Smiths digital speedo accuracy

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After reading all of this, I am pretty glad I just had my clocks refurbished instead. They are dead steady now.

Just the annoying cables...
 
Yeah - when I decided to buy the E-Smiths, it wasn't due to anything wrong with my OEM gauges - they both worked fine. I had recently seen a Norton in a Pub parking lot that the owner was pulling the speedo drive gear off that had become red hot/seized up. I thought, "I don't want that to happen so I'll buy those new E-SMiths.

Usually I exhibit more common sense than that. My speedo drive gear was working perfectly - I maintained it as per the routine service - a bit of grease. So there was NO functional reason to make the change. I forgot to ask him the critical simple question..."Do you ever lubricate the drive gear?" I discovered much later through a friend that the answer was, "No," but I was struck by the "upgrade" fever at the moment. :(

Ironically, I'm using the standard sensor that comes with the E-smiths which requires the OEM speedo drive gear! I never purchased the sensors that would eliminate it. SO...I spent several hundred bucks on the E-smiths and kept the ONE ITEM that I specifically wanted to eliminate. Yep, I still use the original drive gear with the new Speedo! Go figure...
 
I have been running an Acewell unit mounted between the handlebar clamps for 5+ years, avoiding the cost and hassle of rebuilding the stock clocks, drives and cables. Speedo sensor mounted on the front fork, magnet epoxied to the wheel. Tach signal taken from one of the spark plug leads. The whole setup is mediocre at best. Tach is a digital bar type display, it's erratic and I never trusted it. The speedometer is ok so I have some idea on mileage and it has a trip function. I assumed at some point I would get the Smith's E gauges, but held off. I really wanted to have stock looking gauges in the factory cups. I read this thread last week and checked out the Legendary Motorcycle GPS gauges that MichaelB linked above. Did some more reading on this forum and decided to pull the trigger on the GPS Speedo and Tach. I received them yesterday. Dead simple to wire, however, I didn't wire it for the hot start function. Doing so requires a relay, which is no big deal and I may add it later. I was able to pack all of the excess wires into the gauge cups rather than stuffing more wiring under the tank. The tach connects to one of the coils and a simple process is used to set the correct pulses per revolution using a supplied push button that plugs into the back of the gauge. I removed the push button when done setting the tach. The GPS pickup has a fairly strong magnet. I stuck it to the top of the fork clamp for now.
Two minor items. The website says the gauges are supplied with new rubber caps for the stock cups, none were included. I used the old caps from the stock gauges. The website photos also show a nice rubber capped button on the speedo face for cycling through the digital options. The speedo I received did not have a button in the face. Instead a small momentary push button was supplied that plugs into the back of the speedo. I ended up mounting the button in the headlight shell. It replaces the green indicator light that was not in use. There's just enough wire length to comfortably do this. Both are very minor items and wouldn't have stopped me from purchasing the gauges had I know about it. All I had time to do last night was get them wired and set the tach pulses, didn't start the bike. Inside the garage I couldn't get a GPS signal, so nothing else was done with that. Doing a little digging in the Speedhut FAQ pages, I found that you can set the odometer to match the current mileage on the bike. I will be trying this when I get a chance.
The gauges are fairly loose in the cups. They will be mounted with clear silicone. I won't stick them in until I've tested everything. They look close enough to the stock gauges for me. I very rarely ride at night, but the lighting is very nice. I'll be out of town most of the weekend, but hope to do some testing Sunday afternoon. I'll update here if anyone is interested.
 
there have been some changes from when the pics were put on there site. I do the hot start option when i install them. if you are not after perfect gauge cups i give the owner the option of mounting the reset stepper button in the side of the cup and you can use 2 small set screws in the cups to hold them in place. looks like i need to have them update there web site.
 
Bill - I read a post of yours from some years ago saying that if the hot start is wired and the bike will sit for extended periods of time a switch should be installed to turn off the hot start. Without the hot start, how long will it take to acquire the GPS signal? Just trying to justify adding the switch and relay.
Also, there was a resistor in the bag with the tach. I couldn't find anything in the instructions regarding this resistor and did not install it. What am I missing?
 
not sure what the resistor is for. as to the switch if you call extended period a month or more than than i would put it on a battery tender anyway so i would forget the switch. with the hot start wired up after the first start it will take just a few seconds to reacquire it happens fast enough that it is up about as soon as i get it started and start to move. this hot start will only last for a couple of hours but it is nice when you are out and stop for gas or lunch.
 
Brly, I have the gps transponder placed in with the magnet on the inside of the head light ears .doesn´t move. Nicely hidden and works perfectly.
 
GPS satellites transmit information about their location (current and predicted), timing and "health" via what is known as ephemeris data. This data is used by the GPS receivers to estimate location relative to the satellites and thus position on earth.

A "hot start" type function uses an extended version of the ephemeris data tables that is valid ~4 hours and then your GPS needs to download the data tabbnle again from the satellite. The extension comes as an additional per unit cost from the chip set manufacturer and from GPS map data providers (for sat navs).

Depending on your location, weather and overhead obstructions the data shouildnt take longer than 4-5 mins to download. At least that was my experience in Auckland when I was building GPS units a number of years ago, and NZ is in a relatively poor (oblique) satellite reception position.

Edit, after a quick search online I see this has changed a bit in the last 10 years. Ephemeris data is considered good for up to 30 days now.
 
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Good info on Legandary stuff guys. I’m building a custom and thinking of their big 4” single combo.
A picture and dimensions of the GPS pick up would be nice.
 
Thanks for the replies. Didn't have much time yesterday. I pushed it outside and turned them on. I didn't time it, but it was less than 2 minutes to acquire the GPS signal. Ran through all of the functions and set the odometer. I'm picking up a relay and inline fuse holder today, should have the hot start wired up tonight. Once the wiring is done I can put the tank back on and start it up. Very happy so far!
MichaelB - Bill posted a picture at the top of page 3 here: https://www.accessnorton.com/NortonCommando/gps-speedo-and-electronic-tach-green-globe.14342/
I can get some measurements on the pickup.
 
Triton Thrasher said:
It was from EBay. It doesn’t display a brand. It was listed as a 160mph 85mm GPS speedometer. The listing has gone now, but there are plenty similar. They appear to have 120 mph ones now, which is more sensible then 160 mph.

https://www.ebay.co.uk/itm/303362348044
Click to expand...

I recently noticed it seemed to under-read, compared to roadside “your speed” warning signs.

I think it’s mostly a parallax effect, because the needle is held up a bit proud of the printed face.
 
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