Rev counter stopped working - solutions???
 

998R wouldn't start after four week lay up. Battery begun to get weak so connected up car battery to get it turning over but it still wouldn't fire.

Followed the advice of a number of threads and assumed fuel had gone orf.. So, discarded fuel in tank and replaced with new optimax (actually 50:50 Optimax: Avgas I had recently mixed for the race bike).

Bike started fine but bugger if the rev counter didn't work. Everything else worked fine (even the red light in the rev counter). In fact the rev needle twitched when the bike started but nothing more.

Help.... any ideas what's gone wrong? I did wonder if I had reversed polarity when connecting the car battery but I think I would have noticed the sparks if I had of done!!!).

Clues by return please... many thanks

Does it work at all? or is it 'lazy' sometimes they dont move until the revs are about 4k,

If so, I have seen it on 998S models, need to check the flywheel rpm sensor on a DDS system, there is a revised clearance on this that a good dealer can do for you, makes the sensor (if the sensor itself hasnt packed up) closer to the pickup.

wilf why would any of that gone wrong if it has just been sat doing nothing ?

In answer to the questions:

Rev needle doesn't move above what I guess to be about 4K revs - i.e. no movement what ever.

In answer to Keefer, the only things to have been changed are the use of a car batter to get it turning over and taking the tank off to empty tank and refill with new fuel. I cannot think how either could bugger up the rev counter

In answer to the questions:

Rev needle doesn't move above what I guess to be about 4K revs - i.e. no movement what ever.

In answer to Keefer, the only things to have been changed are the use of a car batter to get it turning over and taking the tank off to empty tank and refill with new fuel. I cannot think how either could bugger up the rev counter

if i knew that i would be a very rich man!

my guess...

When sensors, electrical connections etc, work ok when you're out riding then not work the next time it fires up. my theory is that heat cycles have something to do with it, runs fine when hot and clearances are different, particularly things like sensors on the motor that get very hot. then when things cool down it triggers the failure/connection break etc.

These things often start with an 'intermitant' fault then totally go, but you may not notice your rev counter packing up for a second or two when your riding, easy to miss.

did you use a loose car battery or with it still on the car?

the ECU's can be damaged by jumping the bike off a running car, pretty unlikely but possible?

if it was a loose battery just hooked up in parallel then it wont have done any damage at all.

Thanks for the replies. I have a feeling it might be one of those ocassions where I end up replacing each relevant component until the problem is solved.

these can be really tricky ones or you may get lucky and get it first time, can only be a few things really.

would be worth getting a good mechanic to put the diagnostic tester on it.

good luck.

The tacho on my 998 stopped working for a while.

I tried every connection I could find with no result.

When the bike went in for a service I asked the dealer to sort it.

When it came back the tacho was fine, and they were sure that all they did was disconnect nan reconnect the various connectors.

Been OK since.

Moral - check all the connectors.

Spin

Had the same thing with the 748, turned out to be a loose earth connection on the battery!

Everything else worked fine except the rev counter which fluctuated badly. I think the loose connection was causing sparking as the battery vibrated in the battery tray while the bike was running. As the Superbike tacho works of a pulse, this was probably over-riding or confusing the tacho and that's why it didn't work. I just tightened up the battery connection and it worked fine. Must have been when I fitted the connectors for the Optimate ... maybe if you removed the battery you have the same problem?

I had the same problem with my 748,the rev counter would work fine then if i stopped say for petrol then started the bike the needle would move and then not work.
I took it to the dealer and the rev counter was replaced,this did not solve the problem bacjk to the dealer and the connections checked and the sub wiring loom replaced again the rev counter failed.
At this point i give up and rode the bike for a season and took it back to the dealers for the mot and a new clutch also asked to check the problem over again,new ecu fitted and the problem solved,this was replaced foc.

For some bizarre reason a dodgy battery/dodgy battery connections have caused a similar problem on my 998.

As the battery on your bike has been flat and/or jump started, I'd check ou the batteru and its connections 1st before getting into replacing component mode.

It takes quite a bit of power to keep the bike running, i.e. Fuel pump, ECU, injectors and so on. For some reason the tachos seem to be very voltage sensitive.

If you have the lights on, switch em off, if that cures it or it "fixes itself" after running the bike at a fast tickover, 2 =3 k revs, for a while, I'd put it down to a low battery.

Ray