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  1. #1

    97' SLX785 Pro No tach & power valve

    Been fighting this thing for a while now. Would not accel past 20MPH, thought I had fuel probs, finally unhooked grey wire & clipped ends of plug wires & it runs great, topped out @ 57.6 on speedo. Tach still does not work & I remember reading something about how Power valves will not work without tach. Where should I look to fix the tach? Totally new issue today after about 10 minutes of riding it made some nasty clunking noise so I shut it off. Have not had a chance to check into this yet.

    Thanks, Ryan


  2. #2
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by yeehaa View Post
    ...Tach still does not work & I remember reading something about how Power valves will not work without tach. Where should I look to fix the tach? ...
    Does the MFD work otherwise, or is it completely blank?

  3. #3
    everything else on MFD works.

  4. #4
    Good news on clunking, not engine, just pump issues.

  5. #5
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    Quote Originally Posted by yeehaa View Post
    everything else on MFD works.
    Looking at the wiring diagram, the MFD tachometer has no connection to the CDI. So the problems may not be related.

    For the MFD with no RPM display, check that you have proper charging voltage at the battery when the engine is running. Should have about 14.5 volts with engine running, and it should be stable as RPM changes.

    If not getting 14.5 volts, check the wiring for the LR regulator module, and make sure it is properly grounded. Also check the Red/Purple wire to the stator, and the stator coil resistance (Red/Purple to Yellow, with the wires disconnected from the terminal board).

    Next check the Yellow wire. This is the RPM signal from the stator to the MFD. It only goes to the LR module, and the MFD.

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    Quote Originally Posted by yeehaa View Post
    everything else on MFD works.
    The voltage regulator is probrably bad i just had one like that awhile back

  7. #7
    Is LR the regulator? Where is it located?

    Thanks.

  8. #8
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by yeehaa View Post
    Is LR the regulator?
    Where is it located?...
    That sort of info is in the service manual, and the Polaris parts cross reference web site

    Inside the electrical box, have a look there.

  9. #9

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    Quote Originally Posted by yeehaa View Post
    Is LR the regulator? Where is it located?

    Thanks.
    Yes it is it's in the electrical box

  10. #10
    Great, thanks guys. I will post if that fixes it.

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