Problem with Speedo instrument flickering

I am thinking on switching my speedo which is in miles, with one in km..
my bike is a 750 Commando Roadster year 1973 (so the speedo is with the green globe and not with the green spot)
anyone can tell the details of the original speedo in km? what is the reference? what is the end scale? 240 kmh?
 
kommando said:
Look at the small lettering at the bottom for a 4 digit number, 1000 is for a 1.25:1 drive ie takes the 800rpm of the rear wheel and increases it to 1000, 1600 is for a 2:1 drive ie 800 to 1600.
Click to expand...
I have seein on the 240 km/h the small lettering is 600 and not 1000 as on the miles/hour.. can you tell if the drive at the wheel is the same?
 
How the speedometer cable is routed from the drive to the gauge can make a difference to how the needle moves.
Check the run of the cable and whenever possible go for straight runs and big curves.
A drill at the rear of the cable on the bike might be helpful.

If DennisMO was asking if you ever would put a drop of oil in the speedometer to lube the bushing (the question was a bit unclear), this can be a good idea. I had a dry bush in a speedometer gauge that responded well to a drop of oil. Normally, this is not required. And it would not typically address needle bounce.
 
Lorenzo said:
I have seein on the 240 km/h the small lettering is 600 and not 1000 as on the miles/hour.. can you tell if the drive at the wheel is the same?
Click to expand...
Best take a picture and post it, that 600 could be 1600 with the 1 missing or an 8 that looks like a 6. 600 was never on a Commando speedometer.
 
Lorenzo said:
I have seein on the 240 km/h the small lettering is 600 and not 1000 as on the miles/hour.. can you tell if the drive at the wheel is the same?
Click to expand...

Yes, it will be the same as I've already mentioned there's only one speedo drive ('70 - '74) one km being aproximately 6/10ths of a mile so 600 revolutions instead of 1000. The only difference in the speedo is the markings on the dial (240 kmh instead of 150 MPH) the needle sweep is the same, however, the odometer gearing is different so the kmh unit clicks around one digit every 600 turns.

"There are 0.62137119 Miles in 1 Kilometer"
 
Last edited:
Stephen,
Thanks!
Did you simply invert the speedometer and let a drop of oil wick in from the speedo drive side??
Dennis
 
I found a speedo which the seller says is NOS.. anyone would suggest this or there’s a risk this may have issues because it has not worked in so many years?
 
Lorenzo said:
I found a speedo which the seller says is NOS.. anyone would suggest this or there’s a risk this may have issues because it has not worked in so many years?
Click to expand...
Are you thinking to ghange speedo to get km/h version or to solve the flickering? Thought you tested the speedo with a drill and found needle was stable? That means instrument is fine and issue is with cable fitment, cable bends or the speedo gear drive.

I run mile per hour speedo in a metric country and just convert in my head. I always recall the TV commercials running back in the 1970's when Canada was switching to metric....The Rule of Six. Take the posted kph speed limit, drop the last digit and multiple by 6. 100 kph: 10 x 6 = 60 mph. 30 kph: 3 x 6= 18 mph (round it up to 20 mph).
 
I am changing the cable of the speedo with a new one: from the instructions I can read the cable should be lubed in advance. Can you tell how to do it? what do you use? are you lubing on both sides: from the speedo side and from the drive? thanks for helping!
 
Ok, I'll bite.

Method 1 (Recommended)
Disconnect the outer cable at the gauge. Pull the inner cable all the way out. Wipe the cable thoroughly on a clean cloth. I use oil on the cloth to clean the inner cable.
Then I apply a light coating of white lithium with my fingers to the inner cable. Reassemble.

Method 2. (If I am feeling lazy)
Disconnect the cable at the gauge end and squirt a small amount of oil past the ferrule into the cable. Gravity will move it down the cable. Reassemble.
 

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