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speedometer needle on wrong side

Started by bigbore2, June 18, 2012, 01:40:57 PM

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bigbore2

Cleaned/lubed my speedo cable, removed speedometer and regreased the first couple plastic/nylon gears and reinstalled.  Speedo needle is now sitting on wrong side of pin [below pin]. Connected  speedo cable to drill and reversed it and needle moves back or counterclockwise, so I know speedo works.  I know I read about this before but a search gave me nothing.  How do I get the needle back counterclockwise all the way to zero.  Magnet? 

FJmonkey

Quote from: bigbore2 on June 18, 2012, 01:40:57 PM
Cleaned/lubed my speedo cable, removed speedometer and regreased the first couple plastic/nylon gears and reinstalled.  Speedo needle is now sitting on wrong side of pin [below pin]. Connected  speedo cable to drill and reversed it and needle moves back or counterclockwise, so I know speedo works.  I know I read about this before but a search gave me nothing.  How do I get the needle back counterclockwise all the way to zero.  Magnet? 
I am gonna take a crack at this... You say you removed gears form the speedo assembly? The speedo works by a system of rotating Rare Earth Magnets (REM) around other REMs in a fixed position. The faster the rotation the stronger the attraction and force to rotate the fixed REM. Now, replace the fixed position with the part that rotates freely and holds the indicator needle. Spin the speedo cable and the needle wants to rotate till it hits maximum speed where the post is located to stop the needle. Not very good for a speedometer right? Ok, now let's add a weak coil spring like we see in watches to store the energy when you wind them up (I am dating myself now, most everyone here still thinks digital watches are a pretty neat idea). The spring adds resistance to the rotational force. The more the spring is rotated the more resistance is required to rotate it even more. Remember that REM in rotation provides more force the faster the rotation happens. A balance of spring force is required to indicate proper speed. If you altered the spring gear position by removing the gears, you may need to fiddle with it some more to find the correct position. On the other hand, I may just be drunk off may ass and thinking the Yellow Power ranger looks really HOT right now....

Anything you touched/removed on the speedo is suspect of the cause of the problem.
The glass is not half full, it was engineered with a 2X safety factor.

'86 Ambulance - Bent frame, cracked case, due for an overhaul
'89 Stormy Blue - Suits my Dark Side

bigbore2

Thanx to whomever put this in the correct category. Owe you a beer.   FJmonkey- I took the cluster out of the fairing and took the speedo out of the cluster.  I did not remove any gears, just maybe a cover to access the gears and the white colored plastic/nylon gear coming out of the cable drive and lubed it and lubed the gear this first gear drives. You explained things very well. You should be a teacher. I know, doesn't pay well enough. We should pay our good teachers more. Your pay is 2 beers.  I was just going to remove again and spin the needle around by hand , if possible, from the backside and hope it stays at zero when I reinstall.

bigbore2

Ok I guess no one has had this problem before.  Well I fixed it and here is how.  The needle was sitting on the underside of the little peg that is at 0 mph just touching the peg instead of sitting on top of the peg. The peg is made of rubber and somehow last time I must of bumped the needle without knowing it  because all I did was to push the needle up and the peg lays over. Once the needle is clear of the peg , it pops back straight up, and my needle is now on the correct top side of the peg.

While I fiddling around with things I noticed that when the needle was on the underside of the peg and I moved it to the right counterclockwise towards the 140 mph mark and let it go, it would return in a clockwise direction to rest again on the underside of the peg. However, now that it is on the top side of the peg in the normal position and I move the needle to 20 or 30 mph or whatever and let go, the needle now moves COUNTERCLOCKWISE to rest again at 0 mph.  I completely don't understand this, but I don't really need to cause my speedo is fixed. Just found it very curious.  Unless, perhaps, I have just discovered the nexus of the universe here on my speedometer gauge.

FJmonkey

Quote from: bigbore2 on June 21, 2012, 02:45:53 PM
Unless, perhaps, I have just discovered the nexus of the universe here on my speedometer gauge.
I think the needle is adjusted to sit at the neutral or resting state of the spring. Any movement away from its resting point causes it return. But that pin is not that big, maybe you did stumble onto some Black Magic speedo stuff...
The glass is not half full, it was engineered with a 2X safety factor.

'86 Ambulance - Bent frame, cracked case, due for an overhaul
'89 Stormy Blue - Suits my Dark Side

bigbore2

FJ- I was thinking the same thing and was tempted to snip off or try to pull out the rubber peg and then see what would happen, but I was happy with the fix and stopped myself there.

fj11.5

i have a few fj speedo,s in the shed, ill disect one in the name of science  :nyam2:
unless you ride bikes, I mean really ride bikes, then you just won't get it

84 Fj1100  effie , with mods
( 88 ) Fj 1200  fairly standard , + blue spots
84 Fj1100 absolutely stock standard, now more stock , fitted with Fj12 twin system , no rusted headers for this felicity jayne

FJmonkey

Quote from: fj11.5 on June 22, 2012, 07:22:52 PM
i have a few fj speedo,s in the shed, ill disect one in the name of science  :nyam2:

Oh yea! really good idea... I have my old failed speedo in the garage as well. I used to take my toys apart when I was younger, I guess I still do. Just now the toys cost more....
The glass is not half full, it was engineered with a 2X safety factor.

'86 Ambulance - Bent frame, cracked case, due for an overhaul
'89 Stormy Blue - Suits my Dark Side

fj11.5

needed the excuse to light the heater in the shed  :good:,
unless you ride bikes, I mean really ride bikes, then you just won't get it

84 Fj1100  effie , with mods
( 88 ) Fj 1200  fairly standard , + blue spots
84 Fj1100 absolutely stock standard, now more stock , fitted with Fj12 twin system , no rusted headers for this felicity jayne

bigbore2