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Tachometer Gauge Buzzing at speed

6K views 27 replies 8 participants last post by  Sidecar Bob 
#1 ·
I was riding the other day on my 1980 cx500 deluxe and heard a whining buzzing sound. I stopped the bike and disconnected the tach cable which solved the buzz. The cable continued to spin with no sound coming from it. My question is , is it the cable or the gauge that caused the whining sound . Any body else have this problem? Thanks Jay G
 
#2 ·
I was riding the other day on my 1980 cx500 deluxe and heard a whining buzzing sound. I stopped the bike and disconnected the tach cable which solved the buzz. The cable continued to spin with no sound coming from it. My question is , is it the cable or the gauge that caused the whining sound . Any body else have this problem? Thanks Jay G
Gauge most likely, you can try using a drop or two of sewing machine oil or turbine oil in where the cable goes and see if it fixes it up.
 
#3 ·
You want to get it between the brass and the outside threaded part.
Auto part Metal

Oiling worked for me. Like dbadge said, just a drop or two since it can mess things up, even cloud the glass. I bent a paper clip and stuck it in the hole so I could spin the center piece after putting in the oil.
 
#7 ·
By the way guys is it normal for such an old bike to show like +15 to +20 km/h compared to a radar reading? Just noticed the other day when entering a city that when the radar showed my speed was 50 km/h, my tacho showed about 70 km/h. I’m planning to change the whole front completely during the build, so just asking out of curiosity.
 
#13 ·
My GL500 reads optimistic by 10% relative to the GPS, my 650E about 5%.
 
#14 ·
Some years ago one of the magazines used to radar the bikes during testing for published reports and found that most speedometers were about 5% optimistic. When they started asking the manufacturers about it they were told that it was an industry standard for speedometers to have an accuracy of +5%/-0% because it was felt that a speedometer reading high wouldn't cause problems but one reading low could result in speeding tickets when the speedometer said you were doing the posted limit.

Add in the effects of about 4 decades of aging and wear & tear and it isn't surprising for that to have changed somewhat.
 
#15 ·
Using GPS and those radar signs, Typically, my car and bikes read about 2 or 3 mph under what those measure.
 
#16 ·
FWIW, since they put one of those signs at the edge of our village I've been questioning my speedometers. It almost exactly matches the speedometer of my wife's car but it tells me I'm doing more than 10% faster than the speedometer says on either of my bikes.
Both bikes have the same aftermarket electronic speedometer; I installed the one on Eccles before I retired and the distance to work on the new odometer matched what the original indicated (both bikes' original odos agreed too so I think it is fairly accurate). When I noticed that the speedo didn't match the sign I double checked that I had the correct tire circumference programmed in (I did). I've been wondering if this is something in the software or if something about the shape of a sidecar outfit confuses the sign. I really need to find a chance for us to go for a drive with both car & bike where we can travel at a steady speed for a while and then compare what the speedometers read.....
 
#17 ·
Yeah I know that most speedos show about +10% of the actual speed, on my Honda Civic it the radar shows 50 when speedo shows 55 km/h, just wondered whether it’s a usual fault on older bikes to show more than +15%. Thanks for your help folks, I’ll fix it when I’ll be swapping the fork and wiring.
 
#18 · (Edited)
0r altenatively keep the current speedo and have the only non-turbo that'll show 200km/h on the road :p.....(Joking)

Seriously as long as you are aware of it unlikely an issue and its reading over not under and you have already planned to modify it/replace it..
Between speedo & tacho (rev counter) I always preferred a working tacho/rev counter especially if riding is spirited....good luck
 
#20 ·
Are you going to have a temperature gauge?
 
#22 ·
That's why I asked, as I heard mention of new speedometer and tachometer but not of a temperature gauge.
 
#25 ·
if thinking of a coolant temp gauge rather than a "light"...have a look at Webike (Japan)...there's probably a Yoshimura in keeping with cafe'custom that might appeal....I sourced a daytona aquapova digital from them....but the yoshi with alloy bracket looks nice if you can spend a lil more
 
#26 · (Edited)
Oil temperature is usually only measured in air cooled engines because it is better than not measuring the temperature at all but it won't tell you everything about what is happening inside your 40 year old engine that oil temperature can. A number of engine failures have been reported on this forum over the years that might have been avoided if the coolant temperature gauge had been working.
Honda wouldn't have wasted money on a coolant temperature gauge and a 7V regulator to power it if it wasn't important.

BTW: Please add your location to your profile and your bike's model and model year to your signature so you don't have to tell us every time and we don't have to ask when you forget.
 
#27 ·
Oil temperature is usually only measured in air cooled engines because it is better than not measuring the temperature at all but it won't tell you everything about what is happening inside your 40 year old engine that oil temperature can't.
Bob there is something amiss with your sentence. Were you trying to write that a coolant temperature gauge will tell you about things happening in a 40 year old engine that an oil temperature gauge can't?
 
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