Half baked idea: fixing the mechanical speedo issues.

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rebelrider
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Half baked idea: fixing the mechanical speedo issues.

Post by rebelrider » Sun Jul 21, 2019 12:43 am

I've read about, and experienced directly, the four main shortcomings of the Ural mechanical speedometer.

1: gauge needle wobble
2: incorrect speed reading
3: can't see the gauge at night
4: gauge fogging up after rain

I haven't actually seen anyone solve these issues. Maybe someone has and I just missed it? If I did, let me know.
In the meantime, I have an idea to fix issues 2 and 3, maybe 4.

My thinking is that If I could record what my speedometer is doing against my GPS, I could come up with a "calibrated" gauge face that actually has the numbers in the right place. If I drilled out the numbers, they might let light through and be lit up at night. Still trying to figure out how to illuminate the needle though. And the trip odometer. Another idea might be to attach some kind of faring to the top of the speedometer with some LEDs in it. Not sure if that would cause a reflection issue.

A while back, I was having trouble with my aftermarket tachometer fogging up after rain also. A year or so ago, I completely sealed it up with silicone. Even the vent holes. Hasn't fogged up since, and I've had no issues yet with the vent holes being sealed. I'm thinking the same could be done to the speedometer.

Anyone ever solve the needle wobble issue? I wonder if a bit of grease on the spring just under the needle would give a dampening effect.
Mike
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Re: Half baked idea: fixing the mechanical speedo issues.

Post by wooden nickel » Sun Jul 21, 2019 5:06 am

For the lighting, I found 360 lumen BA9 lamps. They are too bright unless you only use 1 and it works best in the rear hole. Too much glare in the front position. The ones I found barely fit and are a bit too long so I have to run one wrap of electrical tape around tube and the lamp socket or it will fall out of the speedometer.
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Re: Half baked idea: fixing the mechanical speedo issues.

Post by Mr Wazzock » Sun Jul 21, 2019 6:38 am

1: gauge needle wobble
2: incorrect speed reading
3: can't see the gauge at night
4: gauge fogging up after rain
1. I just suck it up. I assume the average is what it is. Mostly.

2. According to our roadside "what's your speed" indicators, it seems quite accurate at 30 - 40 mph. But in any case I assume it is 10% optimistic, as is quite commonly the case with most speedos. So if it's waggling between 50 - 60 and the average is 55, minus 10%, it's 50 then. :D (Also bearing in mind this is a CT with smaller wheels so all else being the same as the 19" wheel models it can't be precisely accurate anyway.)

3. Hardly do any night driving so can't comment. (And not a problem if I don't do any night driving. :D)

4. Change the bulbs to LED ones. It's the heat of the filament bulbs that makes the fogging. Altho sun shining on it can do the same thing.
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Re: Half baked idea: fixing the mechanical speedo issues.

Post by Mr Wazzock » Sun Jul 21, 2019 6:46 am

Anyone ever solve the needle wobble issue? I wonder if a bit of grease on the spring just under the needle would give a dampening effect.
Personally I wouldn't. Early on my dealer told me don't squirt anything into the speedo like oil or WD40 (I was going to do the latter) cos it will just f*ck up the internals so they'd probably stop working altogether.
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Re: Half baked idea: fixing the mechanical speedo issues.

Post by Mr Wazzock » Sun Jul 21, 2019 6:54 am

that If I could record what my speedometer is doing against my GPS, I could come up with a "calibrated" gauge face that actually has the numbers in the right place.
Too much of a faff IMO. Once you know what the difference is you can do it your head. Like I said probably 10% optimistic so e.g. I just subtract 10%.

I think in the UK we're not allowed to stick a homemade scale over our speedos, possibly illegal. Thin bits of tape as markers are OK.
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Re: Half baked idea: fixing the mechanical speedo issues.

Post by Lokiboy » Sun Jul 21, 2019 7:11 am

A lot of work for little return IMHO.

One useful thing you can do, is figure out the trip meter reading versus actual. I found mine to be about 4% off. (The speedometer will be off the same percentage) So what I would do to convert to miles and then figure out my mpg instead of multiplying by .62 I would multiply by .65

For riding at night, what I did was take gloss white paint and make a mark above the 40 and the 50 mph. It wasn’t perfect, but at night I could look down and roughly gauge my speed.

Also, to help you see where your needle is, in addition to swapping out the bulbs to LED’s would be to paint it gloss white versus the white plastic.

Good luck,
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Re: Half baked idea: fixing the mechanical speedo issues.

Post by VWK75S » Sun Jul 21, 2019 7:19 am

Connected a ground wire to the speedo, made a huge difference in lighting. :)
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Re: Half baked idea: fixing the mechanical speedo issues.

Post by lendrinkard » Sun Jul 21, 2019 7:41 am

I used Wahl's hair clipper oil (a very light machine oil) on the speedo and silicone lube on the cable. The needle is now steady at all speeds.
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Re: Half baked idea: fixing the mechanical speedo issues.

Post by chaos2 » Sun Jul 21, 2019 9:05 am

Mine does not wobble or Fog up, And I put LEDs in it. My main problem has been after about 20,000km it makes a horrible screeching noise and the needle flies off it’s post. I am on my third unit now.
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Re: Half baked idea: fixing the mechanical speedo issues.

Post by Snakeoil » Sun Jul 21, 2019 10:52 am

These are common problems that can affect any mechanical speedo.

1: gauge needle wobble
This could be one of two possible causes. Either the bearing is worn in the speedo or the cable is not running smoothly in the sheath causing the cable to wind up a bit and when it releases, it makes the needle jump. Basically, the speedo is reflecting exactly what the cable is doing. A burr (broken strand) in the cable or incorrect routing with a sharp bend or two could cause the cable to drag on the sheath.

2: incorrect speed reading
This is a simple matter of having it calibrated. Magnetizing or demagnetizing while comparing to a test speedo will solve this problem.

3: can't see the gauge at night
There have been posts on this here. One fix I remember is removing the colored lens that blocks a lot of the light. Mine is poorly lit at night. But I rarely ride at night anymore. I might take a look at mine. Depends on how much of a PITA it is to remove from the bike.

4: gauge fogging up after rain
This is a function of the case design. Sealing it completely is a possible solution. But if you do that, you might want to put an N2 purge in the case before you seal it up. I tend to think that the root cause for this is a poor seal where the lens meets the case, but never bothered to try and prove that. I have rebuilt speedos and always make sure that the lens is sealed to the case. I've never had one fog. And my Ural speedo does not fog, even after a good w@$#ing.
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Re: Half baked idea: fixing the mechanical speedo issues.

Post by rougaroo » Sun Jul 21, 2019 11:30 am

Snake oil said:
2: incorrect speed reading
This is a simple matter of having it calibrated. Magnetizing or demagnetizing while comparing to a test speedo will solve this problem.
That's one of those "easier to say than do" things. The machines that were used to calibrate speedos like these are few and far between and the geezers who know how to use them are even rarer.

The principle behind these speedos is ancient. The cable comes up into an assembly with a magnet, which spins 1:1 with the rotation of the cable. The housing has a bell-shaped metal cup that is attached to a spring, which is attached to the needle. The magnet doesn't touch the cup, but is close enough that the magnetism drags the cup forward.

To adjust the damn thing you have to play with both the distance of the magnet to the cup and the tension on the spring. Like I said, there is a WWII era machine. I found someone who had one and they wanted $280 to calibrate the Ural speedo.

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Last edited by rougaroo on Mon Jul 22, 2019 12:03 am, edited 2 times in total.
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Re: Half baked idea: fixing the mechanical speedo issues.

Post by Snakeoil » Sun Jul 21, 2019 12:07 pm

Yeah, you don't find those guys on every corner anymore, that's for sure. The local guy that used to do mine, charged 1950's prices. He's the one who walked me thru the entire process. I should have offered to buy him out. He had to be pushing 80 at the time. That was back in the mid-80's when I was bringing a '61 Corvette back to life. The tach on that car was also driven in the same manner, with a cable off the generator.

Outfits like California Speedo and others must have the equipment. But to Waz's point, not sure there is enough payback to justify what it would cost for a vintage speedo shop to do the work.

This discussion did peak my curiosity, so, after posting, I went out and pulled my speedo. I can see those colored lenses inside the bulb sockets. Not obvious how one would remove them. And I'm wondering if they do not provide part of the sealing system for the speedo. I did take a modern LED flashlight that is blindingly bright and directed it down the bulb socket and it did make a significant difference.

One thing that I think would help would be to paint the inner bezel ring white on the underside. You cannot see that side with the speedo assembled. The body of the case appears to be painted, but it is more of a gray than a pure white. Painting the inside of the case pure white would probably help as well. But mine is not broken nor fogging, so I'm going to leave it be and maybe try LED bulbs if I can find them with a BA9 base.
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Re: Half baked idea: fixing the mechanical speedo issues.

Post by wooden nickel » Sun Jul 21, 2019 1:26 pm

I bought these on ebay but they have gone up in price since then. https://www.ebay.com/itm/LUYED-2-x-360L ... 2749.l2649
You only need one because they are bright and they are a little too long so you have to tape the socket in place but the lamp sure lights up the speedo.
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Re: Half baked idea: fixing the mechanical speedo issues.

Post by Snakeoil » Sun Jul 21, 2019 2:31 pm

Thanks. I saw your post above. Did not see anything that bright on the Superbright site. Best they had was 96 lumens. But two of those would probably do the trick.
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Rob
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Re: Half baked idea: fixing the mechanical speedo issues.

Post by sKiZo » Sun Jul 21, 2019 6:13 pm

Don't suppose anyone's experimented with an electronic speedo? About a billion of them out there, and I figure at least all of them must be more accurate that the stock unit ...
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