doesn't like to run 30 mph

Discussion in 'Classic Models' started by vasti5429, Sep 20, 2009.

  1. vasti5429

    vasti5429 Member

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    ok this is pretty much driving me nutts .
    77 shovel . starts rite up idles fairly good . while going about 30 she will buckle and buckle . though maybe carb rebuild carb (s&S) reset the points and gap even tried swapping carb to another one does the same thing . havent delt with points in a long time , someone said something about a plate behindn the points that locks up and it will cause it havent taken apart yet . also points are timed far advanced as they can go runs better there . shes fine if you give it gas and want to go 100 mph . whats causing this .
     
  2. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

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    It does sound to me like your advance mechanism is not working correctly. These are the old inertial weights that advance the ignition as the engine speed increases. If you have to manually advance the plate to get the bike to run right, that is a dead give away. See the extract from the Shovel manual attached. I have included the maintenance section AND the disassembly/reassembly section from the book. If you do not have that manual, it is in download and you can get that once you have reach 150 posts or more.

    I suggest you disassembly the ignition system and ensure that everything is working correctly. I would replace the plugs, points and condenser if you haven't done so recently. Follow the '77 procedures from the book. See if that helps, and let us know.

    TQ
     

    Attached Files:

  3. NEWHD74FAN

    NEWHD74FAN Experienced Member Retired Moderators

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    As TQ says, there may be counterweights & springs under the points/condenser breaker plate. You may have to remove the plate to see if there is a timing advance pivot assembly underneath, as the PDF does not show or indicate anything is underneath other than saying it has "--automatic advance". Only use dry lubricant like graphite in the pivot areas, as dirt and moisture may find their way in there and oil or grease will just gum up the advance weight area with a slurry mess.
     
  4. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

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    As NEWHD74FAN is pointing out, there are four different ignition systems used on the Shovels from '66 to '84. The first was the distributor-like circuit breaker, then three systems in the nose cone. The first from '70-early '78 had a mechanical advance system. Starting in late '78 HD used breakerless ignition, with two different ones. So in '77, your engine should have the mechanical advance system in the nose cone.

    TQ
     
  5. vasti5429

    vasti5429 Member

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    thank you . did take the back plate of points off to get to the advance mechanism , actully didnt look too bad but bit rusty. cleaned and lubed , and put everything back together , and she actully runs pretty good , im happy now , can move on to the next project now . again thanks
     
  6. NEWHD74FAN

    NEWHD74FAN Experienced Member Retired Moderators

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    Good deal Vasti5429, now may I ask...do you have some pictures of your ride...I like old school bikes...:D