Moto Guzzi V85 TT

Discussion in 'Moto Bellissima: All Other Dualsports' started by cabanza, Nov 7, 2017.

  1. hawkster

    hawkster Been here awhile

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    Fantastic! I hope this is the problem with mine and that fix is easy. Glad you got your bike back in time for winter. I'm snowbirding soon and will carry my small bike with me while the guzzi hibernates. If this is the common problem I'll get it fixed this spring.
  2. rac3850

    rac3850 ............

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    This is exciting news - if the CPS issue is a "simple" air gap adjustment issue. However, the "lock nut" explanation has me a bit confused. According the E5 parts diagram I have, the CPS sensor body is bolted to the flywheel cover with two m5 x 12 torx screws (#5). If I'm reading the diagram correctly, the sensor body is fixed to the flywheel cover and reads some kind of indicator (optical?? magnetic??) on the outer surface of the flywheel. I'm guessing the "plate (#6)" just provides a standoff for the power cable so it doesn't rub against the rotating flywheel. I don't see a lock nut arrangement or an indication that the sensor body has play in the mounting to allow adjustment. It seems it would be difficult to measure and adjust the air gap since it is only "created" when the flywheel cover & stator assembly is placed over the flywheel. If it is adjustable, seems it would probably be a trial and error process to adjust, assemble then read the sensor output to see if it was "in spec." I'm probably missing something, misinterpreting how the CPS mounts, or the parts diagram is not representative of the actual parts and assembly (i.e., my parts diagram is out of date).

    upload_2021-10-23_7-43-44.png
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  3. Bloviator

    Bloviator Been here awhile

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    Well, after a somewhat rocky start due to the swingarm issue I have to say that I am enjoying the hell out of the bike, now that it has been repaired. I love the engine, smooth clutch and the suspension. I find the bike to be a real joy to ride! It's a hoot! :clap
  4. DesertPilot

    DesertPilot Long timer

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    The second service interval is done, the new OEM tubeless wheels are installed (complete with a spiffy set of Kurveygirl 83 degree angled valve stems), and life is good! :clap

    Of course, the forecast for tomorrow is for pissing-down rain, so I may not get to celebrate all this with a ride, but hey, life is still good!
  5. DesertPilot

    DesertPilot Long timer

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    They had the bike on their dino? Awesome! How did they manage? I can never get the darn thing to stay balanced :D

    GuzziOnDino03.jpg
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  6. guzzijason

    guzzijason Been here awhile

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    Re: the E5 stumble/surge
    Perhaps there is some adjustability of the crank position sensor that is not apparent in the diagram. Wish I could have laid eyes on the part myself. In my case (as previously noted) the fix was to completely replace the stator/sensor assembly.

    This air-gap issue is interesting, though - and it makes me wonder if *all* of the E5 stumble/surge problems are actually the same root cause, just with varying degrees of the problem. For instance, if the gap was only "slightly" off, then perhaps the signal was still good enough that simply moving the wiring around (as was called for in the original service bulletin) was sufficient to resolve the problem. However, for others like mine and Joe's, the problem was more severe, requiring more drastic fixes. Maybe mine could have been fixed by adjustment as well, and they just didn't realize that yet at the time?

    Can only speculate. I do wish I could actually see the parts for myself to better understand. I also wonder if any updated service bulletins have been issued for the problem yet.

    __Jason
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  7. moparnut

    moparnut Been here awhile

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    Looks to me that there are two sensors but maybe not. Could either of the brackets, if there are two, have been bent or mis-stamped causing an incorrect gap? Seems like a legitimate cause of the problem.
    kk
  8. ScottTheFalcon

    ScottTheFalcon Been here awhile

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    I've used a lot of a device called a Hall Effect sensor over the years for measuring the passing of teeth or cogs. They look like a small bolt but instead of a head there are a couple of wires coming out. You screw these into a threaded hole and apply a lock nut to hold it in the right location - simple. And they are a current based device rather than voltage, so insensitive to electrical noise like the adjacent alternator and it's wiring. When I read the description earlier I thought yup, I get that.

    The diagram shown with 2 bolts (5), a bracket (6) and an un-numbered sensor looks way different. The only adjustment I could see from that would be using the tolerance in the holes of the sensor, which would be little, and bad engineering. And to be honest the engineers who've designed this motor have done a great job, all things considered. It feels like we are close to the issue but I can't really visualise it yet.
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  9. rac3850

    rac3850 ............

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    I agree it could be a cause of the problem. It looks to me like the sensor is bolted directly to the cover, there isn't a sensor bracket. What looks like a bracket is (IMO) a "plate" to secure the cable from vibrating down onto the rotating flywheel, i.e., the plate is not part of the sensing mechanism.

    If I read it right, there is only the one sensor in the E5. The other larger diameter cable attached to the stator windings would be for the voltage output to run the bike and charge the battery. Also, for comparison, below is the E4 stator parts fiche. As can be seen, there is no sensor, just the power cables attached to the stator windings, with a plate to protect the cable.

    Also below is a picture of the "non'sensor" alternator cover from the E4 engine manual. It seems that the E5 alternator cover would be somewhat changed as there are two screws that hold the plate and the sensor in place vs. the one screw holding the plate alone in the E4 version. Sorry, I don't have an E5 engine service manual with comparable pictures. Wish I did.

    I find it interesting, that for the V85TT parts fiche, this assembly is called the "CDi Magneto / Ignition" assembly, but in the V85 E4 engine service manual, the comparable section is called "Generatore," the R&R process calls it "Alternator cover removal," and the parts diagram calls the parts the "magnet flywheel" and "stator." I believe there are fundamental technical differences between alternators, generators and magnetos.

    upload_2021-10-24_19-47-42.png
    upload_2021-10-24_19-48-2.png
  10. ScottTheFalcon

    ScottTheFalcon Been here awhile

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    I think there's a lot of historically used terms that became somewhat inaccurate in translation. Generators are more alike than different to alternators but no modern machine uses a generator, for efficiency reasons if nothing else. Anyway they are basically to keep the battery charged.

    The CDi Magneto / Ignition is a whole different thing related to the engine ignition, for which the engine crank position is super handy information. Didn't CDi ignition belong to the '80s or so? There is no CDI or magneto in these machines, at all.

    We have to read these translated documents with a far bit of fuzz allowed.

    Also, we've discussed that there are 2 off part (5) in the E5 bikes and only one in the E4 bikes. That (those) screw(s) screw into the casting, so it looks like that casting has changed?
  11. rac3850

    rac3850 ............

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    Could it be that the sensor body holds the threaded Hall Effect sensor device, and there is a locknut integral in the sensor body itself to hold the sensor to the proper depth in the sensor body? We just can't see it in the diagram. I also didn't see that the sensor body and its two bolts would allow for any play in its mounting, I agree that would be very poor design.
  12. ScottTheFalcon

    ScottTheFalcon Been here awhile

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    Yeah maybe, then it could be adjusted after some assembly, before the final assembly. Okay :)
  13. RedHawk47

    RedHawk47 Adventurer Supporter

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    Here is the service manual photo for the E5 stator harness
    upload_2021-10-24_21-6-4.png

    Dan
  14. moparnut

    moparnut Been here awhile

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    "I think there's a lot of historically used terms that became somewhat inaccurate in translation. Generators are more alike than different to alternators but no modern machine uses a generator, for efficiency reasons if nothing else. Anyway they are basically to keep the battery charged."

    I think that some auto manufacturers are using a generator/starter unit in their vehicles that shut down at stop lights etc. It is my understanding that Chrysler uses this type of system to take the wear and tear off a traditional starter. I know that some 60's Yamahas used this system and called it a dynamo.
    Kk
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  15. ScottTheFalcon

    ScottTheFalcon Been here awhile

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    Drifting away from the V855TT for a moment but yeah interesting. I had a dynamo on my pushbike back in the late 60's which was cool. And dynamos / generators _can_ be DC where alternators are by definition AC and need the rectifier. Both need the regulator.

    And cars that stop and start themselves - I just got back home in a car that does that. Push the button to start - I think it makes the same sound to start as when I take my foot off the brake at the traffic lights. I just assumed it was a conventional starter but ECU controlled. I'm never getting under the bonnet of a car to find out...
  16. DesertPilot

    DesertPilot Long timer

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    Am I the only one here who remembers replacing worn out carbon brushes on old automotive generators? On cars with 6V electrical systems?
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  17. jgad60

    jgad60 Adventurer

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    The explanation is a bit confusing to me as well because everything I have ever worked on with a crank position sensor, which admittedly isn't a lot, has had no adjustment. I specifically asked about the stator issue that GuzziJason had and they said it was not the same issue and implied that they had investigated that possibility. Is the diagram you shared a 2021. I presume it is as I understand the CPS on the '19 & '20 models is somewhere else. Anyway, the bike is running well and since they had to remove the front of the engine to do the repair I did not actually see it. I'm trying not to over think it since they are the dealership and it is under warrantee but like many of us, I do want to understand what is going on inside my bike. I really miss our old dealership, Moto International. They would have invited me in to see and understand what they were doing.
  18. ScottTheFalcon

    ScottTheFalcon Been here awhile

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    Yes :)
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  19. JohnD01

    JohnD01 Been here awhile

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    We used Starter/Generators in the Huey's back in the 60/70's, probably stilll in aircraft today.
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  20. worwig

    worwig Long timer

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    The crank sensor on the Guzzi big block motors, for many years, had to be shimmed or you would have issue. I even encountered one where the owner did not know there were shims and the sensor rubbed against the timing wear, destroying the sensor. The data I have recommends a gap of 0.7 to 0.9mm.
    But yes, what I am seeing in this design doesn't look like there is a way to adjust or shim that sensor. Surprises me a bit.