speedo is running to fast?

[kevj]

I have been thinking for some time that my speedo is clocking up the mileage quicker than it should be. I usually ride with a guy on a new Aprllia with digital clocks and there is always some difference in the mileage we think we have done on a ride, with mine always being higher. I went to Cadwell Park at the weekend for the BSB meet and did what I thought was 439 miles and his was saying 389, some 50 miles less. The other person I was riding with also had a reading of about 389 miles!! Does anyone know of how I could find out if it is my speedo is running incorrectly? I obviously don't want my mileage clocking up anymore than its needs to be.

Cheers

kev

[cal]

Looks like you have a duff odometer, but is the speedo reading high as well? Try running alongside a freind at set speeds 20 30 40 50 etc and see if there is a difference, this may be the reason the miles are high. You could probably get it re calibrated but you might be cheaper to get a new one (second hand).

[trixynut]

Maybe just ride slower??



Thats an interesting one. If its not a faulty speedo, it must be a gearing issue somewhere.

So, process of elimination, presuming you have the right size front wheel and tyre (obvious I know but..) and considering there is no 'gearing' in the cable then that can be ruled out, then it could be you have a speedo drive on the bike off another bike with a bigger/smaller wheel (maybe a TDM's, would that fit?)

Otherwise its the speedo, but as the mileometer is gear driven AFAK, then its difficult to see how it could be faulty??

[kevj]

when riding home on moday night i thought i was doing 90 - 100 mph ( i hope there is no coppers reading this) but the others said they were 80 - 85mph!!!

[slow codger]

Just a thought, but you do have a TRX wheel on the bike? and original clocks?

Dave E

[kevj]

yeah original wheels and clocks.

[cal]

Must be the speedo head calibration then if all else is original, but....unless you bought the bike brand new or you have noticed a change in the speedo readings, then the bike may have been giving false readings all the time you have had it,so could be a wrong speedo drive fitted before you got it.
If you know anyone else with a trx you could maybe try swapping the drives (or looking for obvious differences first), this would be a cheap ( free! ) and easy test.
If that is the case then I think you would also be within your rights to ligitamatley (spellchecker!) alter the odometer reading ie divide by 100 and x by 85, Changing the odometer reading can be illegal so I would check up on that first. but if the wrong part has been fitted since you got the bike and you can remember the milage when you got it I personally dont see the problem,

If the speedo drive is correct then it all points to the speedo head being out of calibration ....