M900 rev counter "sticking" and hesitation

[Xenocide]

Hi Guys,

Popped over to a mates house last night and noticed that the rev counter would sort of get stuck at about 4k then it seemed to count slower than it should do. EG going at about 7k and it would indicate 4.5k.

Coming off a roundabout it cut power for a second but i couldn't make it do it again.

Annoying, it had a problem last year with the oil temp sensor (the one in the front cyl's rocker cover) which had similar symptoms but it's only happened the once. Worth getting louigi to take a look?

I'm supposed to be taking it round europe in the summer. Buggered if im going to if it's doing this.

Any thoughts/ideas/questions gratefully received.

[Xenocide]

2001 M900sie by the way :).

[Martin C]

It sounds like the traditional/inevitable/expected poor wiring connections to me. Try inspecting & cleaning the relevant connectors, and make sure any earths are clean & tight.

Maybe Audi's anticipated imminent purchase of Ducati will result in a more Germanic future approach to the design of wiring for Ducatis (= make it fit for purpose even if it rains a lot).......

And maybe the Germans will put an end to the "factory & parts summer shutdown"......

[Xenocide]

Erk i didn't get a notification.

Ok thank you I will take it all apart and clean 'em up. :).

Something i've noticed though, It happens when it's cold, when it's up to temperature, it's fine.

I might pop it over to louigi at some point and ask him to plug in his box of tricks.

[Sirc]

Is it possible that the dial needle has distorted and is touching the face on the inside? I know it sounds too simple to be true but have known it happen on many occasions. When you said 'stuck' at 4K it made me think it's a possibility.

[Xenocide]

Erm I'n not sure, i'll take a look. One of them (I think the tach) has had a bang at some point and some genius PO has put it back together with some resin crap. Noice.

[Xenocide]

Ok it's been doing it again. I've managed to get a video of her.

http://youtu.be/7mXRMqP_UgM

It's uploading there at the moment so may take a squidge before it start working properly.

I will endevour to pull the harness apart this week as it's wet.

[Edit: Oh it's not sticking on the face either - i checked :)].

[Sirc]

got yah - it's actually like a surge in input isn't it? quite bizarre and i've got no sound suggestions. Apart from checking that the pulse and earth wires are intact I would be looking at borrowing another tacho just to try.

[Xenocide]

The engine misses aswell when it's doing it when it's under load. You can hear it doesn't rev cleanly right at the start of the video.

So I guess my question is: How does the ignition system work on this bike? Does it rely on the clocks to run and because there's soemthing wrong with the clocks it's missing, or, more likely, wherever it picks the revs up from (crank position sensor!?) is dodgy and causing the bike to think it's at the wrong revs and therefore it's displaying what it thinks is correct?

Any ideas anyone?

Thanks for your reply Sirc!

[gary tompkins]

Carbed bikes used to pick up a pulse for revcounter from HT coil. Not sure if this is still the case for EFI monsters. My guess is it get it's signal from the ECU. If so the ECU itself could be the culprit, but I would check for shorts or dodgy wiring in the loom first, and the rev counter itself. I also have a spare stock 900ie ECU here to swap if you suspect that's where fault lies.

[Xenocide]

I've ordered a load of nice mesh wrap for the loom so i'll strip it and replace anything I find then I might be on the phone about your ECU! lol. :)

[Sirc]

I didn't appreciate that it does miss at the same time, that is a useful symptom and it means that the tacho is just being 'faithful'. For cure, as above, you need to check any ignition related circuit - I know it's not as easy as it sounds having been chasing similar on a 996 for almost a year now - I think mine is ECU/chip related also (as i've bl@@dy well changed or replaced everything else now)

[Xenocide]

Buggersticks, yeah that's what I thought.

Ok so what sensors are there I need to check?

Oil temp
RPM signal?
Throttle angle
O2 sensor?!
How does it measure incoming air? There's nothing int he way of the tb's from the airbox is there?


Thank you all for your help :)

Looking at the manual it looks like the rpm pickups are on the flywheel

[Capo]

The fuel injection system does not measure air mass, rather it uses the TPS to give an approximation, air pressure and temperature are constituents of the algorithm.

[utopia]

This is a longshot, and very unlikely to be the cause, but would it be worth temporarily disconnecting your diode mod to the sidestand switch, just in case it is somehow having an unexpected side effect ?

[Sirc]

not 'at home' with your injection system Xeno but certainly TPS or Timing sensor could be responsible for a misfire. I also went through every single multiplug and block connector looking for corrosion - first sign is contacts having a green deposit. Even the long ECU connector is not immune and the 748/916 etc ECU is renowned for taking on water if the 'void' sticker is not applied over the rubber, chip-access bung.

[Xenocide]

The fuel injection system does not measure air mass, rather it uses the TPS to give an approximation, air pressure and temperature are constituents of the algorithm.
Lovely thank you!

This is a longshot, and very unlikely to be the cause, but would it be worth temporarily disconnecting your diode mod to the sidestand switch, just in case it is somehow having an unexpected side effect ?
Good thinking but it's been going on before that so probably not related. Worth a shot though and thank you very much for your input! :)

not 'at home' with your injection system Xeno but certainly TPS or Timing sensor could be responsible for a misfire. I also went through every single multiplug and block connector looking for corrosion - first sign is contacts having a green deposit. Even the long ECU connector is not immune and the 748/916 etc ECU is renowned for taking on water if the 'void' sticker is not applied over the rubber, chip-access bung.

I'll take a look at all of that. What's the best method for cleaning the little buggers? Contact cleaner + small brass wire brush or something more technical?

What's the connector coming off the top of the clutch cover area, one little cable I think. I remember that was frayed a bit and asked louigi to sort it out which he did. Maybe the cable was corroded and we didn't notice?

Again, massive thanks for all your replies. I wish I could be in the garage now instead of at work! Hah.

[Sirc]

re: cleaning connectors, yes it is labour intensive as you don't want to damage anything. I repeatedly flushed with contact cleaner and soaked up/rubbed with Kleenex or equiv. For well adhered deposits I did a bit of scraping with matchsticks/blunt small screwdrivers then re-assembled with silicone grease - anything dielectric will do (vaseline etc)

[Xenocide]

http://img404.imageshack.us/img404/6640/img2494v.jpg (http://imageshack.us/photo/my-images/404/img2494v.jpg/)

Hopefully that fixes it then :). Got a long run tonight so i'll let you know!

If I didn't know better i'd think you guys were coming out and destroying wiring looms to make yourselves correct all the time ;).

[gary tompkins]

Looks like you won't be needing that ECU after all then ;)

[Xenocide]

Yeah hopefully not. We'll see how it goes tonight - taking a run up to the ace to try her out. Nothing like a baptism of fire eh :).

ps: Can you see that picture? It's not showing up for me any more :(

[Xenocide]

Right well it's even more buggered now!!

It boiled the battery on my trip the other day and now barely runs. Was surging etc all the time. Wahh.

The whole loom will be apart and a new reg/rec & battery. Anyone know how to test the reg/reg?

:(

[gary tompkins]

RR unit's probably had it if the batteries been trashed. Looks like your loom needs checking over 100% to find any more damage or shorts. Make sure you clean all the acid off the bike properly, otherwise it'll coninue to eat away and cause more damage. Baking Soda (Bicarbonate of Soda) can be used to neutralize battery acid corrosion, because it is a mild alkali. Be sure to disconnect the battery terminals before cleaning.

[Xenocide]

Thanks. Luckily the breather was attached so it all just went on the floor.. although i should probably check the rear wheel. I've got the new battery all charged up and just got a reg rec off ebay for 20 quid so i'll pop all that on and see if it works, then take the loom apart again.

What's the best way of getting the resin stuff off the crimnped bare terminals in the loom btw? Where the yellow wires join together in the loom was coated in some stuff so it couldn't be soldered very easily.

[utopia]

When investigating overcharging on my bike I came across a "fault finding flow chart for motorcycle charging systems" produced by electrosport (electrex).
Possibly this would be of some use.
Can't do links, but a google should find it.
I believe the reg/rec itself is difficult to test properly. A multimeter with a diode test facility is handy (even my cheap one has this, so not all that uncommon, but many don't).