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  • #46
    Originally posted by T. Cotten View Post


    PS: I put my '65 circuit breaker upon a SUN machine to diagnose bouncing points once; The advance was nearly instantaneous, with almost no "curve".
    Ditto on 67-70 xlh automatic timers. I rebuilt a unit with NOS springs and it was at full advance by ~2000rpm.

    Most bikes I have worked on with mechanical auto advance from the 60s to late 70s, regardless of make, are already into the curve at or just over idle speed. The move to electronic in the late 70s for most makes brought more managed curves.

    I find most aftermarket timing parts these days to be of very poor quality and short life span. I hunt NOS like a bird dog at meets and the flea bay.

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    • #47
      The 67-early 69 timers were fully advanced at 900 rpm, the late 69 at 1600 rpm.
      vph-d

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      • #48
        Originally posted by vph-d View Post
        The 67-early 69 timers were fully advanced at 900 rpm, the late 69 at 1600 rpm.
        vph-d
        As Kitabel once pointed out, Folks,..

        They are actually an 'auto-retard'!

        ....Cotten
        AMCA #776
        Dumpster Diver's Motto: Seek,... and Ye Shall Find!

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        • #49
          Yep, why the spring diameter/rate is so critical as I mentioned earlier. If the spring rate is incorrect, let say to stiff in this scenario, the centrifugal advance will increase in RPM before reaching 35 degrees. This can leed to retarded timing at lower RPM's of cruise speeds which causes excessive engine heat and adverse thermal affects on the motor oil. As cylinder port dynamics, mainly intake as well as gasoline chemistry changed over the years you'll note the variation in spring rate which affects the all in full advance advertised in the service manuals of different years groups and engines. Back to a lot of the aftermarket centrifugal springs being to stiff causing Freeman's heat issues most likely...

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          • #50
            I've found Tedd's to SOFT. I did track done OEM through H-D's computer listing of dealers old stock.
            DrSprocket

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            • #51
              Originally posted by dukekleman View Post
              Yep, why the spring diameter/rate is so critical as I mentioned earlier. If the spring rate is incorrect, let say to stiff in this scenario, the centrifugal advance will increase in RPM before reaching 35 degrees. This can leed to retarded timing at lower RPM's of cruise speeds which causes excessive engine heat and adverse thermal affects on the motor oil. As cylinder port dynamics, mainly intake as well as gasoline chemistry changed over the years you'll note the variation in spring rate which affects the all in full advance advertised in the service manuals of different years groups and engines. Back to a lot of the aftermarket centrifugal springs being to stiff causing Freeman's heat issues most likely...
              Yes, I found the overheating problem after restoring the spring, if I didn't change the other settings, I tried to adjust it clockwise, now it's better, but I'm not sure if it's accurate. I ordered the timing light and want to use it to adjust it accurately, but I didn't find the corresponding video on Youtube. I need the video to help me use the timing light correctly.

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              • #52
                Timing lamp
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                • #53
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                  • #54
                    You'll need to get the engine up to operating temperature. Install the red colored induction clamp onto the front cylinder high tension leed (spark plug wire) remove the timing inspection plug on the left crankcase half. I recommend using a auxiliary tachometer to verify RPM. A second person is very helpful as well. Bring your RPM to 2,500. Your timing mark should be centered in the inspection hole. If not, adjust the timer accordingly. Now go down in RPM and slowly start raising the RPM. Note the RPM and point when the timing mark centers itself in the inspection whole. The hope is that your achieving your 35 degree advance slope earlier on in RPM. Full advance by 1500 - 1800 RPM. Your advance weight springs, which ever rate they are, along with friction on the pivot points will dictate the RPM point of full advance.
                    This is the best explanation I can type on a forum from a cell phone screen. Laughing...

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                    • #55
                      Originally posted by dukekleman View Post
                      You'll need to get the engine up to operating temperature. Install the red colored induction clamp onto the front cylinder high tension leed (spark plug wire) remove the timing inspection plug on the left crankcase half. I recommend using a auxiliary tachometer to verify RPM. A second person is very helpful as well. Bring your RPM to 2,500. Your timing mark should be centered in the inspection hole. If not, adjust the timer accordingly. Now go down in RPM and slowly start raising the RPM. Note the RPM and point when the timing mark centers itself in the inspection whole. The hope is that your achieving your 35 degree advance slope earlier on in RPM. Full advance by 1500 - 1800 RPM. Your advance weight springs, which ever rate they are, along with friction on the pivot points will dictate the RPM point of full advance.
                      This is the best explanation I can type on a forum from a cell phone screen. Laughing...
                      Ok, thank you. I will operate in this way after receiving the required tools.

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                      • #56
                        Originally posted by dukekleman View Post
                        You'll need to get the engine up to operating temperature....
                        I always let them cool down, Duke!

                        Or timed them as soon as they would start and run; It was a lot easier on the fingers.

                        And produced identical results.

                        .....Cotten
                        Last edited by T. Cotten; 11-14-2022, 07:51 AM.
                        AMCA #776
                        Dumpster Diver's Motto: Seek,... and Ye Shall Find!

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                        • #57
                          I've run into heat related issues with timing variations. Due to growth and expansion along with all the gears and directional power flow changes of those engines. Ignition coils also react different (Ohm's variations on primary/secondary side) with heat. Full operating temperature is my preferred method although I agree that hot oil and engine components are no fun to deal with.

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                          • #58
                            I know nothing of exotic coils, Duke!

                            Its hard to believe component expansion significantly changes where you see the line with a strobe.

                            (But I swear by stranger things...)

                            ....Cotten
                            PS: If a significant difference were observed, I would inspect the 'intermediate' drive gear sideplay. They can be diabolical.
                            Last edited by T. Cotten; 11-14-2022, 02:00 PM.
                            AMCA #776
                            Dumpster Diver's Motto: Seek,... and Ye Shall Find!

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                            • #59
                              Merry Christmas, everyone. Today's temperature is 37.4'F, I go out to ride for an hour, front 300'F, after 250'F, is this temperature normal?
                              Last edited by Freeman; 12-26-2022, 03:28 AM.

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                              • #60
                                Well, that's a loaded question when answering if that's "normal" . Yes and no. I'd like to ask first where on the engine cylinder areas are you "exactly" measuring these temperatures. Me knowing that is important in my answer.
                                Merry Christmas as well!

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