setting idle & chain 'jumping' when riding away - 2005 s2r800

[pmazdan9]

Hopefully that was it, although I'm not convinced that this is what happens in the video I posted! Well, I'll keep an eye on it, if it happens again it's not the chain.

[pmazdan9]

A little update:

My bike passed MOT so I booked it in for valves/tb sync. They'll set the idle for me. I was gonna do tb sync myself, but they won't charge me much more for that when doing valves and I cba to do it as I don't have a garage and it's bloody freezing!

Regarding the chain issue, it's still happening. Not as often but it still does. Once I get the bike back form mechanic, I'll pull the clutch and inspect.

[Duck-Stew]

Just throwing this out there as I don’t think it was mentioned earlier:

Do you have a loose section of chain?  If so, and tension was set at a tight section of chain, when the loose section is near the front sprocket, that could cause your issue.  Chains do not wear evenly.

If you have a rear wheel stand, put the bike on that and roll the chain around checking tension throughout one or more revolutions.  If no stand, just roll the bike.  It may help to mark a point on the chain as the starting point.

[pmazdan9]

Aight, time for an update. I picked my bike up back from the garage on Saturday (after 5 weeks!).

Idle is all sorted. After adjusting valves (needed 5 new shims) it idles at 1500 when cold, and 1250 when warm. These are the figures I've set in the fuel map. It's strange that ECU didn't adjust the rpm before the service, must have been due to bad clearances/tb out of sync. One thing I noticed, it drops to 1250 before dash stops displaying "LOW" (below 50 degrees), map is set to drop when 50 degrees is reached. I'm thinking maybe the ECU doesn't take oil temperature but something different?

Chain seems to be sorted too, although I need to ride it more to confirm. Clutch was the issue I think, in short I took out 1 steel plate and extra washers (I've had 2 on each spring). Not sure if it makes sense but I think the problem is gone.

Thanks for all your help guys!

[Howie]

If things like valve clearance. misfire, synch etc. are far enough off the computer cannot properly compensate.  Good to hear your bike is running properly.

[pmazdan9]

If things like valve clearance. misfire, synch etc. are far enough off the computer cannot properly compensate.  Good to hear your bike is running properly.

It makes sense I guess. Thanks

I found this in service manual:

Normal operation
When the engine is fully warm, the control unit calculates injection time and advance, by comparing the stored map values, in accordance with the RPM and throttle position. The calculated quantity of fuel is fed through injectors in one single sequential delivery to the two cylinders.

Starting
When the ignition switch is turned to ON, the control unit feeds the fuel pump for a few moments to put fuel feed hydraulic circuit under pressure. It receives the throttle position and engine temperature signals. When the engine is started, the ECU receives the engine RPM and timing signals that allow it to proceed with injection and ignition. To facilitate start-up, the basic mixture is made richer in accordance with the engine temperature. During starting, the ignition advance is fixed (0°) until the engine starts. When the engine starts, the control unit takes over the advance control according to the values stored in the mapping and makes necessary corrections according to the air and engine temperatures.

It says engine temperature, is there another sensor other than oil temperetaure sensor?

Also there's one thing that doesn't make sense to me. Manual states the correct idle is 1250 +/- 50. According to the above, ECU controls idle based on values stored in the map. Why on earth does OEM and even DP map have 1000rpm no matter what the temperature is, if correct idle is 1250ish?

[Howie]

There is an ambient temp (and atmospheric pressure) sensor as well as oil temp.  Can't answer about the 1250RPM thing.  There are mistakes in the manual.  Not unique to Ducati. 

[pmazdan9]

Thank you howie, I guess temperature displayed on dash and one in ECU are read from different sensors then. Fair enough about mistakes in the manual. My curiosity is satisfied

I did some googling, here's post from another forum which confirms that:

The atmospheric temperature sensor voltage level tells the computer how much to modify the fuel map injector durations for a given air temperature.

[Speeddog]

Many Ducatis have two engine temp sensors.

Air-coolers have one in the oil screen plug, that goes to the dash.
The sensor in the valve cover is for the ECU.

Desmoquattro Monster engines have two, located in the hot coolant elbows, one for the dash and one for the ECU.

[pmazdan9]

Many Ducatis have two engine temp sensors.

Air-coolers have one in the oil screen plug, that goes to the dash.
The sensor in the valve cover is for the ECU.

Desmoquattro Monster engines have two, located in the hot coolant elbows, one for the dash and one for the ECU.

Thank you Speeddog, that makes sense. Explains why idle drops to 1250 way before dash displays 50+. I might change it in the map again so it warms up a little longer, although I don't have any issues and it's the coldest month of the year here, so not sure if it's worth the hassle.

[ducpainter]

Thank you Speeddog, that makes sense. Explains why idle drops to 1250 way before dash displays 50+. I might change it in the map again so it warms up a little longer, although I don't have any issues and it's the coldest month of the year here, so not sure if it's worth the hassle.

If it ain't broke...

keep fixing it until it is.

[Howie]

If it ain't broke...

keep fixing it until it is.

[pmazdan9]

I guess you're right