I have K100RT (1987) which came with a faulty speedo and rev-counter. The speedo didn't work at all so I replaced the Impulse transmitter which fixed the speed issue. However, I am not sure how to go about fixing the rev counter. It works to an extend but reads about 1500 rpm too low. The needle seems to be way below the 'zero' when the bike off and sits at about the 'zero' level when the bike is running at idle. I wondered if anyone had a similar issue and whether I should be taking the instrument panel out and adjusting the needle or whether the issue may be at the pickup from the engine (not sure where the rev-counter picks up its signal.  Any help greatly appreciated.

Hello!

The rev-counter gets it's signal from the ignition coils.
You could do some electric maintenance, DeoxIT as a example.


1.) ignition coils connection
2.) take of the speedo and clean the connection on the rear side
3.) have a look inside the speedo
http://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/flakyspeedo/flakyspeedo.htm


Cheers

Hello Rob, it sounds as though the rev counter needle has moved on it's shaft. It's just a push fit so it should be easy enough to pull it of the shaft and reposition it at zero.

Good luck,
Paul.

sidecar paul wrote:Hello Rob, it sounds as though the rev counter needle has moved on it's shaft. It's just a push fit so it should be easy enough to pull it of the shaft and reposition it at zero.

Good luck,
Paul.

Totally agree with Paul. It is easy to get the needle in the wrong place when replacing it after having the dial off.

Thanks for the replies and the great link. Sounds like its worth cleaning up the electrics and sorting out the needle position. I will crack on with that at the weekend. 

While I have the instrument cluster off, I wondered if it was possible to get a new gear indicator and clock display at the same time. Can these be purchased and fitted separately or are they part of the main circuit?

they are just a pcb that pushes onto pins in the instrument cluster and fixed with a couple of screws

motoworks have them as second hand parts on their website availability is always variable  

as usual pins that are connected to sockets on anything that vibrates needs special care with the contacts between the 2 parts

look up "deoxit " ...and have a good look whilst you have it apart for wear spots between the contacts
good luck

Hello!

Maybe this link helps.

Cheers

Fix A Flaky K Bike Speedometer

Thanks Chocolate, I just drilled back up that link you provided to the top level. There are a lot of really helpful maintenance guides there. Really useful!

Yes Rob, indeed, nice page.

Cheers

Charlie99, thanks for the pointer on the clock and gear indicator. The price is quite steep so I have only ordered the gear indicator as that is totally shot but the clock is not in too bad a shape so I am hoping cleaning up some connectors will get it fully working. If not, I might live with that for a while 

there are a few interesting posts about the clock right here in the forum

use the search feature ??

cheers

Thanks to all for the advice and help as I managed to reset the rev counter and although I don't know if its very accurate, it is definitely better than it was. I also managed to replace the gear indicator circuit and was amazed that it worked straight off!.  While I was working on the bike I also replace the clutch push rod rubber boot as the old one had a hole in it and was leaking oil. I have to say, there was allot of cursing required to get fit the new boot!

good to hear

ride well