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  • 78XS rehab

    Hi all, new member and new owner of a hopefully-salvagable 78XS. I was on the hunt for a 70s era moto when this dropped into my lap for nothing. It had been ran approx 2 years ago, then left outside under a tarp... mostly under a tarp. It's got around 10K miles, and I was looking for something to fix anyway, so I'm trying my luck!

    My goal right now is to see if the engine is salvageable while spending the least amount of cash to find out. If it's fixable for a reasonable price (parts wise, I'm the labor) I'll get to work and buy what's needed.

    So here's where I'm at! Surface rust in places but haven't found rot. Tank's in OK shape, a patina inside but doesn't look terminal. Put a bit of seafoam in the tank and it made it to the carbs after a few minutes - and the carbs had around a tablespoon of gas in each when I picked it up. Air filter made for pleasant mouse bungalo, but the mesh held up and filo didnt make it further in.

    With another battery all the lights, horn work. I changed the oil (dark brown) and put some on top of each of the cylinders. Plus looked carbony, one in particular but not caked in it (that one, a bit).
    Screwed the plugs in and left them unplugged, and tried the starter to circulate the oil and see if it would turn over.

    Nothing. Fuses look fine (not exactly in a fuse box however), i check the switch. A little corroded, I rebuild it. Now, when I press it I see the headlight dim slightly, but nothing happens. Switch is working, next up solenoid.

    Solenoid is very, very rusted inside. The spring was rust-locked to the cylinder. Broke it down (solder and all - hadn't done that since shop class), cleaned and ground off a little rust with sand paper. Reassembled, remounted, success! Now, it clicks when I press the starter, and thats it.

    And thats it. It rolls, with a little resistance, in neutral and on 1 when clutch is pulled. The resistance is I suspect because of the rear brake (it seemed to roll easier before i tried the rear brake). I tried a wire across the two solenoid terminals and the bike twitches - I can hear the starter straining against something immobile in there. Got my Haynes manual coming in a few days, but I'm not sure they cover this kind of neglect, and I'd rather not part it out!
    Any suggestions as to what to try next?

  • #2
    Welcome!! where are you from?
    82 XJ1100J
    81 Venturer
    Newly acquired Aches N Pains collection

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    • #3
      Thanks! I'm an east coaster myself - Rhode Island

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      • #4
        Welcome EAB, You have lots to work with. Electrical is often an issue. Cleaning grounding points and changing the fuse panel for a more modern one is standard operating procedure around here. Original workshop manual available for down load. http://www.ringler.us/family/mybike.html
        I printed mine and put in a binder.
        Phil
        1981 XS1100 H Venturer ( Addie)
        1983 XJ 650 Maxim
        2004 Kawasaki Concours. ( Black Bear)

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        • #5
          Thanks for the tip, I'll check it out. I'm worried though that the motor might be seized due to its time in the elements. Can you think of any quick and dirty way to check for that - that wouldn't do more harm than good, if it is indeed salvageable? I'd heard reference to manually rotating the crank shaft to loosen things up after sitting. But the only way I can think to try (rolling it a few feet then popping the clutch) doesn't work, it just stops dead.

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          • #6
            See if it still has the emergency kick start lever located under the tool box. It's tucked away nice & neat. You really have to look for it.
            79 F full cruiser, stainless brake lines, spade fuses, Accel coils, modded air box w/larger velocity stacks, 750 FD.
            79 SF parts bike.
            guns, beer and bikes
            what more could you ask for.

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            • #7
              Unfortunately it didn't come with this one :[ I see the mounting point, but no pedal. Maybe my cheapest option would be to buy one and try that? I suppose I could resell it afterwards if the engine is locked up for the duration, found one on ebay for $35 or so. Hrm.

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              • #8
                Hey there Eab, Bax here just a bit further North in NH. Seems you gots the link to the shop manual. Just turning the engine is easy. Remove the left timing cover and using a 3/4" wrench you can rotate the crank manually. Should be enough to tell you if it's locked up.

                Bax
                80 SG

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                • #9
                  She spins! Not a whole lot, but it's not locked up!

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                  • #10
                    Originally posted by Eab View Post
                    She spins! Not a whole lot, but it's not locked up!
                    Hi Eab, That is encouraging. I hope you checked the arrow on the timing plate and turned the motor in the correct direction. These motors do not like being rotated backwards. I would suggest pulling the plugs and adding a small amount of ATF ( transmission fluid) and let it soak for a day or two.
                    Phil

                    1981 XS1100 H Venturer ( Addie)
                    1983 XJ 650 Maxim
                    2004 Kawasaki Concours. ( Black Bear)

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                    • #11
                      ditto on the auto trans fluid in the spark plug hole,,,,,pour some, around a couple tbspoons,,,crank in a couple days,,,,clean replace plugs,,,expect some smoke from the first time you fire up the engine from the tranny oil, but it usually burns off in a hurry. Expect a lot of smoke, and maybe rust particles on start up from the ol pipes,,,,probably need the usual go through,,,,plugs, carb clean grounds, battery connectors, install fuel filter if none, change trans fluid and rear differential fluid, good battery or jump from car for first start,,,,pray, and hope it fires up......Mike in Sunny Diego

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                      • #12
                        If you mix ATF and Acetone, 50/50, it gets deeper into the problem area. That is the #1 formula for freeing up rusted bolts on the Left coast.
                        The starter is easy to remove, and with a little clean-up will probably work for years to come.
                        On ALL ground wires for the bike, remove bolts, clean everything of rust, coat with anti-seize, and replace. I also put a second ground from the battery to an engine bolt, just because I've worked on too many "critical" things in the past.
                        Ray Matteis
                        KE6NHG
                        XS1100 E '78 (winter project)
                        XS1100 SF Bob Jones worked on it!

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                        • #13
                          Thanks for the tips, all! Got the chems en route and will be trying them tomorrow. Also got a new, proper moto battery. If there's anything else aside from a siezed engine that'd make a rebuild not so feasible I'd love to hear about it

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                          • #14
                            Since your located in a high humidity area, I highly reccomend you also remove and take apart the the Run/Stop switch and soak the whole switch in a cup of Evapo-Rust for afew hours. remove and wash off switch assembly with water, blow dry and re-install. The run/stop switch COMPLETES the running circuit, and if contacts are cruddy the electrickery will not get to coils in order to fire the cylinders. The wires plug-in for that switch is under fuel tank on top right frame rail.
                            Last edited by motoman; 09-27-2020, 02:55 PM.
                            81H Venturer1100 "The Bentley" (on steroids) 97 Yamaha YZ250(age reducer) 92 Honda ST1100 "Twisty"(touring rocket) Age is relative to the number of seconds counted 'airing' out an 85ft. table-top.

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                            • #15
                              Once you get that shop manual, just plan on servicing the entire motorcycle from nose to tail. Start front, work to back. Everything needs adjusted, lubed, replaced per the FSM. Just doing that could get you a running machine. If not, you won't have far to go.
                              Marty (in Mississippi)
                              XS1100SG
                              XS650SK

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