cylinderhondas] Re: speedometer no longer accurate
> In one of the road tests for the Honda 600 Sedan it claims speedo
> innacuracy by 5 or 6 mph. The other thing is and I have mentioned > this > before is; the early AN600 came with 5.20 x 10 bias ply tires > and a non > synchro trans. The later sedans had 145SR 10 Radials which > are slightly > shorter, mismatching these items will change your speed.
> The old myth
> of rolling the speedo backwards does not work is
> incorrect. It may not
> have worked on Ferris Buehlers Day Off's
> Ferrari, but it does work on a
> Honda 600, I've tried it!
> Miles
> --- In
> 2cylinderhondas@ yahoogroups. com
> ,
> goinhm@... wrote:
> > In my earlier msg, I mentioned the
> speedo cable makes a 90 degree
> bend by
> > the master cylinder. That
> was incorrect. The speedo cable comes
> out of the
> > firewall on the
> right side and goes directly to the speedometer
> gear.
> When you disconnect the speedometer cable, you should be able to > turn the
> > cable and it should turn smoothly and not stick. You could attach
> a variable
> > speed drill to the cable and turn it slowly and
> observe the reading
> on the
> > speedometer.
> Dale
> > Although you may have a bad speedometer, the "jerky"
> readings
> while
> > underway can be caused by the speedo cable needing
> lubrication.
> You can disconnect
> > it at the engine (next to
> dipstick), pull out the cable,
> lubricate it, and
> > slide it back
> into the sleeve. Check the cable where it goes from
> the
> > firewall
> to the engine/tranny and see if the cable sheath has any > damage or sharp
> > bends. Near the master cylinder is a spot where it takes a 90
> degree bend
> > and the cable or the sheath could be damaged at that
> spot.
> > When you pull out the cable, inspect it to see if it is
> frayed.
> If so,
> > you need a new cable.
> > good
> luck,
> > Dale
> > I've been driving the coupe to work every
> day (2mi roundtrip) for a
> > couple months. As of yesterday, the
> speedometer stopped displaying
> my
> > real speed. The speedo displays
> 10-15 now when I'm going 25-35, and
> > is much more 'jerky' when moving.
> The tachometer is fine, and other
> > electrical connections seem fine
> (headlights, tail lights, interior
> > lights, etc).
> > Any
> ideas?
> > ************ **Gas prices getting you down?
> Search AOL Autos for
> > fuel-efficient used cars. (
> http://autos. aol.com/used?
> ncid=aolaut00050000 000007)