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  1. #1
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    Default Cosmic Shovel - '75 chopper rehab project

    On to a new donor and new opportunity to keep on tinkerin' and learnin'.

    Picked this up the day after I let go of the "Mutt Shovelhead" bike (separate thread).
    1975 with a ratchet 4-speed, aftermarket frame, etc.
    Hauled it back 2 hrs north from Charlotte in Tropical Storm Ian (fka hurricane Ian) when it rolled thru the Carolinas.
    Unfortunately, with the storm and rain, that meant no test ride. More on that below...

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    I nicknamed this thread the "Cosmic Shovel" because of the gas tank that I'm going to put on it later on. I really dig this bike as is. It's not my style. But I can live with it. So I'm in no hurry to tear it apart like I was the past few bikes. This I'm gonna ride for a bit and stockpile parts.

    After a good shakedown ride, and in classic Shovelhead fashion...
    - Timing hole plug bolt came loose. Almost lost it but didn't. Sprayed oil everywhere though. Fun.
    - Lost an exhaust mount bar bolt. That's ok. Still got one more.
    - Rear axle nut came loose. Wacked out alignment. Was a handful to get home.
    - Lost (or never had) the front oil tank mount bolt.
    - Cracked (or was cracked) one of the oil tank tabs on frame (that's ok... 1 out three mounts aint bad right?)
    - Rear brake is 50% gone. Front brake is 90% gone. All good. I ride slow.
    - Worst of all... pretty heavy valve knock on low RPM load (like pulling out and going up hills). Not good.

    The good news is that it has a lot of decent parts on it that will either stay (frame, fork trees, ratchet trans, compu fire digital ignition, etc) and a lot that I will replace/sell (the 3" belt drive, tins, seat, bars, wheels). Should be able to do a good little makeover eventually.

    Plan is to go 21/19 wheel combo. Little taller in the front (but not crazy). Bars to dogbones to dragbars. And the dished peanut tank I won from an awesome painter dude. More on that in a future post.

    The really bummer is the need for engine work. More on that in the next post below...

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    Engine deal. The seller kick-started the bike when I was picking it up. He's a big dude. But it was obvious that there wasn't a lot of grunt needed to kick it over. When I got it home, over the next couple days, I went to fire it up and noticed very low compression. WAY too easy to kick.

    It has electric start too. So I spun it a bit and got it to fire. Blue-ish white smoke puff from both pipes. Only on rev. No smoke at idle.

    Shut it down. Did a pushrod check (solid lifters). All 4 were really tight. Got them back in spec. Buttoned all back up. Fired again... this time with kick... and had a lot better compression. Felt more normal to kick over than the super light stroke before. So that felt like a win.

    But still puffing a bit but not nearly as bad. Took it for a spin. Rode well. Has a super 'E' on it that I fiddled with it a bit. No big deal.
    Was hoping that it had just been sitting for a while and that the rings needed to get comfy again or something.

    But once it got warmed up... about 5 minutes into the ride... started the knocking.
    Only happens when I'm loading the engine and it's fairly loud and obvious. Not a tick. Can't tell if front or rear or both.
    Mainly when I'm pulling out from a stop and getting on it in low RPMs or when I was going up hill with anything less than high RPMs.

    Got it home. Pushrod check again... everything is still in spec. No change.
    Checked all oil passageways (incl rocker box to rocker box) and confirmed all is good oil flow and return.
    No real leaks other than from the loose oil tank cap. No weird air or gas evidence in the oil tank or drain either.
    Still puffs a bit of blue-ish smoke. But even less than before. And I think mostly from the rear head but not exclusively.

    Waited a couple weeks. Got back on it this past weekend. Same story. Fired up brilliantly (2nd kick). Initial warm up great.
    Bit of smoke on startup but went away.
    First 5 minutes of ride were fine. Then the knock on loaded and low RPM revs.

    So... thoughts?
    At least a valve job all around?
    Possibly pistons too with a cylinder hone if not too bad of a shape?
    Wondering if this winter I should plan on just taking it apart jugs-up and getting the whole lot straightened out?
    Or... more financially forgiving... are there "steps at a time" to take? What would you do next?

    Everything else on the sad list in the post above is easy enough to go through.
    It's the engine challenges that worry me... just how far the rabbit hole goes.

    Would love you guys' input and advice.

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    First 5 minutes of ride were fine. Then the knock on loaded and low RPM revs.
    Got a bore scope? Cause, I think that's what mine did when the piston was galled and slapping.


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    No bore scope unfortunately. I may have to consider that. But the more I talk to other folks, the more likely it seems that I should just pull the heads and have the valves, guides, seals done to be sure, and while it's open, see what I can see.

    In other news, here's why I'm calling it the "Cosmic Shovel".
    A while back I actually won one of those Instagram raffles... for a gas tank.

    The good dude, and awesome painter, Travis (@travisstuckey) did up this dished tank with the old school Tom Fugle inlay technique in the dishes and on the gas cap. Pictures don't do it justice. The surface is smooth as glass, but when you start to stare at it, it just warps into another dimension. The best word I could come up with to describe it... was "cosmic".

    Eventually this tank will go on this bike, along with some of the other details I mentioned in the first post. Should be pretty fun.

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    To get bargaining leverage and know condition I bring my own compression tester and plug wrench when I go anywhere I might buy a bike, and I've even bought one from the auto store when a surprise Norton popped up.

    I'd just pull the top end because what is not inspected is not known, inspect the lifter screen for chips which is wisely done every oil change and takes just minutes, and pull the tappet blocks to inspect tappets, bores, cam lobes and timing chest.

    If all is well you're only out gaskets and seals but top ends on ancient aircooled engines with coarse finned iron cylinders are accepted as a periodic overhaul item. (My mentor said he missed the days when winter brought him heaps of British and HD top end jobs.) It's a 1930s engine design only slightly modernized but that's what makes 'em easy to work on.

    I don't do stuff based on wishful thinking after learning the hard way as a kid. A few hours inspection is worth doing and if it needs the work it best to find out early! Vintage motorcycles are not an especially expensive hobby but if bucks are tight ya can always park it and ride something else. (He who makes his project his daily is frequently a pedestrian so I don't.)

    When I get new to me cone bottom HD it gets a complete new charging system and the belt drive big twins get a fresh belt but if bucks are tight ya can inspect the stator (overheated windings look overheated), rotor (for magnet shift, all should be attached and at the same distance apart, they usually just shift but a loose magnet hitting a stator makes an impressive mess) and the connector between alternator/regulator for damage and burning (you can replace the connector but it's so easy to solder and heat shrink the wires then fill the hole with ThreeBond/Hondabond/Yamabond/Toyota FIPG (rightly a cult favorite) if it was mine I'd do that rather than buy another of those somewhat silly connectors. I clean them then dab some dielectric grease into the connector to exclude water and oil.

    Cracked (or was cracked) one of the oil tank tabs on frame (that's ok... 1 out three mounts aint bad right?)
    Now the rest take more load with predictable results so I'd build it back stronger (and depaint the others to inspect for cracks as the tank will be removed anyway).

    If I remove an oil bag I replace all the shock mounts as a set (anti-seize the threads so a stuck nut doesn't twist a shock mount apart) since they age badly. It's been years since I did mine so someone probably sells stronger urethane mounts and IIRC there is some industrial mount that swaps.

    I consider tired used bikes more of a mockup on wheels than a running proposition unless I know the last person to work on them and what they did and straight up warn prospective buyers to expect to go through them axle to axle. Then they'll be right afterwards. If you were expecting to hop on and go, now ya know. Most bikers learn the hard way but it looks to have decent bones. You can have it skinned out in a weekend.

    Since it's chopped it's easy to rewire and if everything is not top notch, be kind to yerself and do that too. At least wiring is cheap. I pull points plates and inspect advance mechanisms and if electronic ignition is fitted I inspect the pickup (some old HD pickups have their potting compound revert and drip like candle wax, often still working).

    just how far the rabbit hole goes.
    What could possibly happen? (runs)
    Last edited by farmall; 11-17-2022 at 6:10 PM.

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    Woah - loads of top notch advice. Thanks man! That should make it's way into a sticky somehow.

    As a bit of an update, I might have stumbled on a short term "aha moment" solution. When I got the bike home initially I ran thru the carb, checked the pushrods, spark plugs, fuel system, all that jazz. But somehow I failed to remember to check the ignition timing as a part of the basic tune up.

    In online searching for what this engine knock sound could be, I came across info and videos on detonation (aka pre-ignition). I recall reading a number of threads here in the chopcult with references to detonation but I personally had never experienced it on a bike. So I wasn't really positive what to listen for and how do you listen for something that you don't know what it sounds like? But the more I read and watched, the more it sounded like what was going on. And the #1 culprit for detonation is ignition timing that is way too advanced.

    Yesterday I cracked open the timing hole and nose cone and ran thru it. Sure enough, it was timed WAY advanced. Like... flywheel timing line rotated well beyond the hole type advanced. So I reset it back to dead center in hole and set the ignition plate. Just to have a straight up baseline that I can then adjust from there in the future. That all seems fine now. But it's a tad bit chilly here right now, and I've been swamped with classes and work. Wasn't able to get out for a test ride just yet.

    Fingers crossed that I can get out for some additional road testing to see if that resolved the low rpm loaded knocking sound.

    If it fixes the problem - cool. Then I'll still do the rest of the checks farmall suggested here over the winter. Since who knows what kind of stress the detonation was putting on the bike in the process.

    If it doesn't fix the problem - then I know I'm in for some additional deep dive.

    We'll see!

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    Good catch, I was there once and what I did was tear it apart, winters are long up here in Maine. I didn't know squat but by the spring I was well into my Harley addiction. That was around 1980 and the bike was a 77 FXE. There wasn't much wrong with her but I went into the engine anyway, they could always use rings, right! Plus a paint job. I just cleaned and polished and started reading Easyriders and devouring anything written that said Harley Davidson, learning with each page. Do it! But first thing, go out and buy the Harley service manual, not the Clymer or any other that claims to know. The dealers most likely won't let your machine in the door so find a mechanic or a shop that you can talk to and get your parts and stuff. I would have loved to have had the internet at my disposal, there is so much knowledge here, take it and use it, just beware that there are those that don't have a clue and profess otherwise. Take a lot of pics if your not sure of what your in to. Your not going to go where no one has gone before. Good Luck

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    One of my bros was helping another replace Twin Cam timing chain guide shoes.
    All seemed well until a few days later when the bike wouldn't start. They were chasing various possible problems but they forgot to "inspect the most recently disturbed part", even swapping a cam position sensor.

    One finally pulled the pushrod tubes. One cylinder was fine but both the others pushrods had completely backed off because someone had bottomed both pushrod lock nuts in the wrong direction! Those lock nuts ain't decorative. No damage was noted and after proper adjustment and using lock nuts as intended the bike ran fine.

    Shit happens and adults share their fuckups to help others learn from someone else's mistakes.

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