Speedo Problem

[dazzler441]

This is my first post so please be gentle. I've got a 2.1 Water cooled T25 hi-top, when I pull away the speedo needle is jumping around all over the place probably +/- 5-7 mph. When I get to over 35-40 it starts moving normally and smoothly. The problem is with speed cameras in 30mph zones in that I have to keep well below, I don't have a sat nav to give me any accurate idea. Also this surely would be an MOT failure and the last one was done in February and it passed.
Is this a speedo or wheel problem or is it something else.
All help greatly appreciated.
Darron

[Oldiebut goodie]

Speedometer is not part of the MoT test. No requirement to have one for a MoT on PLG vehicles.

[Footprint]

Sounds like a dry or snagging cable, speedo jumping around is a common sympton of that.

Failing that the pin on which the needle rotates is worn, which brings the cup too close to the speedo needle and physically moves it, rather then the field inducing its movement. But that's way less likely.

I'd check the cable first for damage, lack of grease and incorrect routing.

[dazzler441]

Thanks for the quick response, I'll take a look at the weekend and let you know.

[big red bus]

Would look at the n/s/f wheel grease cap. Either clip on end of cable will be loose or square hole in cap has worn round which is not turning the cable as it should.

[Ralf85]

Would look at the n/s/f wheel grease cap. Either clip on end of cable will be loose or square hole in cap has worn round which is not turning the cable as it should.

Or it could be a knackered cable. Mine wore out a the speedo end where the cable meets up with the clock.

Patrick

[big red bus]

could be but more common area is the grease cap and clip. 20+ yeas has taken its toll