Speedometer/Odometer issues

The speedometer on my 1972 R 75/5 seems to be acting up as the needle jumps occasionally and doesn't seem to give an accurate speed, and I don't think it is recording the mileage accurately. I haven't had time to disconnect the cable to see if it is broken, or to try lubing it, but I am wondering if anyone has ever connected a GPS speedometer/odometer as a replacement? If GPS is a viable option it may be cheaper and easier than trying to repair the original. Just wanted to throw this out there before I start checking out the original. A replacement cable isn't too expensive, but hate to get one and still find that the speedometer and/or the odometer aren't accurate, so maybe a GPS type would be a better alternative. Any thoughts or suggestions greatly appreciated.

Has this just started happening or is it a long standing issue? I would first look at the cable. Is it routed smoothly from the transmission into the headlight shell and to the bottom of the speedo? You could take off the transmission end and turn the inner cable by hand. Does it seem to hang up or does it turn smoothly? I don't remember which direction is the right way to turn it, but you could hook up a drill and slowly see how the needle responds with that steady input.

With standard cables, oiling them is a last ditch effort. They are usually lined and any extra oil will just end up capturing dirt and making things worse. But you could try and see if that helps. Try something like TriFlow. It's best if the cable is hung vertically so the lube can gravity drain the length of the cable.

I have the same model you are riding. I run a Garmin GPS on it all the time. I appreciate the fuel gauge feature. Running a GPS gives you an accurate speed and other information.

20774 said:

Has this just started happening or is it a long standing issue? I would first look at the cable. Is it routed smoothly from the transmission into the headlight shell and to the bottom of the speedo? You could take off the transmission end and turn the inner cable by hand. Does it seem to hang up or does it turn smoothly? I don't remember which direction is the right way to turn it, but you could hook up a drill and slowly see how the needle responds with that steady input.

With standard cables, oiling them is a last ditch effort. They are usually lined and any extra oil will just end up capturing dirt and making things worse. But you could try and see if that helps. Try something like TriFlow. It's best if the cable is hung vertically so the lube can gravity drain the length of the cable.

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Thanks. I just got the bike last fall and didn't get a lot of miles on it before winter set in, but I did not notice the speedometer jumping. Early winter, I took the handle bars off to get access to the top fork nuts(not sure that is the correct name) as I was installing a Parabellum windshield and 1 of the attachment points was under the top fork nut. I just laid the handlebars down on the cloth covered tank, not thinking about the cables, and I may have did something to the cable, although I didn't see any apparent kinking. The needle flutter started this spring, after re-installing the handle bars, so I believe that I must have done something to cause this. It seemed to correct itself after a few runs on the bike and seemed quite steady until a few runs recently. Yesterday the bike was starving for fuel shortly after I got on the highway, and I had to switch it to reserve to keep it running. Having filled it about 120 miles ago, it seemed strange to be running out of gas this soon, so I began to think that the odometer must be off too. I also noticed that the bike seemed to be going faster than what was registering on the speedometer, and at 70 it seemed I was going much faster than 70. I don't have a lot of miles on this bike since I got it, and I am coming off a 2014 RT, so it is hard to compare "ride feels". It has been 50 years since I owned another 1972 /5 so my recall of how fast 60 feels on this bike is a bit sketchy. I will do as you suggest re the cable, but will stay away from lubes until I find out more.

bluehole said:

I have the same model you are riding. I run a Garmin GPS on it all the time. I appreciate the fuel gauge feature. Running a GPS gives you an accurate speed and a number of other information.

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Thanks, that helps. Could you advise more about the Garmin you are using...my tech knowledge/skills are limited. I was looking at some types of GPS units on line, but not Garmin, and they weren't all that expensive so no not sure if they are any good or not. I am going to research some options as I think that this is what I will end up doing as even if I can get the speedometer/odometer working again, it is a pain to have to record mileage, calculate the miles travelled, and how many left. I carry a 5 liter container of gas in one saddle bag as a backup, but having a fuel gauge option would be great, even though my non-techy brain can't quite figure out how that would work.

Thanks again

I am with you. My skills are limited too. I am running a Garmin Zumo 395 on my R75/5. I have had it on the motorcycle for years so there may be a newer version available. I think they run in $300-$400 range. Not cheap, but, at least for me, very much worth it. The unit has been reliable...no problems. If fixing/replacing the cable does not work out, this may be a good option for you. My speedometer does flutter a bit at certain speeds, but the odometer is pretty accurate. Another option might be for you to mount your cell phone and use that as a speedometer, but that does not address the fuel gauge need. I have heard people say running a cell phone on a motorcycle is not a good idea because the environment is rough on a cell phone. I use a GPS so I can't speak to that issue.

Send your speedo top Terry Vrla in Hillsboro Oregon, He will calibrate it to your final drive, and it is accurate within 2 miles per hour. terryvrla@hotmail.com

If you send your speedometer out for repair, I recommend Overseas Speedometer or Palo Alto.

I put a GPS/speedometer app on my iphone and going to see how it compares to the dials, then decide what to do about them. Thanks to all for the replies. I probably wouldn't send the unit away as I am in Canada and sending to USA would be difficult and probably expensive.

2wheeljunkie said:

I put a GPS/speedometer app on my iphone and going to see how it compares to the dials, then decide what to do about them. Thanks to all for the replies. I probably wouldn't send the unit away as I am in Canada and sending to USA would be difficult and probably expensive.

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Ok, I tried the bike with the GPS app on my phone and it doesn't look like the cable is broken or not working, but the speed is showing 5-8 mph lower than the GPS. This was quite consistent and at speeds from 30-50 mph it was right around 5-6 mph below, at 60mph it was consistently 6-7 mph low, at 70mph it was between 6-8 mph low. It was also 1-2 mph closer to the GPS reading before the bike warmed up, not sure why. The GPS showed 38 miles travelled, and the odometer was within 39-42 miles,....I forget exactly what was on the bike, and don't want to walk down to check. So, I either didn't have the bike filled as full as I thought it was, or I wrote the mileage down incorrectly, either way I had to go to reserve before I thought I should have. And my "feel" for the speed I was travelling was definitely off. I had thought that I was going faster than what the bike was showing, but according to the GPS, I was going slower. I guess this makes sense as the RT had a lot better wind protection, a more "enclosed" feel, and never really saw the pavement rushing by like I do on the /5.

The GPS reviews all said it was a good app, and very accurate, within 1- 1.2 miles compared to measured miles, speedometers, and radar. I will try it a few more times, maybe get another well rated app to compare, but it looks like the speedometer just needs some recalibration. Also, the needle didn't seem to be fluttering or jumping around, maybe 1 or 2 times between 65-75 when I turned the throttle down, or that could have been just my eyes seeing the needle move down as I was on a bit of a twisty road and was watching it as well. At least with the speedometer registering below the actual speed I shouldn't have to worry about getting a speeding ticket. I did wonder a few times at vehicles pulling out and roaring past me when I thought I was following the 45 speed zone, and I was actually only doing 39....hope they never heard me raging at their impatience.

I do not think this is an unusual situation. Many motorcycle speedometers read speed optimistically. The odometer may not be off by much. It will be interesting to see what the comparison is between the GPS and odometer as you put some miles on the /5. Which tank do you have? I have the small tank so I start looking for gas around 130-140 miles.

At some point, European manufacturers faced significant fines if their speedos under reported speeds (leaving drivers open to tickets when they thought they were obeying the posted limits). As such, all bikes back in the day were pessimistic by 10% or so. And putting something other than the stock tires will affect the reading.

When I've checked by GPS, modern bikes seem more accurate.

bluehole said:

I do not think this is an unusual situation. Many motorcycle speedometers read speed optimistically. The odometer may not be off by much. It will be interesting to see what the comparison is between the GPS and odometer as you put some miles on the /5. Which tank do you have? I have the small tank so I start looking for gas around 130-140 miles.

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I went on another short run today before getting rained out; and I used another GPS app. It was exactly the same as the other one and the speedometer was indicating 5-6 MPH below the GPS. I rechecked the mileage from the odemeter the other day, and it was within 1 or 2 tenths of the GPS; hard to be exact as the odometer doesn't show the 10th's.
The GPS app I used today was the same as the odometer, so I am confident that the mileage is recording correctly. I did notice that the speedometer needle jumped when it passed the 70 mph mark...it shot all the way up to 90, then fluttered back to the 70 mark and it did this every time I accelerated to 70+. Not sure why, but I will just take that as a warning to keep the MPH down. I can live with the slight differences, it will just keep me from speeding.

I have the small tank (toaster) as well and I guess that I will have to do some recalculations as to expected mileage as I believe your 130-140 range is about when mine started to die and ended up going to reserve. When I filled it(right to the brim) it took 14.7 Litres. Full tank is about 17 Litres (4.5 US gallons), and I believe the reserve is around 2 Litres, so I had about 2.3 Litres left in the tank, which may have taken me another 25-30 miles. I also carry a 5 L can in the saddle bag, just in case. This little exercise with the GPS has has intrigued me now with modern technology, and I will keep the app on the phone and use it as it is easy to put on the tank bag. I know back in the 70's I put on lots of miles on the /5 and the /6, and never ran out, but it was a natural thing back then. Having the computer on the RT's tell me exactly how many miles I could go with what was left in the tank sure spoiled me, and a few times I sure pushed it to the limit, hoping that computer was right....and it always was. I guess it's time to reset my brain to the 70's again.

ccolwell said:

At some point, European manufacturers faced significant fines if their speedos under reported speeds (leaving drivers open to tickets when they thought they were obeying the posted limits). As such, all bikes back in the day were pessimistic by 10% or so. And putting something other than the stock tires will affect the reading.

When I've checked by GPS, modern bikes seem more accurate.

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That's what I just found out....I guess back then we didn't have anything to compare the old technology with so we just accepted what we had as state of the art.

Sounds like you are in good shape. If you can live with the way things are now you can enjoy the riding season and deal with the fluttering later...if you chose to do so. There are a variety of fuel gauge apps available. I picked this one out randomly. On the Garmin, you enter your expected fuel range once and the GPS counts down the miles as you travel. You can have a warning come on at a specific number of miles. In my case, the range is set for 160 miles with a warning to come on 30 miles miles from "empty". The Garmin simply display the numbers...no illustrative gas gauge. I think these cell phone apps work similarly. Could be a a way to solve your fuel gauge problem.

https://play.google.com/store/apps/details?id=com.kworthstudios.fuelgauge&hl=en_US&gl=US

bluehole said:

Sounds like you are in good shape. If you can live with the way things are now you can enjoy the riding season and deal with the fluttering later...if you chose to do so. There are a variety of fuel gauge apps available. I picked this one out randomly. On the Garmin, you enter your expected fuel range once and the GPS counts down the miles as you travel. You can have a warning come on at a specific number of miles. In my case, the range is set for 160 miles with a warning to come on 30 miles miles from "empty". The Garmin simply display the numbers...no illustrative gas gauge. I think these cell phone apps work similarly. Could be a a way to solve your fuel gauge problem.

https://play.google.com/store/apps/details?id=com.kworthstudios.fuelgauge&hl=en_US&gl=US

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Thanks, will check it out. I have an iphone so can't use the google app, but there must be something that works with ios.