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Discussion Starter #1 (Edited)
916 starting issues and the like (grinding!!, misfires, and stalls, oh my)

Hello all!! I have my suspicions but would like to hear your thoughts on my issues.

Background : First year (94/95) Ducati 916, pretty much stock with the exception of windshield and taillights. I am running LED rear lights + integrated signals to help reduce power load on elec system. Recently I went to all electrical connectors, cleaned them and then added dielectric grease. I replaced the heavy electrical mains (battery[-] to ground ; battery[+] to solenoid ; solenoid to starter) with some very heavy wire; 4 gauge fine stranded with large copper ends and soldered and sealed connections.

Issue 1 : When I hit the start button, sometimes the engine pops then the starter motor just spins, some times the engine turns over a few times and then screeches/grinds, sometimes it just grinds all the time.... very loud and horrible sounding. it usually takes multiple attempts to get it started, and is very embarrassing and probably bad. This is the most pressing issue!!

Issue 2 : When the engine has warmed up, sometimes the engine seems to miss a cylinder-ignition/pre-detonate and the engine sounds like it hickups or sneezes. very dangerous on a slow turn

Issue 3 : When I got the bike the radiator fan fuse was blown. I just realized that recently and when I replaced it, it cause the bike to die intermittently in town after it was warmed up. battery is good (and on battery tender each night), rectifier seems to be working but I will test that tomorrow and report back whether or not 14v when running.

I assume they aren't related but I figured I would throw them all out there to help diagnose it! like I said, I have my suspicions but dont want to "taint" the responses by mentioning them.
:)
THANKS IN ADVANCE!!!!!!!!!!!!!!!!!!!!!
 

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Could be the Nut at the center of the Stator needs to be checked. These early 916's needed to have this Nut retorqued.
 

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Discussion Starter #3
Thanks for the idea! Once I can depend on my beater-bike again I am going to drain the fluids, pull the side, and get down to brass tax. I will definately be checking the torque on that. I wanted to get a list of parts together so I can have everything ready when the time comes.

Does anyone have thoughts about the sprag?
 

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For the hiccup it sounds like normal misfiring. You can improve it by syncing the throttle bodies, adjusting the fuel trim, and using an aftermarket EPROM.

It all depends on how severe it is. Mine has done it forever at idle, and occasionally surges slightly at part throttle. Not enough to upset your ride or cause mid-corner issues. If yours is dropping a cylinder abruptly all the time it could be a fueling or electrical issue.
 

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Discussion Starter #6
vtwin, im glad to hear your concurrence with my thoughts. Did you end up replacing the whole unit? or just the spring that wraps around it? I've seen other's use the spring off a fork oil cover with positive results, but there are two entire (used) assemblies on ebay right now.... (what would you suggest)

JEC, its good to know that its not something more serious. Once the bike is hot, it will maybe do it 2-6 times per 10 minute in-town run?! Do you know a good rule-of-thumb on the fuel trim pot on the ECU ? i've never messed with it, but know the previous owner did. and do you have a suggestion on aftermarket EPROM?

THANKS AGAIN, ALL
 

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Sounds like the sprag clutch could be on it's way out - for what it's worth I wouldn't fit a used one as it's a big job to do only for it to (potentially) fail again shortly afterwards and I don't think they're too costly new.

As for the ECU trimmer, unless you have a means of testing the exhaust CO and know for sure that TPS & thottle balance is good then I wouldn't touch it. But the bike would benefit from full TPS reset/throttle balance/CO level setting.
 

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Discussion Starter #8 (Edited)
DukeDesmo, Thanks for the thoughts! I will look in to the new parts. Regarding a TPS,throttle, and CO tune, i have a manual (italian pdf... hehe) but would probably need to get an english manual to properly do it! Do you personally do that yourself? (the CO testing would be impossible without a shop tool, i would assume)



-- BATTERY --
Issue 3 and maybe part of issue 2??
I checked the voltage this morning and when I got home (hot)

start : 12.x volts off, 13 volts idle, 13.5 low rev (up to 5k rpm)
return : 12.8 volts off, 12.8 volts idle, 13.5 low rev (up to 5k rpm) - seemed to float around a lot

...maybe part of it is that my charging system is not healthy? (i replaced the plastic (melted) connectors on the regulator with directly joined, soldered, dielectric grease and then heat-shrinked wires.
 

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DukeDesmo, Thanks for the thoughts! I will look in to the new parts. Regarding a TPS,throttle, and CO tune, i have a manual (italian pdf... hehe) but would probably need to get an english manual to properly do it! Do you personally do that yourself? (the CO testing would be impossible without a shop tool, i would assume)
I do set TPS/balance/CO myself, it's not too difficult but you need a voltmeter, vaccum gauges and CO meter - you could buy all these for the cost of taking it to the dealer. ;)

There was a good writeup of how to set TPS etc posted on the site a while back, below is a copy of it;

A common error is to set the TPS with the rear butterfly closed, not the front one. The balance bar needs backing off to make sure. You must set the TPS on the front butterfly position.


Here's probably the best description of "how to" around. Taken from the FIM website.
The only addition I would make would be the backing off of the balance bar mentioned above. You MUST set the TPS to the front butterfly being closed, not the rear holding the front open.
• Set the Throttle Position Sensor on the throttle shaft. To correctly do this you must:

o Completely back off the idle stop screws on both throttle bodies.

o Use the Mathesis tester or a Digital MilliVoltMeter to read the
throttle sensor voltage. To do this you should tap the butterfly with your finger to ensure that the butterfly is completely closed against the body. Then you turn on the ignition and measure the voltage on the throttle sensor:
 P7 or P8 ECU: Pins 11 and 17.
 1.6M ECU: Pins 16 and 30.
 1.5M ECU: Pins 22 and 11.
o If the sensor does not read 150mV Plus or Minus 2mV then you need to adjust it:
 Slacken the lock screws on the throttle sensor using a screwdriver or 7mm socket.
 Carefully move the sensor whilst reading the voltage.
 Retighten the lock screws a little at a time, each time reading the voltage and adjusting the sensor.
 Note that you should probably overshoot the reading by about 5mV on slack screws, because when you tighten them the reading will change by about 5mV.
 Repeat until perfect. This takes a lot of practice.
o The factory manuals specify +/- 5mV but we feel that this is not accurate enough. many owners will attest to the difference in performance when the sensor is set perfectly.

o Re-set the throttle stop screw (or screws) so that the engine idles at around 1200 rpm. This is not a final setting for the stop screws, merely a step in the procedure. Typically this will produce a voltage of around 300mV on the TPS. This value is completely arbitrary and is not important. Many people misunderstand the factory manual in this regard and will try resetting the TPS until they get 1200 rpm idle and exactly 300mV on the sensor. THIS IS WRONG !!!. The actual voltage on the sensor at idle is irrelevant to correct sensor positioning on the throttle shaft. Trust Me !!
• Synchronise the Butterflies:
o Close the airbleed screws completely by adjusting CLOCKWISE. If you don't do this then the throttle vacuum will still reflect any air passing through the bleed channels and the butterflies will not be perfectly synched.
o Attach vacuum gauges to the manifold port on each cylinder and run the engine.
o Adjust the throttle butterfly link shaft until vacuum is identical.
o Rev the engine and confirm that vacuum tracks on both cylinders throughout the throttle and RPM range.
o Re-adjust the link shaft until satisfactory results are obtained.
o Do Not adjust the throttle link shaft after this point.!!

• Set the IDLE Balance by adjusting the airbleed screws counterclockwise and confirming that the vacuum is identical for both cylinders at idle. You can rev the engine and observe vacuum tracking through the rev range, and then observe idle vacuum restabilising. NOTE Since the airbleeds are designed to iron out any irregularities in the throttle's function, by their nature there is no default setting, unlike the idle screws on a carburettor. If anything the default setting is fully closed. Airbleeds can also be balanced using a 2 channel CO meter. In this case, just adjust the bleeds until both cylinders have the same CO.
• Adjust the IDLE Mixture. Finally you get to set the CO Trimmer ! This will affect both cylinders by the same amount, so you need to set the airbleeds first. A typical CO figure for idle is 4% to 6%, but automotive regulations usually specify a CO of under 1% to meet emmissions standards. A V-twin will idle very poorly if the CO is set below 1%, so if you are really bothered try a setting of about 3%. Note that you may need to finesse the airbleeds at this stage.
• Adjust the IDLE RPM. Set the idle rpm at the manufacturer's figure (usually 1100 - 1200 rpm) by adjusting the throttle butterfly stop screw (or screws). We recommend 1200 rpm for Ducatis and Guzzis, possibly 1500 rpm for Ducati 996SPS models.
• Finally, note that the last three steps are usually repeated until an acceptable balance of Idle Balance, Idle Mixture, and Idle RPM are obtained. This is normal. Do Not adjust the throttle synchronisation link shaft once it is set in the early stages. If you do this now, you will need to go through the entire sequence again.
So hopefully you will have an engine which now idles, accelerates, and delivers full power faultlessly. Again, if you are not confident about all of these steps, then we suggest you use a dealer who has the skills and equipment. It is not worth adjusting the CO trimmer unless the entire sequence is followed without skipping any steps.
 

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have to be careful with dialectric grease

Shazam quote:
Using dielectric grease on connector pins can be a source of unwanted high resistance. Ferrari used to put dielectric grease inside all of their engine connectors (that will see water) but they eventually found out that it caused problems. They issued a service bulletin that advised cleaning out all of the grease and to use instead a contact enhancing product called Stabilant 22.

Application Note 20 - Automotive service

from here:

No, Vaseline or WD-40 has no place in electrical connectors or components.

Motorcycle electrical systems are more exposed to the elements than cars so it’s important to keep the system sealed against water infusion to avoid corrosion of the electrical connections.

In particular, the electrical connection between the alternator and the regulator carries a very high current, so corrosion there will lead to overheating the connector and adjacent wiring. I recommend eliminating this connector entirely using solder and shrink-tube insulation.

Another problem area is the rubber boot on the electrical connection to the starter motor. It leaks, collects water and corrodes the connection. Here, you need to clean the connection and then seal it watertight with silicon sealant.

Every instrumentation, power and ground connection on the bike is a potential problem. So the best approach is to prevent water from reaching the connections whenever possible and to reduce electrical resistance at each connection.

Care should be taken to avoid forcing water into the connections so set your wash hose nozzle on spray (not stream) and avoid using the high pressure commercial wash/steam systems on your bike.

The connectors are designed to be waterproof, but over time seals will harden and eventually moisture will get in. Some owners make it a practice to using dielectric (non-conducting) grease to keep water out of connectors that don’t get hot enough to cause the grease to liquify.

For connectors that stay cool enough to let the dialectric grease to remain thick, use it to seal the male-female seam so as to prevent water from entering the connector. Don’t put it on the connecting pins themselves. Use in connectors that get hot runs the risk of the grease liquifying and getting on the pin surfaces.

Using dielectric grease on connector pins can be a source of unwanted high resistance. Ferrari used to put dielectric grease inside all of their engine connectors (that will see water) but they eventually found out that it caused problems. They issued a service bulletin that advised cleaning out all of the grease and to use instead a contact enhancing product called Stabilant 22.

Application Note 20 - Automotive service

When applied to an electrical connection Stabilant 22 becomes conductive. The manufacturer claims that it is as good as a soldered joint.

VW, Porsche, BMW and Ferrari all recommend the use of Stabilant 22 on electrical connectors. You can buy it at your local VW parts department. Don't be shocked at the price, a 5ml tube is around $40.

A 15 ml bottle of Stabilant 22 costs $61 a NAPA stores. It's packaged under NAPA's Echlin brand, so when specifying the part number the "line" is ECH and the part number is CE1.

There are some other specialty products that try to address the connector protectant issue. Deoxit for example:

Shopping Cart - CAIG Laboratories, Inc.

Another is Boeshield T-9

Use an electrical contact cleaner instead to remove any grease and oil that is causing conductivity problems. Sticky relays should just be replaced because in the long run they’ll probably fail when you least want them to.

On a wet bike that won’t start, I recommend first using a leaf blower to dry everything out and let it sit in the sun for awhile. It'll start eventually. Then waterproof it.
http://www.ducati.ms/forums/80-hall-wisdom/64479-protecting-electrical-connections.html

Silicone grease - Wikipedia, the free encyclopedia
 

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It's hard to verify exactly without a gas meter, but you can adjust by ear. You set it in the middle, then turn one way until it runs bad, then the opposite, and find the sweet spot in the middle. Takes practice to do it that way though. Much easier to just check a gas meter and set it to 5% ish.

I had a 062 Senna EPROM for a while. It was my personal choice, I preferred it to the popular Ultimap EPROM. 062 is for 1.6m only, not the P8. I just got a Hypertrick EPROM from TomTom, it has a similar feel to the Senna but with a smoother delivery. TomTom is my recommendation for a good base EPROM.

Mine drops revs at idle here and there, not constantly. It used to stall until I set everything (I also raised the idle a few hundred rpm, lapped the valves and tightened the closing clearances). Now it just goes duh-duh-duh-da-duuuh-duh-duh-duh, like it misses a beat once and a while.


JEC, its good to know that its not something more serious. Once the bike is hot, it will maybe do it 2-6 times per 10 minute in-town run?! Do you know a good rule-of-thumb on the fuel trim pot on the ECU ? i've never messed with it, but know the previous owner did. and do you have a suggestion on aftermarket EPROM?

THANKS AGAIN, ALL
 

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Discussion Starter #12 (Edited)
Thanks for the info!!

The dielectric-grease stuff is not good to hear though, I was told to put it on electrical connections. I guess just on batteries that have a very compressed fitting (bolted on). I feel like an idiot for putting it on every ducati connection I could find..... wonder how I will fix that? maybe that explains it unwillingness to fire lately. Yesterday I cranked it (quick button pushes b/c of sprag) for a few minutes with nothing. Then, I had the loudest backfire I've ever had, ever! sounded like a gun shot crack, and echo'd throughout the area for what few like seconds... hehe whoops.

and JEC, i will definitely start looking in to some of the mentioned EPROMS. I need to do belts AND the valve adjustment, but valves scare me a little. I talked with a Brit a year ago and he gave me some good info but im still nervous.... maybe poor clearance is contributing to its starting issue? and hickups? Am I required to get a $300-400 kit of modified shims? or any specialty tools (other than a feeler gauge)?


Can anyone comment on the generator information I posted on 8/24/12? i feel like that may be another issue. Thanks!

THANKS again!
 

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Discussion Starter #13
OK im really at my wits end - i need this bike running by tomorrow morning as its my only means of transportation right now.

I have the parts to fix it, and i CAN NOT GET THE DAMN STATOR NUT OFF!

I've tried my 18v dewalt impact and nothing. i have used a 4 FOOT breaker bar with a wrench and all I did was break my clutch-basket holder tool which was keeping the motor from moving. I tried the old gear-penny trick out of frustration, and it walked the penny through the gears and left me with a corrugated penny.
I specially bought a pneumatic impact driver (625ft/lb reverse) and it doesn't to a damn thing!

WHAT IS GOING ON????????????????????????




I am ready to cut the @*(&# stator bolt off - this job needs to get done.


any advise?
 

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The nut might have loctite on its threads , Heat will soften the
loctite and the nut should come off.

brian.
 

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Discussion Starter #15
Well.... *sheepishly smiles* turns out my air compressor's pressure gauge was shot....... I thought I was at 90psi but actually was at 40-ish... I used a metal-band oil filter wrench and put it around the stator, then (with a GOOD air compressor set at 80psi) I hit it with the IR Thundergun impact and the nut few off!!
Thanks for the help.
 
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