Speedo reading again, only different

[Toooldtodie]

Here we go again!
Setting:
K5 replaced speedo rotor
Speedo now occasionally reads 12mph at standstill (a movement of the bike back and forth gets it back to zero)
On the move it is slow to start registering speed then jumps to twice or more the actual speed

Am I looking at a knackered speedo drive? Bad electrical connections? Or faulty speed sensor? All or some of the above?

Not sure where to start, any help very gratefully received, especially as racking up the miles exponentially!

[Toooldtodie]

Update:
Reads 20mph+ at 30mph
Reads 35mph+ at 70mph (obviously the fastest I EVER go)
Odo reading 26 miles for a 20 mile journey

Please help guys! My wallet is in danger of being plundered! Again, and my children were expecting an ice cream this summer.

[Geodude]

Sorry im a curvy owner so not much help but lm sure a search for green connector problems might shed some light oh and maybe check battery terminalsare not loose. HTH

[andrewsmith]

Originally Posted by Geodude

Sorry im a curvy owner so not much help but lm sure a search for green connector problems might shed some light oh and maybe check battery terminalsare not loose. HTH

This or its the sender

Sent from my D2303 using Tapatalk

[Bibio]

take front wheel off and inspect the rotor, if damaged replace. when putting front wheel back on remember to engage the lugs on the rotor in the cutouts in the hub.
lift petrol tank and find the speedo sender connector wire connector. pull apart and inspect for burnt/corroded wire connectors. if found replace the connector.

[Toooldtodie]

Thanks guys.
Having had to bypass both connectors to keep the headlights working I suspect you're all right, and I know where this one is (it's got a pink wire). I had the mangled rotor replaced by a competent mechanic as I lack equipment (read skill). But at £45/hr I want to armed with some info before I go back and throw myself at the tender mercies of said mechanic (now I know why they wear those latex gloves and it's got 'nowt to do with keeping OIL off their hands!).

[Toooldtodie]

Originally Posted by Bibio

lift petrol tank and find the speedo sender connector wire connector. pull apart and inspect for burnt/corroded wire connectors. if found replace the connector.

Thanks Lance, checked out the wiring/connectors and it seems to be the only thing left on the bike that looked as it did when it came out of the factory... which got me thinking... maybe the sensor has always been duff? Or could it be the sender?
Bike is in danger of clocking up more miles than that Pluto probe, speedo reading 105mph at 70, so indicated speed getting closer to that probe too. Do I need to check current and voltage going in and coming out or is there an answer out there that doesn't involve me swearing loudly and repeatedly and thereby setting a bad example to my children (again)?
Many thanks in advance...

[Bibio]

this sounds like you actually have the wrong speedo sensor or rotor. if all connections and inner rotor are sound then its got to be the sensor.

have you actually taken the wheel off to check that the inner rotor is spinning freely and all the tabs are there?

have you replaced the inner rotor or sensor before?

[Bibio]

here is the test as per service book


early bikes should see 4 x the 6v and later ones 8 x the 6v pulses on a full wheel revolution. instead of the 4x 1.5v you can use a single 6v

[Toooldtodie]

Thanks Bibio, the rotor is new but could the old one disintegrating possibly have damaged the sender unit? Could the instrument cluster bit (stop me if I get too technical) be knackered and is mis-reading the info sent to it?
Multimeter, swear box and time needed I see.
Does the resistor fail do you know? That could give a false reading.
Aagh! Will investigate in some sort of logical way and post results so I can hopefully help others in a similar situation.