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speedo, going going gone???

Posted: Tue Jul 08, 2008 9:57 pm
by jowyvfr
Noticed recently that my speedo needle has been going a bit crazy, bouncing around so its been pretty tricky to guess the speed i'm doing, not good! now it seems to have given up the ghost and doesn't seem to be showing the right speed. doesn't go much above 40 and is real sluggish to even get to that. :twisted: Anyone have any ideas? it still clocks up the miles ok. Thought that 40mph seemed faster recently :o

Re: speedo, going going gone???

Posted: Tue Jul 08, 2008 11:45 pm
by wullvfr
does it notch up the miles just the same or slower..???for example if you do the normal 20 mile journey does the odometer go up by this much?problem could be in the speedo drive somewhere,or new clock needed maybe!!!

Re: speedo, going going gone???

Posted: Wed Jul 09, 2008 12:41 am
by fastdruid
Take it over a known distance to see if the odometer is correct, if it is then the speedo is fscked. If the odometer is out then it's likely to be the drive or cable.

If the speedo is fscked then it is possible that it might just be dirty, unfortunately I don't think the VFR speedo can be taken apart (although I've not got one to look at so I may be wrong).

The speedo works by the cable driving a steel cup, in this at an angle sits a magnet connected to a spring loaded needle. As the 'cup' spins the magnet causes drag and moves the needle, against the spring.

There are three main ways it breaks

1) Distortion caused by accident damage
2) Spring failure
3) crud/dirt/rust causing the needle to stick.

If it is fscked then you've not got a lot to lose by spraying some WD40 in, it might fix it.

Druid

Re: speedo, going going gone???

Posted: Wed Jul 09, 2008 12:42 am
by Cammo
It'll most likely be the small nylon drive that turns the speedo cable on the gearbox side. Take off the small 2-bolt cover and have a look.

They get wrecked pretty easily.

Re: speedo, going going gone???

Posted: Wed Jul 09, 2008 7:52 am
by grandpanot
+1 on comments from stickshift. It is also pretty easy to check. While you have it unbolted if the gear is not buggerred then check that the cable is not binding while you are at it. This would eliminate 2 birds doncha know.

Re: speedo, going going gone???

Posted: Wed Jul 09, 2008 11:10 pm
by jowyvfr
cheers for all that chaps, as soon as it stops pi$$ing down i'll pop the nylon thingy out and have a look, hopefully its this as i'm sure its the easiest and cheapest of all the things that could be wrong. i'll do another post when ive had a butchers, might need some second opinions.