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Thread: Cotten, I moved shovelhead operating temp here

  1. #11
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    Nov 2016
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    Davenport
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    Try putting new weights and springs in and then using a timing light to time it at 2000 rpm. Those weights wear out often.

  2. #12
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    Mar 2017
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    Quote Originally Posted by 1937hd View Post
    Try putting new weights and springs in and then using a timing light to time it at 2000 rpm. Those weights wear out often.
    Been trying to find nos items with no luck. I did check the pins and weights for wear and there was no wear on either, cleaned and lubed with light weight synthetic grease. The springs return great with very little tension. That's all I can do for now to the timer.
    I will stobe time it tomorrow at roughly 2000 rpm. Oh, I can hook up a tach, I have one for my bike, but opted for the cigarette lighter instead.

  3. #13
    Join Date
    Aug 2004
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    Beautiful Northern New Mexico
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    Thinking out loud here, perhaps the Servi-Car weights and springs are set up for a slower advance due to the needs of the bike, and those needs somewhat mimic a sidecar tug...
    And simple compression plates under the cylinders could help with the ping.

    On a manual advance timer the rider can control the advance curve which I find quite handy in traffic or steep grades on my sidecar rig.
    Robbie Knight Amca #2736

  4. #14
    Join Date
    Mar 2017
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    Hopefully I can get it with the strobe light, if not the servicar weights and springs.
    How would I use a manual timer without the mounting at the block for the timer cable? Is there an adapter plate or would I have to fashion one? Boy !this is turning into some work.
    I do not have this much trouble with my hopped up 289 hipo with the same total timing of 35 and 2.5 points up higher on compression.

  5. #15
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    Mar 2017
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    Quote Originally Posted by T. Cotten View Post
    The first thing I would do, Ryan,..

    Is to strobe it to where the line is in the front of the hole, and see if anything improves.

    If its clacking away from stop signs before the tank is hot, no cooler is going to help.

    Do you know what pistons are in it? Can you give us a compression reading?

    ....Cotten
    Ok, Compression testing: cyl one is 65 initial push and 143 psi Cylinder two initial push is 65 and 145 psi. This was tested on a warmed up engine.

    So my compression ratio is almost 10:1 (145/14.7=9.8)

    I just strobe timed is and going on a test ride.

  6. #16
    Join Date
    Jun 2001
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    Central Illinois, USA
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    That explains a lot, Ryan!

    So much for 'octane boosters', huh.

    ....Cotten
    PS: Somewhere I have a pair of 1/16" cylinder base shims I ran in the late '70s-early '80s.
    Suddenly they are worth something to somebody.
    Last edited by T. Cotten; 09-12-2020 at 05:22 PM.
    AMCA #776
    Dumpster Diver's Motto: Seek,... and Ye Shall Find!

  7. #17
    Join Date
    Mar 2017
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    Oh my gosh, I make a stupid, stupid mistake. I left the ignition switch on, by mistake, for about 45 minutes after doing the compression test and cracked my coil in a few places. The circuit was protected by a 30 amp breaker and then went through a 15 amp breaker. I am so lucky I was beside my bike when this took place.

    As far as the timing went as far as comparing strobe light timing to static timing: Static timing was advanced so much that the line was just outside the window. I retarded the timing so the line was in the center of the window at or just over 2k rpm.

  8. #18
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    Jun 2001
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    Leaving the switch on cracks coils, Ryan!?!

    This is new to me, as is everything electrical.

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

  9. #19
    Join Date
    Mar 2017
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    Quote Originally Posted by T. Cotten View Post
    Leaving the switch on cracks coils, Ryan!?!

    This is new to me, as is everything electrical.

    .... Cotten
    This was new to me as well Cotten, I was putting things back together after timing, compression testing and adjusting the front brake all while the switch was on. I was picking up tools and smelled something hot and then I started hearing something crackle, my eyes went straight to the coil and then it started cracking and splitting apart before my eyes, I looked at my switch and instantly turned it off, my coil was very hot and my ignition switch was pretty warm as well.
    Why did this happen, why did it take so long to happen and why didn't the breakers protect it? Oh, the points were closed.

  10. #20
    Join Date
    Jun 2001
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    I knew that if the points were closed, Ryan,...

    That it would drain the battery; If it cooked the coil, I'd guess that was one helluva battery.

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

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