MoTeC Global Forum

I am in the process of converting Ducati 916 to Motec M84.
I have been able to connect all sensors & generate fuel pulse & spark through testing outputs.
The Ref/Sync capture with the plugs removed appears as expected &motor syncs.
Flywheel has 4 equally spaced tabs aligning with TDC for the two cylinders.
Cam/Sync sensor is at 65deg ATDC of Cylinder #1. Its a 90deg Vtwin with a 270deg firing order.

However with the plugs installed my ref sync capture changes completely.
I get a bunch of errors & the RPM jumps about the place as the motor can no longer sync.

I don't think it is interference as this occurs even with the Relay powering spark & injectors removed, also ignition amp was removed.
I think it is compression related & that the uneven cranking speed is somehow messing with the ref/sync.
I believe the sensors are ok as the engine did start on the original P8 computer.
Also the starter is a known weak point with these motors. These captures were done with a booster pack to eliminate an low voltage issues.
Not sure where to go from here.

As a side issue have calibrations been done on,
Marelli BAE 850AK coils & Webber IW724 injectors.

Any help would be appreciated.
Thanks,
Michael

Capture with plugs in.

Hi Michael

From memory only the 916SP came with the two sensors for ref and sync.
I have used them a long time ago with M4s, and they did work, but we had more success by adding an extra 4 teeth to make them 8 and 1.
Seems strange there is extra sync pulses once the spark plugs are fitted every 4 ref pulses instead of correctly every 8 before, and it appears to occur coming up to TDC (slow down and therefore less peak to peak voltage on the ref sensor),
Is the sync sensor is the slot milled into the gear or is it a raised tooth, I cannot remember?
Can you see the alignment of the sync sensor to the gear?

Btw a M84 does not have 3d individual cylinder tuning, so tuning both cylinders will not be possible.

Thanks for the tip on the flywheel teeth.
You are correct, it is the earlier model with the two sensors.
I think what is happening is the starter clutch is slipping & the motor is getting caught in the V of the two compression pulses & rocking back & forth.
There are no indents in any of the teeth, the sync tooth is a raised tooth on an intermediate gear running at half crank speed.
Yes with the M84 I am hoping to get a reasonable tune with bank & individual injector trims for the second cylinder,
This is a bit of a learning exercise.
I will try & get my hands on a roller starter as it may be a bit hard to try & bump start the bike while trying to hang onto the laptop at the same time.
Regards,
Michael

If the sprag clutch is slipping now, it will not last much longer. I know that from a lot of experience on the later models which use a different crank trigger which were prone to kicking back and wear the starter clutch.

No surprise, but it does not make sense. The sync is showing a pulse when the sync tooth is 180 degrees away. There should be nothing but air there. With it happening near top dead centre on both Compression and Exhaust stroke, very strange.

Can you post up your config file, also how is the ref and sync sensors wired.

Can you do a capture with spark plugs out, and also one with both plugs in tight.

Glen

PS you are not able to do the individual cylinder tuning required with a M84, they do not have that function.

Thanks Glen,
What you explained with the sprag clutch sounds exactly like what it is doing. If I hold the starter too long you can hear the starter motor free spin.
The first ref/sync capture I posted is with the plugs out.
The second was with the plugs in finger tight, but relay & igniter pulled out.
The Ref pins on the flywheel are every 90 deg, the Sync is at 65 deg ATDC #1 therefor should be 205 deg BTDC cyl #2.
I went through the loom item by item to try & eliminate any noise & could not effect a change. It was down to screwing the plugs in.
Ref & Sync are wired with screened pairs. I ran them on the the LHS of the bike with the main loom on the RHS. ECU is mounted in front of the headstock.
I am aware of the M84's limitations in regards to individual cylinder tuning, the original Marelli P8 ran in a similar fashion. I am hoping to come to a reasonable compromise with bank & injector trims.
Otherwise one of the new M130 GP Lite ECU's may be a possibility.
Please see attached setup so far.
Thanks,
Michael

Hi Micheal,

Your wiring sounds ok.
Can you do a ref/sync capture with the spark plugs fully tight, there should be big change in the cranking speed at TDC of both cylinders for an engine like that.
I do not have a capture of the 916SP trigger system except where it was converted to hall effect, but attached is the 48-2 setup of other Ducatis. You can see the big change in speed clearly, and why they are so hard to get to sync up.
I did not see anything incorrect in the config file.

FYI M130 Lite has the same limitations on individual cylinder trims as M84, so you would need GPR or M400. From my experience the way a Ducati starts on an M1 is so much better that a hundred series, so i would not recommend the M400.

Thanks Glen,
I appreciate you having a look. I may be a day or two in posting an update to sync.
Starter sprag is being replaced to eliminate that issue & will put fresh belts in at the same time.
Spent the day playing with M1 tune & a few sample packages, I think to get individual cylinder mapping & hi-lo injection requires the GPR license. However the more compact & additional logging makes it attractive.
Will report back asap.
Regards,
Michael

If you are looking at M1 then look at GPR Motorcycle, it is a very good package.

I fitted this package to a 748R that had been modified and fitted with 1199 DBW throttle bodies, it made a very nice bike to ride. I fitted an M4 to it nearly 15 years ago, so it was a massive improvement in how it started and ran with the modernisation.

Thanks,
I wasn't thinking about DBW but now will consider it.
Initial plan was to tune it as is, then look at some bored out throttle bodies & relocating the second injector to the 749R shower position, maybe with some extra comp. The cases seem to have longevity issues on these if pushed too far.