speedo needle

Hi I have a 1973 850 was out for a ride today ,and the speedo needle started to bounce all around when in contact with bumps on the road then would sit on the marked MPH number all good to the Next load of bumps.
is this the gage or the cable.

Have a look at the drive end of the cable.

Greg

I would say it’s probably the cable. Check that it is routed correctly on the bike. The cable should be running on the right 1" down tube and inside of the frame cross brace directly under the engine. You might need to change the angle of the Speedo gearbox slightly and keep the cable loose up against the frame and swing arm so it can float. In other words don't zip tie or tape it up too much. It might very well have been pulled apart or it’s about to at the speedo gearbox nut/cable. I would be looking hard at that area.
Cheers,
Thomas
CNN

Hi thanks for your comments it so happens that I just touch up some stone chips with new paint, then I cable tied speedo cable back to frame, as I am new to the ways of the Norton, and did not even think to note how cable was placed. will go out and have another go.
cheers Mike

Cable. Don't forget to undo the whole thing ,pull cable totally out of sheath ,clean it then re-insert with fresh gease. Leave the protruding instrument end grease free.

CanukNortonNut said:

I would say it’s probably the cable. Check that it is routed correctly on the bike. The cable should be running on the right 1" down tube and inside of the frame cross brace directly under the engine. You might need to change the angle of the Speedo gearbox slightly and keep the cable loose up against the frame and swing arm so it can float. In other words don't zip tie or tape it up too much. It might very well have been pulled apart or it’s about to at the speedo gearbox nut/cable. I would be looking hard at that area.
Cheers,
Thomas
CNN

Click to expand...

I put on a new cable after the bike had been torn down for months and now you have me thinking. I am not at the bike now so this might be really stupid but I will ask anyway.

So it goes on top of the front cross member (between the engine case and cross member) and does it go over or under the swing arm pivot ??

Marc

Norton factory routed stuff as best the assembler felt like just then, so its up to you to route best ya can and each way has some compromise. Do note besides a binding cable jerking in needle it jerks some more life out the wimpy Spdo drive too. I give priority to the least stressed entry angle into the clocks.

lomaxcm said:

I put on a new cable after the bike had been torn down for months and now you have me thinking. I am not at the bike now so this might be really stupid but I will ask anyway.

So it goes on top of the front cross member (between the engine case and cross member) and does it go over or under the swing arm pivot ??

Marc

Click to expand...

Marc
Yes I place the cable on the inside edge of the down tube loose under the engine but over the cross tube or support. It then goes on the inside edge of the tube and when it gets close to the swing arm pivot it runs on the underside but here I have a real loose tie wrap. Only one tie on the swing arm close to the frame. Enough to put your finger or thumb through the loop.
The cable runs on the underside of the swing arm pivot. The speedo gearbox cable entry is at the bottom facing obviously forward. Now it is here you may need to change the angle slightly to suit. I use John Bull type cable wraps for the frame tube run and use a loose fit heavy black zip tie on the swing arm.
Is this absolutely correct? Who knows but it works for me.
Cheers,
Thomas
CNN

Thanks so very much Thomas.

Marc

Are your headlight brackets on correctly. Adjustment slots parallel to the ground, Mine are reversed so they angle upward making the speedo end cable routing tight. My speedo does the same thing steady and then bouncing, then back at the same speed and gear. My cable is routed as Canuck describes. Part of the winter project to flip and hopefully minimize bounce.

Smoothest routing that works,never bends or kinks, forget about how it "should" be. Instrument -end dry.