Digital speedometer troubles

Fishermanblues

New Member
Aug 24, 2008
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Tucson Az
I got a new digital speedometer yesterday because my old mechanical one broke. It works fine while I'm pedaling but whenever I start the engine the speedo shuts off and resets itself. It isn't the wireless type, I've heard that the wireless ones in particular have trouble with interference from the cdi. I tried wrapping the wire in aluminum foil and grounding it to the frame to shield it from whatever interference the cdi might be causing.

Does anyone have any ideas for fixing it?

Thanks,
Andrew
 

Ghost0

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Mar 7, 2008
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Bellingham, WA
Replace your spark plug wire, and while your at it the plug, with good ones. The stock plug wire has no shielding. Get a good EMI suppression plug wire. It solves the problem.
 

wheelbender6

Well-Known Member
Sep 4, 2008
3,990
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TX
The engine spark causes your speedo to lose its settings.
Mine goes blank upon cranking, so I quickly enter through the setup menu and it begins to work again. Give it a try.
 

Fishermanblues

New Member
Aug 24, 2008
38
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0
Tucson Az
I went over to autozone and bought a motorcycle wire for $5, chopped it in half and screwed it onto the cdi - that fixed it.
I will have to wait til tomorrow to see how fast I really go .fly because I don't want to anger the neighbors too much.

Thanks for the help everybody,
Andrew(^)
 

Norman

LORD VADER Moderator
Staff member
Jan 16, 2008
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pampa texas
at radio shack they are supposed to sell a ring called a shunt,choke, shoot I can't think of the name maybe a ferrite ring? but you put the speedo wire through it one turn and its supposed to stop the RF from messing with the speedo.
Maybe someone knows the name I've, seen other posts about this problem and have had it too I cured the problem by not using the speedo on a motorized bike got it on the pedal only one, I'm lazy I hardly ever ride it.rotfl
Norman
 

jasonh

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Jun 23, 2008
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Longmont, CO
Are you referring to one of these Norman?

Snap Choke Core - RadioShack.com

You can also replace the wire for the sensor with a twisted pair (like in ethernet cable - + and - twisted around each other) and that should shield out interference too.

Yes thats the thing thanks.
Norman
 
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mechanickid

New Member
Aug 7, 2008
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nh
i have this problem too, i've replaced the spark wire with ngk snowmobile spark plug wire, and it didn't help. i have the 1 dollar kind from ebay.
 

2door

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Staff member
Sep 15, 2008
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Littleton, Colorado
I'm on my third digital speedo in 700 miles. The first one didn't work at all. The 2nd one a wireless, would only go to 12MPH and the 3rd one, a WallyWorld wired cheapo worked great for about six weeks now it dies from what most of you say is ignition interference. I thought that too but wondered why it worked flawlessly for 6 weeks before having problems. I tried it this weekend, no motor, pedaled around and the thing went blank and lost its programing just like it does with the engine running. Okay, so it's not because of RF interference so what's happenin? I removed the battery and bent the little clips in to hold the batt tighter thinking maybe the batt was shaking loose from road vibration and bumps. That didn't help. It still goes blank, engine off.
I'm in the market for a good old cable drive speedo. No batteries, no electronics, no problems.
Tom
 

marioaz

New Member
Dec 15, 2008
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Prescott, Arizona
Just bought the 12 function Schwinn bike computer from Walmart. Seems to work just fine. Did replace the stock wire and end with a solid copper core motorcycle wire and NGK plug end. No problem , yet.
 

Josh380

New Member
Feb 13, 2009
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Aliso Viejo, CA
Just bought the 12 function Schwinn bike computer from Walmart. Seems to work just fine. Did replace the stock wire and end with a solid copper core motorcycle wire and NGK plug end. No problem , yet.
I have the same speedo. I rode around for about a week (everything but the plug stock), and it worked fine. It just started resetting on me today. The motor tops out at about 27 mph, so I don't really need it...it's just nice to know just how fast I'm going. Weird how it works for only a short period of time, then starts going sideways.....
 

Dave31

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Mar 1, 2008
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Aztlán, Arizona
If you have the type were the computer sets in a base (mounting bracket), sometimes the vibration and bumps can cause a bad connection between the base & computer and it will shut on/off & or reset itself.
 

2door

Moderator
Staff member
Sep 15, 2008
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Littleton, Colorado
If you have the type were the computer sets in a base (mounting bracket), sometimes the vibration and bumps can cause a bad connection between the base & computer and it will shut on/off & or reset itself.
Fair,
Is there a fix for this that you know of? I thought about this being the problem and tried a thick rubber band to hold the speedo in the clip tighter but it still goes blank and resets itself. I'm considering connecting the contacts on the speedo head and the handlebar clip with some small wire soldered to each. If it is breaking contact at these points maybe that will solve the problem. I'll let you know.
Tom
 

Dave31

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Mar 1, 2008
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Fair,
Is there a fix for this that you know of? I thought about this being the problem and tried a thick rubber band to hold the speedo in the clip tighter but it still goes blank and resets itself. I'm considering connecting the contacts on the speedo head and the handlebar clip with some small wire soldered to each. If it is breaking contact at these points maybe that will solve the problem. I'll let you know.
Tom
No I do not know a fix for this problem, I have heard others that have had this problem but they never post what they did to fix it. Just wanted to post it so that others may look into it and make sure the same thing was not happening to them.

Mine has been good so far with no problems. I would guess anything you could do to help keep the contact should work if that is what is happening.
 

2door

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Sep 15, 2008
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Littleton, Colorado
No I do not know a fix for this problem, I have heard others that have had this problem but they never post what they did to fix it. Just wanted to post it so that others may look into it and make sure the same thing was not happening to them.

Mine has been good so far with no problems. I would guess anything you could do to help keep the contact should work if that is what is happening.
Didn't work...:(
I didn't solder the contacts but I did wedge 2 narrow strips of silver contact material between the mount and the head. I discovered that the contacts in the head are tiny balls mounted in springs. No way to solder them but the extra material between the contacts didn't help. I also experimented with moving, even disconnecting the head from the mount while riding did not duplicate the problem so it sort of ruled out the theory that a bad connection was causing the head to loose its program. I give up. It's trash can time for the digital speedo and off to ebay or craigs for a cable drive. Thanks for your input, Fair.
Tom
 

azbill

Active Member
May 18, 2008
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Fountain Hills, Arizona
if going the cable route...
I would suggest using something of a higher quality than the 'sports' one for a bicycle
I have killed 3 of them, they just don't hold up to the speeds we do

I would go with a whizzer one or something of that higher caliber
 

2door

Moderator
Staff member
Sep 15, 2008
16,326
124
63
Littleton, Colorado
if going the cable route...
I would suggest using something of a higher quality than the 'sports' one for a bicycle
I have killed 3 of them, they just don't hold up to the speeds we do

I would go with a whizzer one or something of that higher caliber
Good idea, Bill.
I saw one at a motorcycle junk yard last week on a small scooter with spoked wheels. It was mounted in a dash panel with a keyed ignition switch and light switch. The drive appeared to be adaptable to a bike front wheel but the thief who runs the place wanted $50.00 for the head and drive. I'll keep looking.
Tom