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V7/850GT tachometer on 1000 California engine?

Discussion in 'Loop & Tonti' started by ChopSauce, Nov 7, 2018.

  1. ChopSauce

    ChopSauce Tuned and Synch'ed

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    I am afraid I lost my links to loopframe Guzzi techs...

    So, I suspect that the tacho won't give accurate readings (but 0.5 or 2x, maybe) even though I am not sure at all.

    Does anyone here know - at least where to find the information - please?
     
  2. Amboman

    Amboman Cruisin' Guzzisti

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    You're wanting to use the electronic Loop tach with the dual-point timer of the later engine? I don't know of anyone that's done that successfully.
     
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  3. ChopSauce

    ChopSauce Tuned and Synch'ed

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    Yes, that's it! Do you know how the tacho / ignition works?
     
    Last edited: Nov 7, 2018
  4. john zibell

    john zibell Moderator Staff Member GT Famiglia

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    Looking at the schematic in the downloads section the tachometer gets it signal from the ignition coil. Since there is only one coil on the loop frame and two on the California 1000 I don't think you will get accurate readings. If you have a friendly electrical engineer he might come up with a circuit to obtain signal from both coils (that wouldn't impact coil operation) which would be needed for anything close to accurate.
     
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  5. ChopSauce

    ChopSauce Tuned and Synch'ed

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    Thanks a lot!

    I wasn't sure but this was - roughly - was what I had in mind. The loopframe tacho counts the inputs from a single coil firing twice - that is would read twice the RPMs when connected to a "Tonti-esque ignition system" ...

    ... my tacho will be resto-modded by a specialist, which should be able to modify its internals but I think I'll stick to the mechanical solution and keep things as much close to the original as possible.

    That wasn't much of a good idea, sorry.
     
  6. john zibell

    john zibell Moderator Staff Member GT Famiglia

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    I'm thinking it would read half the actual RPM if connected to only one coil. Some diodes in a circuit should provide the two pulses to the tachometer without making the coils confused on when to fire. Still the mechanical solution would be easier.
     
  7. ChopSauce

    ChopSauce Tuned and Synch'ed

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    Oh yes, this I was missing. Thanks - again!
     
  8. kiwi dave

    kiwi dave GT Reference

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    I remember that there were two different tachometers for the California 1100, I think the carburetor version was different from the injected 1100i, so that swapping would make the tachometer to read half or twice, depending on the direction of the swap.

    If you could locate the correct one (try before buy?) then one might be suitable.
     
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  9. ChopSauce

    ChopSauce Tuned and Synch'ed

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    Thanks Dave!
    I wish I could find an 1100 injected engine, but that's noted ;)
     
  10. GT-Rx®

    GT-Rx® Administrator Staff Member

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    Where are you located? I have several used motors available.
     
  11. ChopSauce

    ChopSauce Tuned and Synch'ed

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    Sorry. I forgot to mention my location before.
    Way too far, I'm afraid!

    I doubt you would carry a used Guzzi engine in your luggages if you were to come and visit Paris :cool:
     
  12. ChopSauce

    ChopSauce Tuned and Synch'ed

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    I'll investigate that. I found an instrument builder to make a worthy copy of the V7Sport tacho out a mechanical - more recent - one, but this was too expensive: over 500$.

    The price might fail if I were to order at least 10 repro graduated disc (dunno the english for "fond de compteur") but I doubt there are that much people interested in the Guzzi community ...

    The B plan is using a V7 tachometer as an erzatz for the (missing) V7Sport one, hence this post.

    So I'll scope the signal from the distributor at some latter point - & see what I can do - thanks!
     

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