Sticking/jumping Rev counter

[paulbaker1954]

My rev counter gets to 5 and sticks then jumps to 6 and above 6 is a bit "sticky"

The bike is just on the road after many years lay up

Is this likely to diminish with use, will a liberal squirt of wd40 up the drive hole help or do I need to bite the bullet and pull it apart

[kent400]

Check the cable first,  maybe isn't revolving freely. If you have a variable speed power drill with a reverse facility remove the tacho, find something that will fit in the square drive and stick that in the chuck. Run it up slowly with the reverse facility engaged and see how the tacho behaves.

You could also disconnect the cable at the engine end, straiten the cable and run it up with the power drill. A straight cable might revolve freely but one that isn't when fitted might not.

[Harold 400/4]

Had exactly this problem on my 400/4, 1977. New cable sorted it.

[paulbaker1954]

Ok this gets weirder I also noticed that this doesn't happen when you Rev the bike in neutral Rev counter is smooth all the way so sure it's not the cable

This is only happening on the road, anyone any ideas

[mike the bike]

At speed,  the oncoming airflow ia acting on the clock, pushing it back slightly.   I dunno, it may be a factor.

[paulbaker1954]

Ordered a new cable - lets see.............

[ST1100]

Ordered a new cable - lets see.............

Next item would be the cam sided worm-gear/mechanism...